Practical skills

Raw and synthetic materials

Plants

Adaptations

Light & dark

Magnetism

States of matter

Rock cycle

Human anatomy

Ecosystems

Electrical circuits

Sound

Separating mixtures

Physical and chemical changes

Reproductive cycles

Notable scientists

Forces

Space

Particles in physical and chemical changes

Sustainability

Humans and animals over time

Diet and lifestyle

Light

History of science

Science

Y5 Science

Key Stage 2

Year 5

UNIT

In this lesson, we find out what happens to the arrangement and behaviour of particles during a change of state. Learn about the properties of solids, liquids and gases and how to identify changes of state.

What happens during a state change?

﻿Hello there, my name is Miss Couves. What's your name? I'm so excited to see you today. We are going to begin a brand new unit on chemical and physical changes. Today, we're going to learn about how particles behave in solids, liquids, and gases, and what happens when we heat substances up and cool them down. Are you ready? Today we will restart by recapping our previous knowledge. Then we will look at the properties of solids, liquids, and gases. We'll find out what happens to substances when they are heated or cooled, and what these changes of state are called. For this lesson, you will need a piece of paper or an exercise book and a pencil. If you don't have one of these items, pause the video now and go and get it. Let's start by recapping our previous knowledge. Can you remember which state of matter each diagram represents? The first diagram shows the particles touching in ordered rows. Which state of matter does the diagram represent? This diagram represents a solid. In solids, the particles are touching and arranged in ordered rows. The second diagram has particles that are touching but arranged randomly. Which state of matter does this diagram represent? This diagram represents a liquid. The particles in a liquid are touching but not arranged in ordered rows. The final diagram shows particles that are not touching and moving very fast. Which state of matter does this diagram represent? This diagram represents a gas. The particles in a gas do not touch and move quickly in all directions. We use separating techniques to separate mixtures into pure substances. When do we use filtration? We use filtration to separate an insoluble solid from a liquid. When do we use sieving? We use sieving to separate an insoluble solid from a liquid when the solid is large enough not to fit through the holes in the sieve. When do we use evaporation? We use evaporation to separate a soluble solid from a liquid because the liquid has a much lower boiling point than the soluble solid. Let's think about the properties of solids, liquids, and gases. We are going to start by thinking about the arrangements of particles in solids, liquids, and gases, and how the particles behave. Pause the video and copy this table into your notes. When you're ready to continue, press play. The particles in a solid are close together. They are touching. The particles are arranged in ordered rows, and the particles are vibrating on the spot. Pause the video to complete the first row of your table. Press play when you're ready to continue. Particles in a liquid are also close together. They are also touching. The particles are arranged randomly, and the particles are able to slide past each other. Pause the video to complete row two of your table. Press play when you're ready to continue. The particles in a gas are far apart. They are arranged randomly and moving in all directions. The particles move fast in all directions. Pause the video to complete the final row of your table. Press play when you're ready to check your answers. Pause the video to tick and fix your answers. Pause the video and write a sentence to describe the particles in a liquid. Pres play when you're ready to continue. The particles in a liquid are touching and arranged randomly. They are moving and able to slide past each other. Now we're going to look at the properties of solids, liquids, and gases. Solids cannot be compressed because there is no space between the particles. They do not flow because the particles cannot move past each other. And they have a fixed shape because the particles cannot move past each other. Three properties of solids are that they cannot be compressed, they do not flow, and they have a fixed shape. Pause the video and write down three properties of solids. Press play when you're ready to continue. Three properties of solids are that they cannot be compressed, they cannot flow, and they cannot change their shape. Let's look at the properties of liquids. Liquids cannot be compressed because there is no space between the particles. Liquids can flow because the particles can slide past each other. And liquids can take the shape of the bottom of the container because the particles can slide past each other. The three properties in liquids are that they cannot be compressed, they can flow, and they can take the shape of the bottom of their container. Pause the video and write down three properties of liquids. Press play when you're ready to continue. Let's look at the properties of gases. Gases can be compressed because there is space between the particles. They can flow because the particles are moving all of the time in all directions. And they can fill the shape of their container because the particles are moving all of the time in all directions. Three properties of gases are that they can be compressed, they can flow, and they can fill the shape of their container. Pause the video and write down three properties of gases. Press play when you're ready to continue. Now we're going to look at what happens when we heat or cool particles. Particles in a solid are vibrating on the spot. In a liquid, they're sliding past each other. And in a gas, they're moving fast in all directions. As a substance is heated, the temperature increases. When the temperature increases, the particles have more energy and will move around more. What happens to the particles when they are heated? When particles are heated, they have more energy. Pause the video and write down what happens when particles are heated. Press play when you're ready to continue. When particles are heated, their particles gain energy and move around more. Pause the video and complete this diagram in your notes. Press play when you're ready to continue. Pause the video to tick or fix your answer. Check that your diagrams match the diagrams on this slide and that you identified that as the temperature increases, particles have more energy. When substances are cooled, the particles have less energy. This means that they move around less. Now we're going to think about changes of state. A change of state happens when something change from one state of matter to another. When a solid becomes a liquid, it is called melting. My turn, melting. Your turn. Which change of state is called melting? Melting is when a solid changes to a liquid. When a liquid becomes a gas, it is called boiling. My turn, boiling. Your turn. What is boiling? Boiling is when a liquid becomes a gas. When a gas becomes a liquid, it's called condensing. My turn, condensing. Your turn. Which state change is involved in condensing? Condensing is when a gas becomes a liquid. When a liquid becomes a solid, it is called freezing. My turn, freezing. Your turn. Which change of state is called freezing? Freezing is the change of state from a liquid to a solid. Pause the video and complete the diagram in your notes. Press play when you're ready to check your answers. Pause the video to tick and fix your answers. Press play when you're ready to check your knowledge. Which state changes involve particles gaining energy? Option one, melting. Option two, boiling. Option three, condensation. Option four, freezing. What do you think? State changes that involve particles gaining energy are melting and boiling. Which state changes involve particles losing energy? Option one, melting. Option two, boiling. Option three, condensation. Or option four, freezing. What do you think? The state changes that involve particles losing energy are condensing and freezing. Pause the video and complete the table to identify the state change and how you knew. For example, for the first question, when steam is produced from a kettle, a liquid is turning into a gas. Which state change is that? This is evaporation or boiling. How did I know that? I know that it was boiling because a liquid turned into a gas. Pause the video to complete the table. Press play when you're ready to check your answers. Pause the video to tick or fix your answers. Steam produced from a kettle is boiling because liquid water is becoming a gas. Rain turning into snow is freezing because liquid water is becoming a solid. An ice cream on a hot day melts because the solid ice cream is becoming a liquid. And water forming on the bathroom mirror is condensing because steam is becoming a liquid. Well done for all your hard work today. You've learned so much about the changes of state. Make sure that you do your quiz so that you can recap your knowledge. See you next time, bye!

In this lesson, we find out what happens during a physical change, look at examples of physical changes and complete our own investigation into the physical change that occurs when chocolate melts.

What is a physical change and how can we identify them?

﻿Hello again. How are you today? Are you excited for our lesson? I am really excited as today we're going to be learning about physical changes. And we will be having a go at an investigation into a physical change ourselves. Ready? Let's get started. In today's lesson, we will start by recapping our previous knowledge. Then we will look at what a physical change is and some examples. Finally, we'll be investigating a physical change. In today's lesson, you will need an exercise book or paper and a pencil. If you don't have one of these items now, pause the video and go and get them. Press play when you're ready to continue. If you would like to have a go at our experiment, you will need a bar of chocolate and a lamp like the one I have here. You will also need an adult to help you. Let's get started by recapping our previous knowledge. Can you remember the properties of solids, liquids and gases? Pause the video now and complete the table. Press play when you're ready to check your answers. Pause the video to tick and fix your answers. Pause the video and complete the diagram in your notes. What do the particles look like in solids, liquids and gases? Press play when you're ready to check your answer. Particles in solids are touching and in ordered rows. In liquids, they are touching and arranged randomly. And in gases, they're far apart, not touching and moving very fast. As you increase the temperature, particles have more energy. What state change happens when a solid becomes a liquid? When a solid becomes a liquid, it is called melting. What is it called when a liquid becomes a gas? When a liquid becomes a gas, it is called boiling. What is it called when a gas becomes a liquid? It is called condensing. What is it called when a liquid becomes a solid? It is called freezing. Today we're going to think about physical changes. A physical change is a change in the form or arrangement of a substance. For example, an ice cream melting, paper tearing, or glass smashing. What happens when I tear this piece of paper? It is still paper. Yes, it is still paper. So the particles are still paper particles, however, the arrangement or form has changed. I now have two smaller pieces of paper rather than one big piece. The form or arrangement of the substance has changed, but the substance itself has stayed the same. In all of these examples, ice cream melting, paper tearing, and glass smashing, the form or arrangement of the substance has changed, but the type of particle has stayed the same. Pause the video and write down three examples of physical changes. Press play when you're ready to continue. What is a physical change? A physical change is a change in the form or arrangement of a substance. Three examples of physical changes are ice cream melting, paper tearing and glass smashing. What is the same before and after the physical change? The type of substance or particle is the same before and after the physical change. Let's think about some examples. Remember, when we are identifying a physical change, it is when the form or arrangement has changed, but the type of substance has stayed the same. Is this a physical change? Water boiling in a saucepan. What particles are present at the start? What particles are present in the end. Has the arrangement of the particles changed? Is this a physical change? What do you think? This is a physical change because the water particles are changing arrangement from a liquid to a gas, but the substance or type of particles remains the same. It is still water just in a different form. Is this a physical change? Ice melting in my drink. What particles are present at the start? What particles are present at the end? Has the arrangement of the particles changed? Is this a physical reaction? What do you think? This is a physical reaction. This is a physical change because the water particles are changing arrangement from a solid to a liquid, but the substance or type of particle remains the same. It is still water just in a different form. Is this a physical change? A bonfire burning. What particles are present at the start? What particles are present at the end? Has the arrangement of the particles changed? Is this a physical change? What do you think? This is not a physical change because when the wood burns, it produces ash. This is a different type of substance, rather than a different form of the same substance. So it's not a physical change. Is this a physical change? Soap dissolving in water. What particles are present at the start? What particles are present at the end? Has the arrangement of particles changed? Is this a physical reaction? Sorry, is this a physical change? What do you think? This is a physical change because the salt and water particles are changing arrangement from a solid and a liquid to a solution, but the substance or types of particle remain the same. It is still water and salt. They are just in a different form. We are going to investigate what happens when chocolate melts. Let's start by thinking about the particles in chocolate. Pause the video and complete the diagram. What do the particles of chocolate look like when they're a solid and when they're a liquid? The particles of a solid are arranged in ordered rows, whereas the particles in the liquid are arranged randomly. What will happen to the energy of the particles when they melt? The particles will have more energy. To do our experiment, we're going to place one square of chocolate on a plate. We're going to place the lamp directly facing the chocolate and turn the lamp on. We're going to watch what happens to the chocolate for three minutes before turning the lamp off. If you'd like to have a go at this experiment, you need to get yourself a lamp, some chocolate and an adult to help you. Press pause and go and find someone to help you. If you prefer to watch me do the experiment, you can watch me do it now. I am going to place a few squares of chocolate into my glass . And I'm going to place the lamp at the top of the chocolate so that I can heat it up. I've turned my lamp on. The lamp is going to get hot. Make sure that you don't touch the lamp. Watch carefully to see what happens to the chocolate. We're going to heat the chocolate for three minutes to see what happens. You may need to leave your experiment a little bit longer than three minutes before you start seeing the chocolate melt. Make sure that you don't touch the lamp, which will get very hot during this time. Have a look at my chocolate. Can you see that the solid is turning into a liquid? It is starting to lose its shape. What has happened to the particles during melting? The particles have gained energy and they're now able to move past each other. How do I know that this is a physical change? I know that this is a physical change because the particles are still chocolate particles, they're just arranged in a different way. What has happened to the chocolate when we placed it under the lamp? What happened to the energy of the particles during this process? Draw a particle diagram to represent the particles at the end of the investigation. Is this a physical change? How do you know? Pause the video and complete the questions in full sentences. Press play when you're ready to see the answers. Pause the video to tick or fix your answers. Question one, the chocolate melted when it was placed under the lamp. During the melting process, the chocolate particles gained energy. The particles in a liquid are touching and not arranged in ordered rows. They are arranged randomly. This is a physical change because when the chocolate is melting, the arrangement of particles changes, but the actual type of particle does not. Thank you for all your hard work in our lesson today. I can see that you have been working really hard. Have a go at the quiz to recap your knowledge. See you next time. Bye.

In this lesson, we will find out what happens during a chemical change, look at some examples of chemical changes and practise representing chemical changes using word equations.

What is a chemical reaction and how can we identify them?

﻿Hello again, my name is Miss Couves. I am really excited about our lesson today. In today's lesson, we are going to be looking at chemical changes. Chemical changes are really important to scientists. We use them for all sorts of things; from keeping us warm, to designing new medications. Scientists that study chemical reactions are called chemists. Today, we are going to be chemists and study some chemical reactions. In today's lesson, we will begin by recapping our previous knowledge. We will then find out what a chemical reaction is, look at some examples and then find out how scientists represent chemical changes using a word equation. For this lesson, you will need: an exercise book or paper and a pencil. If you don't have one of these items, pause the video now and go and get them. Press play when you're ready to start. Let's start by recapping our knowledge. Can you remember the properties of solids, liquids and gases? Pause the video now and complete the table. Press play when you're ready to see the answers. Pause the video to tick and fix your answers. Solids cannot be compressed, do not flow and cannot change their shape. Liquids cannot be compressed, but they can flow and they take the shape of the bottom of their container. Gases can be compressed and they can flow and they fill the shape of their container. Pause the video to complete the diagram in your notes. Press play when you're ready to continue. Particles in solids are touching and in ordered rows. In liquids, they are touching and arranged randomly. And then in gas, they are far apart, not touching and moving very fast. What happens as you increase the temperature? As you increase the temperature, particles have more energy. Which state change involves a solid becoming a liquid? Melting involves a solid becoming a liquid. Which state changed involves a liquid becoming a solid? Freezing involves a liquid becoming a solid. Which state change involves a liquid becoming a gas? Boiling involves a liquid becoming a gas. Which state change involves a gas becoming a liquid? The state change that involves a gas becoming a liquid is called condensing. What is a physical change? A physical change is a change in the form or arrangement of a substance. We have three examples: ice cream melting, paper tearing and glass smashing. Why is glass smashing an example of a physical change? Glass smashing is an example of a physical change because the form of the glass changes from a large pail to lots of tiny shots, but the type of substance doesn't change, it is still floss. Now we are going to learn about chemical changes. Chemical changes are sometimes called reactions. My turn reactions, your turn... A chemical reaction is a change that forms a new substance. My turn a chemical reaction is a reaction... A chemical reaction is a change that forms a new substance. Your turn. Right. I'm going to show you an example of a chemical reaction. For this, I'm going to need my lab coat. This is an experiment that you shouldn't try at home. The experiment that I'm going to do is burning paper. Here I have a piece of paper. I'm going to light my paper using a match. When I light the paper, I want you to look really carefully at what happened while the paper burns. Can you see the paper burning? What's happening to the paper while it burns? Can you see the block solid that's being produced? That's called ash. The paper has turned black and some small white fragments have been produced. They're called ash. The paper is no longer the same substance. When I burn the paper, it turned into two gases, water and carbon dioxide and ash. Because burning produces new substances, it's a chemical change. Let's look at some other examples. Other examples of chemical changes are: a match burning, a cake baking and a bike rusting. Why is it bike rusting an example of a chemical change? A bike rusting is an example of a chemical change because a new substance is formed. Pause the video and write down three examples of chemical reactions. Press play once you're ready to continue. What is a chemical reaction? A chemical reaction is a change that forms a new substance. For example, a match burning, a cake baking and a bike rusting. Let's look at some examples. For these examples, you need to decide whether it is an example of a chemical change. What is a chemical change? A chemical change is a change that forms a new substance. So in all of these examples, we're looking for whether a new substance is formed. Is this a chemical reaction? Toasting bread. What particles are present at the start? What particles are present at the end? Has a new substance been formed? Toasting bread is an example of a chemical reaction because a new substance is formed. What about this? Is this a chemical reaction? A bonfire burning. What particles are present at the start? What particles are present at the end? Has a new substance been formed? What do you think? Is this an example of a chemical reaction? A bonfire burning is an example of a chemical reaction because a new substance has been formed. Is this a chemical reaction? Mixing sand iron filings. What particles are present at the start? What particles are present at the end? Has a new substance been formed? What do you think? Mixing sand and iron filings is not an example of a chemical change because a new substance has not been formed. The mixture can be easily separated to get the iron and sand back. Can you remember how to separate sand and iron filings? You can separate sand and iron filings using a magnet because iron is magnetic and sand is not. Is this a chemical reaction? Burning metals like lithium in fireworks. What particles are present at the start? What particles are present at the end? Has a new substance been formed? What do you think? Burning metals in fireworks is an example of a chemical change because a new substance is formed. What is a chemical reaction? A chemical reaction is a change that forms a new substance. Scientists use word equations to represent changes that occur in chemical reactions. Reactants are the substances at the beginning. Products are the substances at the end. When we read a word equation, when we get to arrow, we say the word produces because we are saying that a chemical change has taken place. So I would read my word equation as reactants produce products. What goes on the left-hand side of the arrow? The reactants go on the left-hand side of the arrow. What are the reactants? The reactants are the substances present at the beginning of a reaction. What goes on the right-hand side of the arrow? The products go on the right-hand side of the arrow. What are the products? Products are the substances formed in a reaction. Let's think of an example. In this chemical change, cookie mixture is producing a cookie. What is the reactant? In this example, the reactant is the cookie mix. Where does the reactant go in a word equation? The reactant goes on the left-hand side of the arrow. What is the product in this chemical reaction? The product and its chemical reaction is the cookie, 'cause it is formed in the reaction. Where does the product go in the word equation? The product goes on the right-hand side of the arrow. What are these word equations describing? I'm going to read them to you, then you can pause the video to describe the word equations using a sentence. Number one, cake mixture produces cooked cake. Two, bread produces toast. Three, explosive powder produces firework ash. Four, iron plus oxygen produces iron oxide, which is also called rust. Use this sentence starter to help you describe the word equations. The word equation describes the chemical reaction that takes place when? Pause the video to describe all four word equations. Press play when you're ready to continue. For number one, the word equation describes the chemical reaction that takes place when a cake mixture is cooked to produce cooked cake. Number two, the word equation describes the chemical reaction that takes place when bread produces toast. Number three, the word equation describes the chemical reaction that takes place when explosive powder produces firework ash. Number four, the word equation describes the chemical reaction that takes place when iron and oxygen produce iron oxide. Write the word equation for the following. I'm going to read all four examples to you. Then you can pause the video to write the word equations. Number one, cookie dough reacts to produce cooked cookies. Number two, a bike reacts an air to form rust. Three, a match reacts with oxygen to produce carbon dioxide and water. Number four, carbon and oxygen react to produce carbon dioxide. Remember the reactants go on the left-hand side of the arrow and then products go on the right-hand side of the arrow. Pause the video and write four word equations. Press play when you're ready to continue. Number one, cookie dough produces cooked cookies. Number two, bike plus air produces rust. Number three, match plus oxygen produces carbon dioxide and water. Number four, carbon plus oxygen produces carbon dioxide. Well done for all your hard work today, you have been an excellent chemist. We've looked at chemical reactions and how scientists represent them using word equations. And you've written your own word equations. Remember to do the quiz to show everything that you've learned in today's lesson. See you next time.

In this lesson, we will compare the characteristics of chemical and physical changes and use our knowledge to categorise changes as either physical changes or chemical reactions.

What is the difference between physical and chemical changes?

﻿Hello, again. My name is Miss Couves, and I am so excited to teach you science today. In this lesson, we're going to learn about chemical and physical changes, and how to identify whether a chemical change or a physical change has happened. Let's get started. In today's lesson, we will start by recapping our previous knowledge. Then we will look at some examples of physical changes and chemical reactions. Then we will compare the characteristics of chemical and physical changes. And finally, we will identify what sort of change has happened. In this lesson, you will need an exercise book or paper, and a pencil. If you don't have one of these items, pause the video now and go and get them. Let's start by recapping off previous knowledge. Can you remember the properties of solids, liquids and gases? Pause the video to copy and complete the table. Press play when you're ready for the answers. Pause the video to tick and fix your answers. Remember that solids cannot be compressed, they cannot flow, and they cannot change their shape. Liquids cannot be compressed, but they can flow and they take the shape of the bottom of their container. Gases can be compressed, and they can flow, and they fill their container. Why can gases be compressed, but liquids and solids can't? Gases can be compressed because there is space between the particles. There is no space between the liquids and solid particles, so they can't be compressed. Pause the video to complete the diagram in your notes. Press play when you're ready to continue. Particles in solids are touching and in ordered rows. In liquid, they are touching and arranged randomly. And in gases, they are far apart, not touching and moving very fast. As you increase the temperature, particles have more energy. Pause the video and label all of the state changes. Press play when you're ready to hear the answers. The state change from a solid to a liquid is called melting. The state change from a liquid to a gas is called boiling. The state change from a gas to a liquid is called condensing. The state change from a liquid to a solid is called freezing. What is a physical reaction? A physical change is a change in the form or arrangement of a substance. Why is glass smashing an example of a physical change? Glass smashing is a physical change because the form of the glass changes from a large pane to lots of tiny shards. But the type of substance doesn't change, it is still glass. Why is paper tearing a physical change? Paper tearing is a physical change because the form of the paper changes from a large sheet of paper to lots of tiny pieces. But the type of substance doesn't change, it's still paper. Why is an ice cream melting an example of a physical change? Ice cream melting is an example of a physical change because the form or arrangement changes. As the particles change from a solid to a liquid, they become less ordered. So the arrangements of particles are changing, but the types of particles stays the same. It's still ice cream particles. What is a chemical reaction? A chemical reaction is a change that forms a new substance. Let's think about wood burning. When wood burns, it produces carbon dioxide and water. Two new substances have been produced. So this is an example of a chemical reaction. When a bike rusts, the metal in the bike reacts with the oxygen in the air to form rust. A new substance rust has been formed, so this is a chemical reaction. What is formed in a chemical reaction? In a chemical reaction, a new substance is always formed. Scientists represent chemical reactions using word equations. A word equation has reactions before the arrow, and product after the arrow. What are the reactants? The reactants are the substances at the beginning of the reaction. Point to the reaction in the word equation. The cookie mix is the reaction because it is the substance present at the start. What are the products in a reaction? The products are the substances formed in a reaction. Point to the products in the word equation. The cookie is the product because it is the substance formed in the reaction. Let's look at chemical and physical changes in a bit more detail. What is a physical change? A physical change is a change in the form or arrangement of a substance. When ice cream melts, the particles loose their ordered arrangement, but the particles are still ice cream particles. The arrangement has changed but not the type of substance. Pause the video and write down why paper tearing or glass smashing is a physical change. Press play when you're ready to hear the answer. Paper tearing is a physical change because the form of this substance has changed. Rather than being a large sheet of paper, it is now smaller pieces. But the type of substance, paper remains the same. Glass smashing is a physical change because the form of the material has changed. Instead of being a large pane of glass, it is now lots of tiny shards. However the type of substance, glass remains the same. What is a physical change? Give one different example. Pause the video and write down one example of a physical change. Press play when you're ready to continue. You might have said, ice melting, or water boiling, or salt dissolving. All of these are physical changes because the arrangement of the substance has changed, but not the type of substance. What is a chemical change? A chemical change is a change that forms a new substance. What new substances are formed when a match burns? Burning is a combustion reaction. When wood burns, it produces carbon dioxide and water. This is an example of new substances being formed. So wood burning is a chemical reaction. How does scientists represent chemical reactions? They use word equations. Pause the video and have a go at writing the three word equations. Press play when you're ready to continue. Let's write the word equations together. For the match burning, what was the reactant in this equation? The reactant was the match, and it was reacting with the air. So air is also a reactant. I'm going to use an arrow to represent that my reactants are producing my products. What are the products when a match burns? When a match burns, the products are carbon dioxide and water. Let's have a go at number 2. Number 2 is the cake baking. What goes on the left-hand side of the arrow? On the left-hand side of the arrow, we put the reactants. What are the reactants in this reaction? The reactants are the cake mixture. What is produced in this reaction? A cake is produced in this reaction. Can you see how I'm making sure that I write all of the reactants on the left-hand side and all of the products on the right-hand side, even if that means I have to write them one underneath the other. Let's do the third example. The third example is a bike rusting. What are the reactants of this reaction? The metal bike reacts with oxygen from the air. What is produced in this reaction? This reaction produces rust. Pause the video and give an example of a chemical reaction. Press play when you're ready to continue. Did your reaction involves the formation of a new substance? What was the new substance? Can you write a word equation to represent your chemical reaction? Let's compare chemical reactions and physical changes. A physical change is when the form of a substance or the arrangement of particles changes. E.g. a change of state or dissolving. These changes are easy to reverse. So if I melt ice, that's an example of a physical change. It's really easy for me to change my water back to ice by freezing it. This is an example of a change that is easy to reverse. In physical changes we often see a change in appearance. A chemical reaction, it's when a new substance is formed. For example, burning or rusting. They are hard to reverse. Let's imagine my cake. When I bake my cake in the oven, it is really difficult for me to get my cake mixture back. This is an example of a change that is hard to reverse. In chemical reactions, we also often see a change in appearance. Pause the video to make notes on physical changes and chemical reactions. Press play when you're ready to test your knowledge. Pause the video, and copy and complete the Venn diagram. Press play when you're ready to check your answers. A new substance is produced only in a chemical reaction. The same substance changes form only in a physical change. There is a change in appearance, in both chemical changes and physical changes. Chemical changes are difficult to reverse and physical changes are easy to reverse. Pause the video to tick and fix your answers. Press play when you're ready to continue. Let's use our knowledge of chemical and physical changes to identify some changes. Before we start, let's check our knowledge. What is a physical change? A physical change is the change in the form of a substance. Is it easy or hard to reverse? A physical change is easy to reverse. Can you give me an example of a physical change? A physical change might be a change of state, or dissolving or tearing of paper. A chemical reaction is when a new substance is formed. Is a chemical change easy or hard to reverse? A chemical change is hard to reverse. Can you give me an example of a chemical change? A chemical change might be burning, or rusting, or making a cake. Pause the video to copy and complete the sentences, to identify whether these changes are chemical or physical. Press play when you're ready to hear the answers. Number 1, making toast is a because, number 2, snow melting is a because, number 3, a firework exploding is a because, a car rusting is a because, a puddle evaporating is a because, a fire burning is a because. If you're struggling to explain why something is a chemical or physical change, have a think back to the definition. What makes something a chemical or physical change? Making toast is a chemical reaction because a new substance is formed. Snow melting is a physical change because the substance changes form, but the type of substance change stays the same. A firework exploding is a chemical reaction because a new substance is formed. A car rusting is a chemical reaction because a new substance is formed. A puddle evaporating is a physical change because the arrangement of particles changes, but the type of substance remains the same. A fire burning is a chemical reaction because a new substance is formed. You've worked so hard learning about chemical and physical reactions today. I'm so impressed with all of the work that you have done. Make sure you've tried the quiz, so that you can show how much you've learned. See you next time.

In this lesson, we will learn about reactivity and how scientists investigate how reactive a substance is. We will conduct our own investigation into the reactivity of vinegar while looking at the variables we need to change, control and measure in our investigation.

What can we do to investigate chemical reactions?

﻿Hello, my name is Miss Couves. I'm really excited for our lesson today. In today's lesson, we're going to be investigating some chemical reactions. I am so excited for the experiment that we're going to do together later. Scientists investigate chemical reactions so they can find out more about how they work. Today, we are going to be investigating the chemical reaction between vinegar and sodium bicarbonate. Let's get started. In today's lesson, we are going to start by recapping our previous knowledge. Then we will learn about the reactivity and how we measure it. We will look at the variables in scientific experiments, and then we will finally plan our own experiment into reactivity. For today's lesson, you will need an exercise book or paper, and a pencil. If you don't have one of these items, pause the video now and go and get them. If you would like to have a go at the experiment, you will also need some vinegar, some bicarbonate of soda, a cup, and a spoon. You will also need an adult to help you. Let's start by recapping our knowledge. Pause the video to complete the diagram in your notes. Press play when you're ready to hear the answers. Particles in solids are touching and in ordered rows. In liquids, they are touching and arranged randomly. And in gases, they are far apart, not touching, and moving very fast. As we increase the temperature, particles have more energy. Pause the video to write down the four state changes that we have learned about. Press play when you're ready to hear the answers. The change from a solid to a liquid is called melting. The change from a liquid to gas is called boiling. The change from a gas to a liquid is called condensing. The change from a liquid to a solid is called freezing. What is a physical reaction? A physical reaction is a change in the form or arrangement of a substance. Why is glass smashing an example of a physical change? Glass smashing is an example of a physical change because the form of the glass changes from a large pane to lots of tiny shards. But the type of substance doesn't change. It is still glass. Pause the video and write down why paper tearing is an example of a physical change. What is a chemical change? A chemical change is a change that forms a new substance. Let's think about the cake baking. When the cake bakes, it produces a new substance. The cake batter looks very different to the cooked cake, and they have different properties. Because a new substance is formed, a chemical reaction has taken place. What a bike rusts, the metal in the bike reacts with the oxygen in the air to form rust. A new substance, rust, has been formed, so this is a chemical reaction. What is formed in a chemical reaction? A chemical reaction forms a new substance. Pause the video and write down why a match burning is an example of a chemical change. A physical change is when the form of a substance or the arrangement of its particles changes. For example, changes of state or dissolving. They're easy to reverse and often result in a change in appearance. A chemical reaction is when a new substance is formed. For example, burning and rusting. These changes are hard to reverse. They often result in a change in appearance. What is the same about chemical and physical changes? Both chemical and physical changes result in a change of appearance. What is different between physical changes and chemical changes? A physical change is easy to reverse whereas a chemical change is hard to reverse. A physical change changes the form of a substance whereas a chemical change produces a new substance. In today's lesson, we're going to investigate reactivity. Reactivity is how much a substance reacts. A substance that is very reactive reacts very fast. We call this a vigorous reaction. My turn, vigorous. Your turn. A substance that is not reactive reacts very slowly or not at all. How do we know that a reaction is taking place? There are three things we might see if a reaction is taking place. These are bubbles forming, a colour change, and a temperature change. Pause the video and write down three things we might see in a chemical reaction. Press play when you're ready to continue. We are going to look at the reactivity of two metals, magnesium and copper. While I'm doing the experiment, I want you to think about these questions. How do we know that a reaction is taking place? Which metal is most reactive? And how do you know? Let's have a look at the reaction between magnesium and acid, and copper and acid. I am going to put some magnesium in this test tube and some copper in this test tube. I'm going to put one piece of magnesium in the first test tube. Have a look, what does the magnesium look like? Magnesium is a silvery-gray solid. I'm going to put one piece of copper in the second test tube. Have a look carefully. What does copper look like? Copper is a orange metal. In my reaction, I'm going to add the same amount of acid. Watch carefully to see what happens when I add the acid to the magnesium. Can you see that it is bubbling very fast? We call this a vigorous reaction. How do I know that a reaction is taking place? I know a reaction is taking place because I can see the bubbles being produced. These bubbles are being produced very fast, so magnesium is a reactive metal. Have a look at copper. I'm going to put the same amount of acid into my copper test tube. What do you notice about the reaction of copper with acid? Can you see any bubbles? Copper is not reacting with the acid. It is not producing any bubbles. Is copper more or less reactive than magnesium? Let's look at them both together. Magnesium is producing lots of bubbles. Copper is not producing any. Which one is more reactive? Magnesium is more reactive because it is forming the bubbles faster. This is an experiment that you shouldn't try at home, so make sure you're watching carefully as I do the experiment. What did we learn in our experiment? We learned that magnesium is more reactive than copper. How did we know that magnesium was more reactive than copper? We knew magnesium was more reactive than copper because it produced bubbles faster. In an investigation, we call the things that we could change variables. What did we change in the experiment we just did? We changed the type of metal. In an investigation, we have three types of variable. Let's find out what they are. The independent variable is the thing you change. What is the independent variable? The independent variable is the thing you change. The dependent variable is the thing you measure. What is the dependent variable? The dependent variable is the thing you measure. The control variables are the things you keep the same. What are the control variables? The control variables are the things you keep the same. In our experiment with magnesium and copper, what was the thing we changed? The thing we changed was the type of metal, so the type of metal was our independent variable. What did we measure in our experiment with magnesium and copper? We measured the number of bubbles produced, so our dependent variable was the number of bubbles produced. Our control variables are the things we keep the same. What did we keep the same in our experiment? We kept the number of pieces of metal the same. We kept the amount of acid the same. Why do you think we needed to keep them the same? When we're doing an investigation, we need to make sure it's a fair test. An experiment can only be a fair test if we only change one thing. In this experiment, we changed the type of metal, so everything else had to be kept the same. Pause the video and write down the three types of variable and what they represent. Let's look at an example. In this experiment, we reacted one gramme of each metal with 20 millilitres of vinegar. We counted the number of bubbles produced for one minute. What was the independent variable? The independent variable is the thing we changed. What did we change in this experiment? The thing we changed was the type of metal. What is the dependent variable? The dependent variable is the thing we measure. What did we measure in this experiment? The control variables are the things that we kept the same. What did we keep the same in this experiment? Pause the video and write down the independent variable, the dependent variable, and the control variables. Press play when you're ready to see the answers. The independent variable was the type of metal. The dependent variable, the thing we measured, was the number of bubbles produced for one minute. And the control variables, the things we kept the same, was the one gramme of each metal and the 20 millilitres of vinegar. We used the same amount of metal and the same amount of vinegar. Pause the video to answer these questions to check your knowledge. Question one, what is the independent variable? Question two, what is the dependent variable? Question three, what are the control variables? Question four, how many variables should you change in an experiment? Pause the video and press play when you're ready to check your answers. The variable you change in an investigation is called the independent variable. The variable you measure in an investigation is called the dependent variable. The variables that you keep the same in an investigation are called the control variables. You should only change one variable in an investigation to make sure it is a fair test. Pause the video to tick or fix your answers. Press play when you're ready to plan our investigation. Now we're going to complete our investigation. If you would like to have a go, you will need some vinegar, water, bicarbonate of soda, a cup, and a spoon. You will also need an adult to help you. If you don't have these things, you can do your experiment with me. Pause the video and copy this table into your notes. Press play when you're ready to start the experiment. Before we start, let's check we know what our variables are. I'm going to read you the method. Then I want you to pause the video and write down the independent variable, the dependent variable, and the control variables. Number one, make the vinegar solution using the correct number of spoonfuls of water and vinegar. Add a teaspoon of sodium bicarbonate to each one, and record the number of bubbles produced in the table. We are going to use the words lots, some, few, many, and none to record the number of bubbles. Pause the video and write down the variables in our experiment. Press play when you're ready to check your answers. The independent variable is the number of spoonfuls of water and vinegar. The dependent variable was the number of bubbles produced. And the control variable was the same amount of sodium bicarbonate. Are you ready to start our experiment? Right, let's get started. I am ready to start my experiment. Can you see how I've set up my page? I've got my four containers that I'm going to do my experiment in, and I've written the values for the amount of water and vinegar next to them. Pause the video and set your page up like mine. When you're ready to start, press play. The first thing we're going to do is make the vinegar solutions using the correct number of spoonfuls of water and vinegar. In the first one, I need to put one spoonful of vinegar and three spoonfuls of water. Here is my vinegar. One spoonful of vinegar and three spoonfuls of water. I'm going to stir it to make sure that it's mixed. In the next one, I'm going to put two spoonfuls of vinegar and two spoonfuls of water. Just stir. In my third one, I'm going to put three spoonfuls of vinegar and one spoonful of water. One, two, three. And one spoonful of water. Stir. And then in my final one, I'm going to put four spoonfuls of vinegar. What's the total number of spoonfuls I've put in each container? I've put four spoonfuls in each container. Why do you think I've done that? I've put four spoonfuls in each container so I knew that each container has the same volume of solution. It is one of my control variables. The next thing I'm going to do is I'm going to add a teaspoon of sodium bicarbonate to each of them. I'm going to write down whether I think that there are some bubbles, few bubbles, many bubbles, or lots of bubbles. I only put one in each one so that I can compare. Oh, can you see that there are more bubbles in the second one than in the first one? That one's reacted even faster. That is a really fast reaction. Can you see how the bubbles are rising? Some, lots, many, vigorous. Now I'm going to convert this into my table. Write the amount of bubbles that we found for each solution under where it says result in your table. You should be able to see that these two reactions are producing many more bubbles than the first two. What can we conclude about the amount of vinegar in our solution and the effect on the reactivity? When there was more vinegar, the reaction was more vigorous. So our conclusion would be that the more vinegar in the solution, the more vigorous the reaction.

Wow! Thanks, Miss Couves. That was so interesting. I loved watching your experiment. Hi everybody, my name's Miss Simkin, and I've just come along to the end of your lesson to help Miss Couves and you to answer some conclusion questions about the experiment that you've just watched or taken part in. So here are your questions. Can you write the answers in full sentences to these questions on your piece of paper that you have? Question one, is this a chemical reaction? How do you know? So what are the signs that it might be a chemical reaction? Question two, what happens to the reactivity as you increase the amount of vinegar? And number three, can you write a word equation for the reaction? Hint, the product, what's produced, the gas in the bubbles, is carbon dioxide. Can you pause the video and have a go at answering those conclusion questions for me now? Great, let's mark our work. If you have a different coloured pencil, you can mark with that. Tick if you got the answer right. And if you need to make any corrections, that's okay. Just do it in your different colour. So number one, you might have written an answer like this. This is an example of a chemical reaction, as a new product was formed, carbon dioxide. We saw bubbles of carbon dioxide in our investigation. If you wrote something similar to that, you can tick it. Maybe you need to add some more in and be more specific that the bubbles that you saw were carbon dioxide. If you need to do that, you can edit your answer with your different coloured pencil now. Question two. As we increased the amount of vinegar, the more bubbles there were. This means that the vinegar solution was more reactive. So if you wrote an answer about the vinegar getting more reactive as the experiment went on, or it being more reactive when you added more vinegar, then you can give yourself a tick. That's the key point there. And then the last question. Here's your word equation. Vinegar + sodium bicarbonate, an arrow to show the product, carbon dioxide. Well done if you got that correct. Great, that's the end of your lesson today. Miss Couves and I are really proud of how hard you've worked. Have a great rest of your day, everybody.

In this lesson, we will learn about what makes our results repeatable and reproducible. We will complete an investigation into the reactivity of metals and analyse our results to see if they are repeatable and reproducible.

What happens when we place metals into acid?

﻿Hello, my name is Miss Couves. I am so excited to be teaching you science today. We have learnt so much in our lessons about chemical and physical changes. Today, we are going to be looking at what happens when we react metals with acids. We are also going to look at what makes our results from experiments repeatable and reproducible. Scientists want their results to be repeatable and reproducible as it means they can be more confident in the conclusions that they make. Let's get started. In today's lesson, we will be looking at what makes results repeatable. Then we will look at what makes our results reproducible. We will end by investigating the reactivity of metals and checking to see if our results are repeatable and reproducible and what conclusions we can make as a result. In today's lesson, you will need an exercise book and a piece of paper, and a pencil. If you don't have one of these items, pause the video and go and get them now. Press play when you're ready to start. Let's start by recapping our knowledge. Pause the video to complete the diagram in your notes. Press play when you're ready to hear the answers. Particles in solids are touching and in ordered rows. In liquids, they're touching and arranged randomly. And in gases, they are far apart, not touching, and moving very fast. As you increase the temperature, particles have? More energy. Let's recap on our knowledge of state changes. Pause the video and write down the four state changes that we have learnt. When a gas becomes a liquid, it's called? Evapo. When a gas becomes a liquid, sorry about that, when a gas becomes a liquid, it's called condensing. When a liquid becomes a solid, it's called? Freezing. When a solid becomes a liquid, it's called? Melting. And when a liquid becomes a gas, it's called? Boiling. What is a physical change? A physical change is a change in the form or arrangement of a substance. Why is paper tearing an example of a physical change? Paper tearing is an example of a physical change because the form of the paper has changed from a large sheet to many tiny pieces. The type of substance hasn't changed. It's still paper. Pause the video and write down why ice cream melting and glass smashing is a type of physical change. What is a chemical reaction? A chemical reaction is a change that forms a new substance. Can you remember three examples of chemical changes? Our three examples of chemical changes were wood burning, cakes baking, and a bike rusting. Let's think about wood burning. When wood burns, it produces carbon dioxide and water. Two new substances have been produced so this is an example of a chemical reaction. What is formed in a chemical reaction? A chemical reaction forms a new substance. Pause the video and write down why a bike rusting is an example of a chemical change. There are three things we might see if a reaction happens. There are: bubbles forming, a colour change, and a temperature change. When a bike rusts, what do we see happen? We see a colour change from the silver metal to a dull orange substance. When metals react with acid, what do we see? When metals react with acid, we see bubbles forming, so we know chemical reaction has taken place. The independent variable is the thing that you'd change. The dependent variable is the thing that you measure. And the control variables are the things you keep the same. In an experiment, how many things can you change? In an experiment, you can only change one thing because you need to make sure your investigation is a fair test. Now let's look at what makes results repeatable. Results are repeatable if the same person gets the same results when they do the experiment again. When are results repeatable? Results are repeatable if the same person gets the same results when they do the experiment again. Pause the video and write down what makes results repeatable. Press play when you're ready to continue. We're going to look at whether these results are repeatable. In this experiment, the scientist is investigating the conditions on a plant's growth. Are these results showing the same pattern? In trial one and trial two, the results are very similar. In trial three, the result for no water seems unusually high. We call this result an anomaly. Scientists ignore anomalies when looking at the pattern. Because the results in the three trials, excluding the anomaly, showed the same pattern, these results are repeatable. The same person has found the same thing when they repeated the experiment. These trials show that a plant with water and sunlight grows more than a plant with no water and no sunlight. What makes these results repeatable? These results are repeatable because the same person has found the same thing when they repeated the experiment. Now let's look at what makes results reproducible. Results are reproducible if a different person gets the same result when they do the experiment. What makes a result reproducible? Results are reproducible if a different person gets the same result when they do the experiment again. Pause the video and write down what makes results reproducible. Press play when you're ready to continue. Let's look at this results table. Are these results reproducible? In this experiment, we can see that three different people have done the experiment. Have they got a similar result? Person A and Person B seem to have very similar results, but Person C seems to be different. It looks like Person A and Person B have reproducible results. But because of Person C, we're not sure of the pattern. What can we do to be absolutely sure? We could ask someone else to try the experiment and see what kind of results they get. Now we're going to do our own investigation into metal reactivity. In order to be able to draw a conclusion, we need our results to be repeatable and reproducible. What does the word repeatable mean? Results are repeatable if the same person repeats the experiment and finds the same thing. What makes results reproducible? Results are reproducible if a different person conducts the experiment and finds the same thing. Pause the video to copy the results table into your notes. Press play when you're ready to start. I am going to do the experiment twice. Why do you think I have decided to do the experiment twice? I've decided to do the experiment twice to check my results are repeatable. I have also asked my friend Kirsty to complete the experiment. Why do you think I have asked her to do the experiment too? I've asked her to do the experiment too to check that my results are reproducible. Are you ready? This experiment is not an experiment that you can try at home. You need to follow me and watch really carefully to see the results that I get. We are doing an experiment to find out about the reactivity of three different metals: magnesium, copper, and nickel. I'm going to react each of the metals with acid and record the amount of bubbles. I am repeating my experiment twice to make sure my results are repeatable. In order to make sure my experiment is a fair test, I am going to have some control variables. I am going to put one piece of metal into each test tube, and then I'm going to add the same amount of acid. I'm putting my magnesium into the first test tube. Oh, might be tricky. Oh, it might be easier with my, let's get to the bottom. Okay! I'm going to add nickel to the second one. Bit tricky to just get one piece on my spatula. There we go. Nickel is in the second one. So I have magnesium in the first test tube and nickel in the second test tube. Finally, I'm going to add copper to my third test tube. Oh, that was much easier, wasn't it? I'm going to add the same amount of acid to each test tube. And watch what happens. Can you see that magnesium is producing lots of bubbles and it's reacting vigorously? Nickel is producing some bubbles but many less than magnesium. Copper is producing no bubbles. It is not reacting with magnesium. It is not reacting with acid. We need to try our experiment again. You should have recorded the results for trial one in your table. Magnesium produced lots of bubbles. Nickel produced a few bubbles. And copper produced no bubbles. Okay, I've cleaned my test tubes so that we can have another go. Remember, we are repeating the experiment so that we can check our results are repeatable. I'm going to add one piece of metal to each test tube. I'm going to put magnesium in the first test tube, nickel in the second test tube, and copper in the third test tube. I'm going to add the same amount of acid to each test tube. Then I'm going to observe and write down my results. If I look carefully, I can see that copper is not reacting with acid. Nickel is producing a few bubbles, but not very many. Magnesium is reacting vigorously with acid. Which of my metals was the most reactive in trial two? Magnesium was the most reactive in trial two. Which was the most reactive in trial one? Magnesium was also the most reactive in trial one. Do we think that our results are repeatable? Our results are repeatable. We found the same thing in both trials. Add Kirsty's results to your table. Did Kirsty find the same thing that we did? Question one, which metal was the most reactive and how did you know? Question two, which metal was the least reactive and how did you know? Question three, were our results repeatable and how did you know? Question four, were our results reproducible and how did you know? Pause the video and answer the questions in full sentences. Press play when you're ready to check your answers. Magnesium was the most reactive metal as it produced the most bubbles. Copper was the least reactive metal as it produced the least bubbles. Our results were repeatable as we found the same pattern in trial A and trial B. Our results were reproducible because our results and Kirsty's results showed the same pattern. Pause the video to tick and fix your answer. Well done for all of the hard work that you've done in this unit. If you'd like to, please ask your parent or carer to share your work on Instagram, Facebook, or Twitter by tagging @OakNational and #LearnwithOak. I have really enjoyed teaching you science in this unit. We have learnt so much about physical and chemical changes, and we've done some of our own investigations. See you next time!

Unit Overview: Physical and chemical changes

National Curriculum

Unit Question

Lessons: