Make Your Own Periscope and Kaleidoscope

Make Your Own Periscope and Kaleidoscope

These two classic optical toys are straightforward to make at home using everyday materials. Both rely on mirrors reflecting light at angles, but they produce quite different results. A periscope lets you see around corners or over obstacles by bouncing an image down a tube to your eye. A kaleidoscope turns simple objects into symmetrical patterns through multiple reflections.

Children who enjoy hands-on projects will find these satisfying to build and use. The science behind them is simple enough to explain as you go, making them useful for home education or just a rainy afternoon activity.

Both projects involve cutting with sharp blades and handling mirrors that may have sharp edges. An adult may wish to handle the knife work or supervise closely depending on the child's age and experience. Glass mirrors should be taped around the edges before use to reduce the risk of cuts.

What You Will Need

For the periscope:

• Two small flat mirrors of the same size, available cheaply from craft shops
• A long thin cardboard box or an empty milk or juice carton
• Scissors and a craft knife
• Strong tape such as parcel tape or duct tape
• A pen or pencil for marking
• A ruler

For the kaleidoscope:

• Three narrow mirrors or strips of mirrored card, roughly the same length
• A cardboard tube such as a kitchen roll inner or a postal tube
• Clear plastic or acetate for the viewing end
• Translucent paper or greaseproof paper
• Small coloured beads, sequins, or broken pieces of coloured plastic
• Tape and scissors
• Card for end caps

Mirrored card, sometimes called silver board, is stocked by many craft suppliers and works well for the kaleidoscope. It is easier to cut than glass mirrors and safer for younger children to handle. If you cannot find it locally, online craft retailers usually carry it.

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Building the Periscope

Start with your box or carton. If using a cardboard box, tape the ends shut firmly and consider reinforcing the whole thing with tape to make it more rigid. A juice carton will usually be sturdy enough on its own, though you might wish to cover it with paper or tape for a neater finish.

The periscope needs two viewing windows cut at opposite ends. One window goes near the top on the front face, the other near the bottom on the back face. Hold one mirror against the top of the box, about a centimetre down from the edge, and draw around it. Cut this rectangle out with the craft knife, keeping the hole slightly smaller than the mirror so it can rest against the edge.

Turn the box around and repeat at the other end, on the back face. You should now have two windows positioned diagonally opposite each other.

The mirrors need to sit at 45 degree angles inside the box, positioned so they face each other. This angle is important because it bounces light through exactly 90 degrees, redirecting your line of sight from horizontal to vertical and back again. The simplest method is to cut small diagonal slots in the cardboard to slide the mirrors into. Alternatively, tape the mirrors in place at an angle. Hot glue or additional cardboard bracing will help keep them secure and correctly aligned.

Test the periscope by looking through the bottom window. You should see whatever is in front of the top window. If the image is upside down or unclear, adjust the mirror angles until the view looks correct.

Once everything works, seal any gaps with tape and decorate the outside.

Building the Kaleidoscope

The kaleidoscope works by reflecting images between three mirrors arranged in a triangular tube. Light enters one end, bounces between the mirrors, and creates symmetrical patterns from whatever objects are placed inside.

Cut three mirror strips to the same length, slightly shorter than your cardboard tube. Tape them together along their long edges to form a triangular prism, with the reflective surfaces facing inward. Slide this mirror assembly into the tube.

For one end of the tube, cut a circle of card with a small central hole to serve as the eyepiece. Tape or glue it in place.

The other end requires a few more steps. Cut a circle of clear plastic to fit the tube opening, then cut a slightly larger circle of translucent paper. Place your beads, sequins, or coloured fragments on the clear plastic disc, then lay the translucent paper over the top. Tape or glue this assembly to the end of the tube, creating a sealed chamber that allows light through while keeping the objects contained.

When you look through the eyepiece and rotate the tube, the loose objects will tumble and the mirrors will multiply the image into repeating patterns. Holding the kaleidoscope toward a window or lamp will make the colours appear brighter and the patterns sharper, since more light passes through the translucent objects.

Experiment with different objects inside. Transparent and translucent items often work better than solid opaque ones, as they let more light through.

Once finished, gather up any cardboard scraps or mirror offcuts and dispose of them carefully, especially pieces with sharp edges.

Both projects can be adapted once you understand the basic principles. Longer periscopes, wider kaleidoscopes, or different mirror arrangements will all produce different results, and make good starting points for further exploration of how light and reflection work.