Year 3 Science: Light sources
Part of the Year 3 Science light and shadows chapter. Chapter overview · whole chapter on one page
Light sources
A light source is something that makes its own light. The Sun, a torch and a lamp are light sources.
Most things do not make their own light. We see a book, a chair or a cup because light from a light source reaches them, and bounces off them into our eyes. They are not light sources.
| Thing | Makes its own light? |
|---|---|
| Sun | yes |
| Torch | yes |
| Lamp | yes |
| Book | no |
| Chair | no |
| Cup | no |
Key ideas
- A light source is something that makes its own light.
- The Sun, a torch and a lamp are light sources.
- A book, a chair and a cup are not light sources.
- We see things that are not light sources when light from a light source bounces off them.
Method. Count the rows that say yes in the column Makes its own light?
- Read the column. The Sun, the torch and the lamp say yes.Sun, torch, lamp
- Count them. There are three light sources in the table.3
- Write the answer. 3
Check. The three things that say no are the book, the chair and the cup. ✓
Method. Think about whether a chair makes its own light.
- Look at the table. The chair says no in the column Makes its own light?no
- Decide. A chair does not make its own light, so it is not a light source.no
- Write the answer. no
Check. We see a chair because light bounces off it. ✓
Method. Think about what gives us light in the day.
- Think about the sky. In the daytime, the bright light in the sky comes from the Sun.the Sun
- Write the name. That light source is the Sun.Sun
- Write the answer. Sun
Check. The Sun makes its own light. ✓
Watch out
Watch out: the Moon is not a light source. It shines because it reflects light from the Sun.
Try it at home or school (with a grown-up). With a grown-up, walk round your home. Find three things that make their own light, and three that do not. Only switch things on and off with a grown-up. Do not touch a lamp bulb that has just been on, because it can be hot. Never look straight at a very bright light.
Exam tip
Grown-up tip. Ask: “Does this thing make its own light? How can you tell?” Let your child use the words light source, and check the answer by switching the thing on.
Exercise 8B Light sources
Method. Find the thing in the table that is in the sky.
- Read the table. The Sun says yes in the column Makes its own light?Sun
- Write the answer. Sun
Check. The Sun is a light source. ✓
Method. Think about whether a cup makes its own light.
- Look at the table. The cup says no in the column Makes its own light?no
- Write the answer. no
Check. We see a cup because light bounces off it. ✓
Method. Think about the things in a room that make light.
- Think about the room. A lamp and a torch both make their own light.lamp or torch
- Write the answer. Accept any one of: lamp, torch.
Check. Both make their own light. ✓
Method. Count the rows that say no.
- Read the column. The book, the chair and the cup say no.book, chair, cup
- Count them. There are three things that are not light sources.3
- Write the answer. 3
Check. The Sun, the torch and the lamp make their own light. ✓
Method. Think about which one makes its own light.
- Think about each one. A book does not make its own light. A torch does.torch
- Write the answer. torch
Check. A book reflects light; a torch makes its own light. ✓
Method. Find the things that make their own light.
- Check each thing. The sun, the torch and the lamp make their own light.sun, torch, lamp
- Check the rest. The book, the chair and the cup do not make their own light.not light sources
- Write the answer. Accept any order of: sun, torch, lamp.
Check. Three things are light sources, and three are not. ✓
Method. Read the key idea in this section.
- Read the key idea. A torch is a light source, because it makes its own light.source
- Write the answer. source
Check. A light source makes its own light. ✓
Method. Think about where the light from the Moon comes from.
- Think about the Moon. The Moon reflects light from the Sun, so it is not a light source.reflects
- Write the answer. false
Check. The Sun is the light source. ✓
Method. Think about why we can see a book.
- Think about the light. We can see a book because light from a light source bounces off it.bounces off
- Decide. So the book is not a light source.false
- Write the answer. false
Check. Being seen does not make something a light source. ✓
Method. Think about what a light source does.
- Think about the test. A light source makes its own light, even in the dark.own light
- Write the step. So put the object in a dark place and see whether it gives its own light.in the dark
- Write the answer. Accept any step that says to switch the object on, or to see whether it gives its own light in the dark.
Check. Only the object should change in the test, so keep everything else the same. ✓
Method. Think about the light from the torch.
- Follow the light. The torch makes light, and it lands on the book.lands on the book
- Decide. The light bounces off the book and enters your eyes, so you can see it.yes
- Write the answer. Yes. Accept any reason that says light from the torch bounces off the book into your eyes.
Check. The torch is the light source, and the book is seen by reflected light. ✓