The pinhole camera
A tiny hole makes an upside-down picture.
A card with a tiny hole
Put a candle on one side of a card with a tiny hole, and a screen on the other side. A teacher does this activity.
What do you think appears on the screen?
What this lesson covers
The idea
A pinhole camera is a device in which light rays from an object pass through a tiny hole and form an image on a screen; the image is upside down (inverted).
A card with a tiny hole
Put a candle on one side of a card with a tiny hole, and a screen on the other side. A teacher does this activity.
What do you think appears on the screen?
- An upside down image of the flame
- An upright image of the flame
- Nothing at all
Follow the rays
Make the tiny hole and follow the rays from the top and the bottom of the flame. The candle is only a picture.
Inverted image
The rays cross at the hole. So the image on the screen is upside down.
A pinhole camera is a device in which light rays from an object pass through a tiny hole and form an image on a screen; the image is upside down (inverted).
Notes
A pinhole camera is a device in which light rays from an object pass through a tiny hole and form an image on a screen; the image is upside down (inverted).
Check yourself
In a pinhole camera the light rays pass through …
The image of a candle flame in a pinhole camera is …
Where is the image of the flame formed?
The ray from the top of the flame reaches the screen at the … of the image.
- a mirror. Mirrors reflect light. In a pinhole camera the rays pass through a hole.
- a tiny hole — correct. Yes! That is why it is called a pinhole.
- a sheet of cardboard. Cardboard is opaque. The rays pass through the hole in it.
- turned sideways. The image is upside down, not sideways.
- upright. The image is upside down.
- upside down (inverted) — correct. Yes! The rays cross at the hole.
- On the screen — correct. Yes! The rays make the image on the screen.
- On the pinhole. The rays pass through the hole. The image is on the screen.
- Behind the candle. The image is formed on the screen, on the other side of the hole.
- middle. The ray from the top of the flame lands at the bottom of the image.
- bottom — correct. Yes! That is why the image is upside down.
- top. The rays cross at the hole, so the top of the flame goes to the bottom.