At-home STEM Activities: DIY Kaleidoscope
We’ve all witnessed the reflection of light. Looking at ourselves in the mirror, seeing sunlight bounce off a pool of water, observing the moon—we can witness all of these because light is reflecting off of a surface.
The salar de uyuni in bolivia is the largest salt flat in the world. When it rains a lot, the flats flood, turning it into a giant mirror. (Image via lufthansa magazin)
Light always reflects in the same way, following the Law of Reflection. Basically, the law of reflection says that when light hits a flat mirror, it will reflect at the same angle that it hits the mirror.
The initial ray of light, called the incident ray, hits the mirror at an angle. We measure this angle from the “normal line,” which is a line that is perpendicular (90 degrees) to the mirror. The resulting light is the reflected ray. The incident angle and the reflected angle have the same measure.
We can use this law to manipulate light to make beautiful images inside a kaleidoscope! Let’s use some recycled material to make our own kaleidoscopes.
DIY Kaleidoscope
Material:
Cardboard tube (like one from a roll of paper towels or toilet paper)
Paint (optional)
Clear plastic (we’re using the lid from a container of greens)
Ruler
Permanent markers
Straw
Button or bead (optional)
Craft knife
Hot glue gun and glue sticks
CD
Tape
Kids, make sure you have an adult’s permission and supervision when using potentially dangerous tools, like the craft knife and the hot glue gun!
Instructions:
1. Cut the cardboard tube so it is 3 inches long. (Optional: paint and decorate your cardboard tube)
2. Measure the diameter (the width across) the cardboard tube. Draw a circle on the clear plastic with a radius (half the distance across) of the cardboard tube’s diameter.
3. Cut out the plastic circle. Use the permanent markers to decorate your plastic circle. You can also paint a light layer of white paint on the back of your plastic circle, to make the designs easier to see.
note: we removed the circle we drew in the previous step using a little bit of rubbing alcohol. you can do that too if you want to erase the circle you drew once you cut it out!
4. Use the craft knife cut out a small circle in the middle of your plastic circle. You want this cut-out to be big enough for the straw to fit through.
5. Measure and draw three 1 in. x 2.5 in. rectangles on the CD. Cut out the rectangles.
6. Tape the three rectangles together to form a triangular prism with the reflective side of the CD on the inside of the prism.
7. Cut open your cardboard tube and glue one corner of the mirrored prism inside. Continue until all the corners are glued. Glue the cardboard tube back together.
8. Glue the straw to the cardboard tube, with about an inch of the straw hanging off one end of the tube. Cut the straw if needed. Place the plastic circle on the straw. To keep the circle on the straw, either glue a button or bead to the end of the straw or place a ring of glue around the end of the straw so the circle can’t slip off.
Your kaleidoscope is done! Hold it up to a light and look through, turning the plastic circle to change what you can see in the kaleidoscope.
How does a kaleidoscope work?
When light enters the kaleidoscope, it will follow the law of reflection, bouncing off the mirrors. Because there are multiple mirrors forming a mirrored tunnel, the light will bounce between the three mirrors and down the tube, as shown in the two diagrams below. This forms the the multiple images that you can see in the kaleidoscope.
