Year 6 Science: A pinhole and an upside-down image
Part of the Year 6 Science light travels in straight lines chapter. Chapter overview · whole chapter on one page
A pinhole and an upside-down image
A pinhole camera is a box with a very small hole in the front. Light from each point of an object travels in a straight line through the hole, and lands on the screen at the back.
- Light from the top of the object lands at the bottom of the screen.
- Light from the bottom of the object lands at the top of the screen.
So the image is upside down. This happens because light travels in straight lines.
Key ideas
- A pinhole camera makes an image using straight lines of light.
- Light from the top of an object lands at the bottom of the screen.
- The image is upside down.
- Never look at the Sun through a pinhole camera.
Method. Follow the straight line.
- Follow the ray. The ray from the top of the object goes through the hole in a straight line.straight line
- Name the place. It lands at the bottom of the screen.bottom
- Write the answer. bottom
Check. The ray crosses at the hole. ✓
Method. Think about the rays.
- Think about the rays. Light from the top of the object lands low on the screen.lands low
- Write the answer. So the image is upside down.upside down
- Write the answer. upside down
Check. The image is upside down because light travels in straight lines. ✓
Method. Look at the picture.
- Look at the picture. The small hole is in the front of the box.front
- Write the word. So the hole is in the front.front
- Write the answer. front
Check. Light enters the box through this hole. ✓
Watch out
Watch out: a pinhole camera is never used to look at the Sun. The light from the Sun is very bright and can damage the eyes, even through a pinhole.
Exam tip
Exam tip. Describe a pinhole image with straight lines: the top of the object goes to the bottom of the screen, so the image is upside down.
Try it (with your teacher, or a grown-up at home). Make a simple pinhole viewer from a shoebox with a hole in one end. Look at a lit object indoors, such as a lamp, through a tracing paper screen at the other end. Never point the box at the Sun, and do not look through it at the Sun.
Exercise 7D A pinhole and an upside-down image
Method. Follow the straight line.
- Follow the ray. Light from the bottom of the object goes through the hole in a straight line, and goes up.up
- Write the word. So it lands at the top of the screen.top
- Write the answer. top
Check. The image is reversed. ✓
Method. Think about the rays.
- Think about the rays. Light from the top of the object lands at the bottom of the screen.bottom
- Write the answer. So the image is upside down.upside down
- Write the answer. upside down
Check. The image is reversed top to bottom. ✓
Method. Look at the picture.
- Look at the picture. The hole is in the front of the box, facing the object.front
- Write the answer. front
Check. Light enters through the front. ✓
Method. Read the labels.
- Read the labels. The image appears on the screen at the back of the box.screen
- Write the answer. screen
Check. The screen is at the back of the box. ✓
Method. Use the idea of straight lines.
- Use the idea. Light travels in straight lines, so the ray goes straight through the hole.straight
- Decide. So the answer is yes.yes
- Write the answer. yes
Check. The straight-line path explains the image. ✓
Method. Check the rays.
- Check the rays. The top of the object lands at the bottom of the screen.bottom
- Decide. So the image is upside down, and Ruby is not right.no
- Write the answer. no
Check. Light crossing at the hole makes the image upside down. ✓
Method. Follow the rays.
- Follow the rays. Light from the bottom of the tree lands at the top of the screen.top of screen
- Write the answer. So the top of the screen shows the bottom of the tree.bottom of the tree
- Write the answer. bottom of the tree
Check. The image is reversed. ✓
Method. Think about how the image forms.
- Think about the light. The image forms because light travels in straight lines through the hole.straight lines
- Decide. So the light does not bend, and Priya is not right.no
- Write the answer. no
Check. Straight lines explain the image. ✓
Method. Think about the rays.
- Think about the hole. A bigger hole lets in more rays from each point of the object.more rays
- Make the prediction. The rays overlap, so the image is brighter but blurred.blurred
- Write the answer. Accept any prediction that says the image becomes brighter but less sharp, because more light enters at different points.
Check. Test the prediction with a grown-up, using a torch and a lamp. ✓
Method. Think about crossing rays.
- Think about the top. Light from the top of the object goes straight through the hole, down.down
- Think about the bottom. Light from the bottom goes up, so the image is inverted.inverted
- Write the answer. Accept any sentence that says light from the top of the object crosses the hole and lands at the bottom of the screen, so the image is inverted.
Check. Straight rays cross at the hole. ✓
Method. Think about one ray from each point.
- Think about a small hole. A small hole lets through a narrow beam from each point.narrow beam
- Think about sharpness. So each point makes a small spot on the screen, and the image is sharp.sharp
- Write the answer. Accept any sentence that says a small hole lets through one ray from each point, so the image is sharper.
Check. A large hole blurs the image. ✓
Method. Think about the Sun.
- Think about the Sun. The Sun is very bright, and its light can damage the eyes.damage
- Think about the hole. A pinhole does not make the light safe, so the Sun must never be looked at through it.never
- Write the answer. Accept any sentence that says the Sun is very bright, and light passing through a pinhole can still damage the eyes, so it must never be used.
Check. Never look at the Sun, in any way. ✓