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Indoor activity

Cardboard Periscope

Build a working periscope from cardboard tubes and foil mirrors to spy around corners and over walls like a real submarine captain!

Ages 5-8 0-1 hours Education 8/10

Materials

  • Aluminium Foil
  • Cardboard Boxes
  • Cardboard Tubes
  • Markers optional
  • Paper optional
  • Scissors
  • Stickers optional
  • Tape

Illustrated Steps

1

Prepare Your Tubes

Take two cardboard tubes and stand them side by side. Trim them to equal length if needed — each should be about 15–20 cm.

2

Cut the Viewing Windows

⚠️ Adult Helper Needed. Cut a small rectangular window near one end of each tube. These openings let you look in and let light enter at the top.

3

Make the Foil Mirrors

Wrap aluminium foil tightly around two small squares of flat cardboard. Pull the foil smooth and flat for the best reflection.

4

Position the First Mirror

Slide a foil mirror into one tube at a 45-degree angle with the shiny side facing the window. Tape it firmly in place.

5

Position the Second Mirror

Slide the second mirror into the other tube at 45 degrees, shiny side facing its window. Tape it securely.

6

Join the Tubes Together

Stack the tubes with open ends touching and viewing windows facing opposite directions. Wrap tape tightly around the joint.

7

Decorate Your Periscope

Use markers, coloured paper, and stickers to decorate your periscope with submarine patterns or spy camouflage.

What You’ll Create

Ahoy, Captain! 🚢 You’re about to build your very own periscope — the secret spying device used by submarines to peek above the waves! Using simple cardboard tubes and shiny foil mirrors, you’ll create a real working periscope that lets you see around corners, over fences, and behind furniture without being spotted! 🕵️

Once it’s built, you’ll be able to hold it up and see things that are above your head or hidden around corners — just like a real submarine commander scanning the horizon! This is the ultimate spy gadget! 🔭

Have fun!

  • 🕵️ Go on a ‘spy mission’ around the house and see if you can spot anyone without them seeing you!
  • 🚢 Pretend your sofa is a submarine and use your periscope to scan for ’enemy ships’ (the cat).
  • 🗺️ Use it to peek over tables or around doors during a game of hide and seek.

Why It’s Amazing

  • Physics & Optics: Children learn how light reflects off surfaces at angles to change direction. 🔬
  • Engineering Skills: Building a multi-part device and aligning mirrors develops spatial reasoning. 🏗️
  • Imaginative Play: Encourages storytelling and creative role-play as a spy or submarine captain. 🎭

Pro Tips

For ages 3–5: Focus on the ‘magic’ of the mirrors. They will need a lot of help with the mirror alignment and taping.

For ages 5–8: Encourage them to experiment with the mirror angle — what happens if the mirror is flatter or steeper?

For ages 8–12: Challenge them to make a ‘super periscope’ by adding a third tube section for extra height!