Cardboard Periscope

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! 🔭

How to Set It Up

Step 1: Prepare Your Tubes

Take two cardboard tubes (kitchen roll tubes work perfectly). If you only have one long tube, ask a grown-up to help cut it in half. Each tube should be about 15–20 cm long. Stand them side by side to make sure they’re roughly the same length. ✂️

Step 2: Cut the Viewing Windows

⚠️ Adult Helper Needed — This step uses scissors to cut cardboard.

On the first tube, cut a small rectangular window (about 3 cm × 2 cm) near one end. On the second tube, cut an identical window near one end. These are your viewing holes — one for your eye and one to let light in at the top! Hold each tube up and peek through the window to make sure you can see through it clearly. 👀

Step 3: Make the Foil Mirrors

Tear off two squares of aluminium foil, each about 8 cm × 8 cm. Wrap each square tightly around a small piece of flat cardboard (cut from a cereal box or similar) that’s about 6 cm × 6 cm. Pull the foil as smooth and flat as you can — the smoother the foil, the better your reflection will be! These are your mirrors! ✨

Step 4: Position the First Mirror

Slide one foil mirror into the bottom of the first tube at a 45-degree angle. The shiny side should face UP toward the viewing window. The mirror should sit diagonally across the inside of the tube, like a ramp. Use small rolls of tape to hold the mirror firmly in place. 📐

Step 5: Position the Second Mirror

Slide the second mirror into the bottom of the second tube at a 45-degree angle, with the shiny side facing the viewing window. Just like the first one, it should sit diagonally across the tube. Secure it tightly with tape. 📏

Step 6: Join the Tubes Together

Stack the two tubes together so that the open ends (the ones without the windows) are touching. Make sure the viewing windows are facing in opposite directions! Wrap tape tightly around the joint where the tubes meet to hold them securely. ⚓

Step 7: Decorate Your Periscope

Use markers, coloured paper, and stickers to decorate your periscope. You could make it look like a sleek black submarine periscope, or use camo colours for a secret spy mission! 🎨

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!