This quiz will test your knowledge from the previous lesson and your prior learning.

Revision: Which particle is transferred when insulators are charged by friction?

What did Benjamin Franklin hypothesise in his famous 'kite experiment'?

What invention happened after his kite experiment?

What is a spark?

By what process is charge built up in a cloud?

Case Study - Benjamin Franklin and Sparks

﻿Hello everyone, and welcome to today's science lesson with me, Miss Walrond. Today, we're going to be learning about electric fields. So please make sure that your phone is now turned to silent and that you've removed any distractions from around you. Where possible, see if you can find yourself a nice quiet place to work. And when you're ready, let's get started. In previous lessons, we have been learning about static electricity, how objects can become charged. And today we're going to learn more about the electric fields that surround these charged objects. So we're going to start off with electric fields around positively charged objects. We're then going to move on to look at the electric fields around negatively charged objects. And lastly, we'll take a look at the electric field diagrams between two charged objects. For this lesson, you're going to need a pen and a paper, but also a pencil and a ruler for the drawing of these electrical field diagrams. Please pause the lesson now, if you need to go and collect any of these items. Okay, let's get started. So we're going to begin by looking at drawing electrical field diagrams for positive charges. Please don't write anything in this section. There'll be some pause points or independent tasks for you to complete at the end. You might, well, have already seen some field diagrams, whether this is gravitational fields, when perhaps you were looking at gravitational potential energy or magnetic fields, the fields around magnets. Electric fields are very similar. Electric fields show us the force that is felt around a charged object. For an object to have an electric field, it has to be charged. Neutral objects just don't have these fields. Here is a diagram for the electric field around a positive charge. Pause the lesson now while you have a good look at this picture. The electric field tells us something about the force that would be felt on another charged object, if it is in the vicinity of this positively charged object. If we look at this diagram, we can see that the force that is felt is strongest closest to the positive charge. We can tell this because if we look in a small area box close to the charge, we have a lot of field lines. Here there are four field within this box that I've drawn. But as we move further away from the charged object, the electrical field decreases. This means the force that will be felt on another charged object would be smaller. Here's another box further away from the charged object. Here we can see fewer field lines in this box. There are only two. If the field lines become more widely spaced, this means there is less force acting. Now let's take a look at the direction of the field lines. You should be able to see that they are all pointing away from the positive charge. This is because we have a convention with electric field diagrams that they will show us the direction of the force that would be felt on a positively charged object. So if we brought another positively charged object close to this positively charged object, they would repel. This means that all of the field lines have to point away. The force that will be felt on our test positive charge would be a repulsion, pushing it away from the positive charge. Okay, let's try some quickfire questions then about this type of field. For each of these questions, I would like you to give me a thumbs up, if they are true, or a thumbs down, if they are false, I'll read the statements out to you and then give you a count of three to make up your mind. So the first statement, the electric field is strongest closest to the charged object. Three, two, one, thumbs up. This statement is true, and we can see this because there are more field lines closer together near to the charged object. Next question, all objects have an electric field. Three, two, one, thumbs down. This one is a false statement. Only charged objects will have electric fields. Next question, the field is weakest furthest away from the charged object. Three, two, one, thumbs up with this one. This is a true statement. As we move further away from the charged object, we see the field lines move further apart. This tells us the force is weakest. Next statement, the field lines point in the direction of the force that a positively charged object would feel. Three, two, one, thumbs up, this one is a true statement. Our field diagrams are drawn showing the direction of the force on a positively charged test object. Okay, now it's time for a little pause point. Please pause the lesson now while you complete the questions on your screen. Great work everyone, please pause the lesson again now so that you can mark your answers. Okay, great work so far, everyone. Let's move on now and take a look at what the electric field diagrams will look like around negative objects. Here you can see a field diagram for a negative charged object. Pause the video here while you take a good look at it. What's similar and what is different to the positive charge diagram? Excellent, so you should have noticed that the shape of this electric field is identical to the shape of our positive charge field diagram. We can see that all the lines are still radial and that if we look at the field closest to the electrical charge, the force that would be felt is strongest. This is because we have more field lines closer together if we are closer to the charge. But if we move further away, we can see that the number of field lines in the same area decreases. This means that the force that would be felt is weaker. A difference though, between these two sets of diagrams, is that the direction of the force that would be felt. Because by convention, electric field diagrams show us the direction of the force that would be felt on a positive test charge, we see that all of these arrows point in towards the negative charge. This is because the positive test charge would be attracted to our negative charge. Therefore, all of the lines will point inwards. Let's take a look at some quickfire questions about a field diagram around a negatively charged object. Okay, these are true or false statements again. So please give me a thumbs up if they're true, thumbs down if they are not. First statement, electric field lines point away from negative objects. Three, two, one, thumbs down for this one. The field lines would point in towards the negative object, not away from it. Electric field lines point towards negative objects. Three, two, one, thumbs up for this one. So we know that the electric field shows us the direction of the force that would be felt on a positive charge. And we can tell that there's going to be an attractive force between the positive charge and a negative object. Next statement, electric field lines show the direction of the force felt by a positively charged particle. Three, two, one, thumbs up for this one. This is true, again. Now it's time for another pause point. Please pause the lesson now while you complete the questions on your screen. Excellent, everyone, please pause the lesson again now while you mark your answers. Now it's time for an independent task. Please pause the lesson now while you complete the sentences on your screen. Great work, everyone. Please pause the lesson again now so that you can check your answers. Add in any extra detail as needed. Fabulous, we're now going to move on to take a look at what the electric field diagrams would look like between two objects. Previously, we've looked at the field diagrams around a positively charged object and the field diagram around a negatively charged object. We're now going to combine those ideas all together. As before, please don't write anything in this section. There'll be some pause points or independent tasks for you to complete at the end. Pause the video here to take a look at this field diagram. What does it show? Excellent. So when we look at this field diagram, we can see that we've got a positively charged plate at the top of this diagram, and we've then got a negatively charged plate at the bottom. The pink lines here are representing our field, and we can see that the electric field is pointing from the direction of the positive plate to the negative plate. This is because if we placed a positively charged particle in between these two plates, it will be repelled away from the positive plate and attracted towards the negative plate. So there will be a force acting on it in the downwards direction. We can tell something extra from this diagram then. Because all of these field lines are straight lines, and evenly spaced, this tells us we have a uniform field. A uniform field just means that the force that would be felt on our positively charged test particle is the same at all points inside the field. Okay, let's complete some quickfire questions, true or false statements again, to test your understanding so far. First statement, parallel lines show a uniform field. Three, two, one, thumbs up, this would be true. Here we have got evenly spaced and straight lines. These would be parallel lines, so this statement is true. A uniform fields has a non-constant force. Three, two, one, thumbs down for this one. We know that uniform fields show constant forces, not non-constant forces. The field lines point from negative to positive. Three, two, one, thumbs down. Remember, our field lines have to show the direction of the force on a positively charged particle. This would mean that it would be repelled from positive and attracted towards negative. So they run positive to negative. Okay, everyone, now it's time for some independent tasks. Please pause the lesson now while you copy and complete these field diagrams. Excellent, everyone. Please pause the lesson again now so that you can mark and check your answers. Make sure that you've drawn your field lines with a ruler. Okay, everyone, a different type of tasks in part two. Please pause the lesson now, copy the field diagrams and identify whether these plates are positive or negative. Great work, everybody. Please pause the lesson again now so that you can check your answers. The last part that I want to look at before the end of the lesson is non-uniform electric fields. Here you can see the field diagram between a positively charged object and a negatively charged object. These aren't plates, they're small spherical particles. Here we can see that the field diagram looks quite a lot like the field diagram between two bar magnets. We have a greatest force found in between the two charged objects. We can see this because the field lines are closest together here. But note which direction the field lines run. They always travel from positive to negative, as they're showing which way the force will be felt on a positively charged object. Pause the lesson now while you complete the tasks on your screen. Excellent, everyone. Please pause the lesson now so that you can mark your answers. Great work today, everyone. We have successfully learned about electric fields. You should not be confident in drawing the electric field around a positively charged object, a negatively charged object, between two plates. Remember, that's our uniform fields, and between two point charges, that's our non-uniform field. All that's left for you to do now is to complete the worksheet and the exit quiz. I hope you have a great rest of your day. Take care, bye everyone.

This quiz will test your knowledge from this lesson and your prior learning.

Revision: When a negatively charged object and a positively charged object are brought close together what happens?

Which two statements below describe how to increase the electric field?

You are observing the electric field around a positive charge. Which way does the field point?

You are observing the electric field around a negative charge. Which way does the field point?

Which of these statements best describes where we find electric fields?

Electric Fields

Draw the electric field pattern for isolated charged spheres

Explain how the concept of electric fields help explain non-contact forces between charged objects, sparking and other electrostatic phenomena

In this lesson we will be learning about electric fields. We will learn how to draw field diagrams and how to interpret them.

Physics

Y10 Physics

Key Stage 4

Year 10

Miss

Electric fields

Electricity

UNIT

Drawing electrical circuits

Charge and current

Potential difference

Electrical resistance

Resistance of a wire

Series circuits

Parallel circuits

Series and parallel circuits

Properties of resistors

Filament lamps

Diodes

Light dependent resistors

Thermistors

Review of electrical circuits

Domestic electricity

Electrical power (Part 1)

Electrical power (Part 2)

Multi-Step calculations

The national grid

Domestic electricity review

Static electricity

Case study: Benjamin Franklin and sparks

Revision: Two identical resistors (10 Ω) are connected in series. What will be their total resistance?

What does this electrical symbol represent?

What does LED stand for?

In which direction is conventional current said to flow?

Which component is used to measure the current in a circuit?

What is the unit of measure for current?

Which of these equations is the correct equation linking charge, current and time?

If 450 C flow through a desk lamp in 9 seconds, what is the current?

Which statement best describes the potential difference in a series circuit?

If two 3 V cells are added in series, what is the battery potential difference?

Revision: What is the unit of charge?

Which equation links energy transferred, charge flow and potential difference correctly?

A resistor has a potential difference of 12 V across it and a current of 0.2 A flows through it. What is its resistance?

Revision: What colour is the neutral wire in a 3 pin plug?

What is the unit of power?

Which equation correctly describes the relationship between power, current and potential difference?

Complete the sentence: In a series circuit the current....

Complete the sentence: In a series circuit the total potential difference must equal...

Which of these is the definition for resistance?

If the resistance of a series circuit is increased and the cell voltage remains the same, what will happen to the current?

Why does the resistance increase as the potential difference increases for a lamp?

Lesson overview:Electric fields

Electricity: