The periscope

The idea

A simple periscope has two plane mirrors placed in a Z-shaped box; reflection from the two mirrors lets us see objects that are not visible directly.

Looking out of a bunker

A soldier in a bunker wants to see what is outside without putting her head out.

What do you think is inside a periscope?

• Two plane mirrors
• A tiny lamp
• A pinhole

Look inside

Take each mirror away in turn and see what happens to the view.

Two mirrors in a Z

The light is reflected by the top mirror and then by the bottom mirror. Periscopes are used in submarines, tanks and by soldiers to see outside their bunkers.

A simple periscope has two plane mirrors placed in a Z-shaped box; reflection from the two mirrors lets us see objects that are not visible directly.

Notes

A simple periscope has two plane mirrors placed in a Z-shaped box; reflection from the two mirrors lets us see objects that are not visible directly.

Check yourself

How many plane mirrors does a simple periscope have?

Answer: 2 mirrors

Two plane mirrors, one at the top and one at the bottom.

A simple periscope is a box shaped like a …

Who may use a periscope?

A periscope lets us …

• letter Z — correct. Yes! The two mirrors sit in a Z-shaped box.
• single flat plate. A periscope is a box with two mirrors in it.
• ball. A periscope is a box, not a ball.
• A person riding a bicycle. Periscopes are used in submarines, tanks and by soldiers.
• A soldier in a bunker — correct. Yes! A periscope helps to see outside.
• A person looking at a wall clock. A periscope is for seeing things that are not visible directly.
• make objects bigger. A periscope does not make things bigger. It reflects the light to the eye.
• make objects brighter. A periscope reflects light with two mirrors. It does not make things brighter.
• see objects that are not visible directly — correct. Yes! The two mirrors reflect the light to the eye.