Spectroscope Rainbow Science

Playing with light and rainbows is a fantastic project for spring and summer. In this easy STEM Project we are making a Spectroscope which is perfect for the classroom or summer camp. As educators, we are always seeking engaging ways to unravel the mysteries of the universe for our students, and what better way to do so than through hands-on projects that ignite curiosity? With this project students will practice their engineering skills and explore the physics of light and color. Ready to play and learn? Let’s go!

SPECTROSCOPE PROJECT

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First let’s talk science so you can build your lesson plans for your kids.

What is Light?

Have you ever wondered what light is made of?

Light is full of colors—even when we can’t see them! Our eyes help us see the world, but they can’t see everything. Tools like a spectroscope help us discover the hidden magic inside light.

When you look at a beam of light, it might seem white or yellow or maybe even blueish, but it is made up of bright patterns of color called a spectrum.

What is a Spectrum?

A spectrum is a range of colors that make up light! When light is split, it shows colors from red to violet—just like a rainbow!

How Does a Spectroscope Work?

A spectroscope is a fascinating tool that acts like a secret decoder to reveal all the hidden colors inside light. It is also known as a spectrograph. The study of light is known as spectroscopy. All the tools used to study light are known as spectroscopic tools.

That is a lot of vocabulary for a really beautiful area of scientific study.

After making a spectroscope, students will understand what a rainbow is, how it is made, and why we see all the colors of the spectrum. They will also get to build their inquiry skills, critical thinking skills and even can put the scientific method into practice.

The Science Rainbows

A rainbow appears in the sky often like magic. But like all great magic, there is some science behind the beauty. A rainbow happens when sunlight passes through tiny water droplets in the sky, that’s why we see rainbows after it rains and there are still droplets in the air. These water droplets act like a prism.

A prism is a 3D shape where both ends are the same size and shape, like two triangles, and are connected by flat sides, bending and spreading light into different colors.

This scientific phenomenon is nature’s spectroscope in action!

The colors of a rainbow always appear in the same order: Red, Orange, Yellow, Green, Blue, Indigo, Violet. A fun way to remember the colors of the rainbow is to memorize the name: ROY G. BIV!

How Does a Prism Work?

White light from the sun is made up of all these colors mixed together. When it hits water droplets, the colors separate, creating a rainbow and making it easy for our eyes to see each line of color!

Spectroscopes and Periscopes and Kaleidoscopes Compared

If you have spent any time here at STEAM Powered Family, you have probably seen our Pool Noodle Periscope project and our Kaleidoscope Project (both really fun projects… just in case you are looking!) They have similar sounding names but are actually very different. Let’s explore the differences between kaleidoscopes, periscopes and spectroscopes.

Periscopes help you see over or around objects (they are great for spying!). They work by using mirrors to bounce light so you can see things that are hidden from your view. Submarines use periscopes to look above water without coming up!

Spectroscopes split light into colors to create rainbows. They work by using a prism or diffraction grating to spread out light, like a rainbow. Scientists use spectroscopes to study stars and planets! Which makes this a great project as part of a unit study on space, the stars, universe and planets.

Kaleidoscopes are a popular childhood toy that makes colorful changing patterns when you look inside. It works by using mirrors and small colored objects (like beads or glass) to reflect light and create patterns. The word “kaleidoscope” comes from Greek and means “beautiful shapes to see!”

Spectroscope Tutorial Video

Now we have explored the science, take a minute to watch the tutorial video. It is always so much easier to watch the process before you attempt it with your students or even by yourself to make a prototype for the class. If you can’t see the video, it is being blocked by a firewall or adblockers, head over to the STEAM Powered Family YouTube Channel to watch it there.

Making a Spectroscope for Kids

Before you start, I highly recommend grabbing the templates. They are available simply by signing up to our newsletter list. If you are already a member, simply enter your email to unlock the printable templates.

Materials & Tools

Large Pringles can
Old CD
Glue
Electrical tape
Masking tape or scotch tape
Scrap piece of a postage box or cereal box
Ruler
Pencil
Scissors
Craft knife
Exacto knife
Black spray paint or acrylic paint

Directions

Spray, paint, or cover the inside and outside of the Pringles can in black. Set it aside to dry.

Why black? We need it really dark and to block any light or reflected light.

Remember to grab the printables

Print out both pages of the template. Start by cutting out the large strip on the first page of the template and the circle with the slit on the second page and trace it onto your small piece of cardboard and cut it out. Use scissors to cut out the circle and the craft knife or Exacto knife to cut out the slit.

Paint or spray the circle black on both sides. Set it aside to dry.

Wrap the large strip of paper around the Pringles can, making sure that the word “top” is facing the top of the can. Match up the two rectangles at the ends of the strip and tape in place, using two pieces of tape. Use the third piece to tape the top of the front of the can so it does not slide around.

Special Note

The strip is made to fit my Pringles can. You may need to adjust the sizing to fit your can as sizes could be different around the world. The important thing is that the two rectangles for the eye-piece make a square. Students may need the help of an adult for this.

Use an Exacto knife to cut the square at the back and the slit on the front, in short small cuts. Do not try and do it in one cut.

Safety Note

REMEMBER TO KEEP YOUR FINGERS AWAY FROM THE BLADE WHEN CUTTING WITH A CRAFT KNIFE OR EXACTO KNIFE!

Remove the paper strip when done.

Push the CD into the slot with the reflective side facing the Pringles tube. Make sure you push the CD into the slot until it touches the end of the slot on both sides.

Pro Tip!

Go slow and careful with these next steps to ensure you block all light.

Cut a piece of electrical tape long enough to cover the whole slit as we need to block all the light from getting into the tube.

Stick the tape onto a surface that you can cut on and make small slits on both sides of the tape. This makes the tape easier to tape on a curve.

Stick the first tape onto the top of the CD and then repeat these steps for the other side of the CD. Use the side of the scissors to push the tape right up against the tube. Tuck in and stick down any extra length of tape.

Put a line of glue around the top of the tube and stick the circle down to close the tube.

Very Important Step

Make sure that the slit on the lid is in line with (parallel to) the CD and the eye-piece otherwise your spectroscope will not work properly.

Let the lid dry and then stick a piece of electrical tape around the top, leaving half of the tape sticking up. Use the scissors to make little snips all the way around and then stick each little piece down, one after the other.

Fun learning moment

Wow, students just learned a clever little trick to stick any kind of tape down around a curve, so that it lies flat!

The spectroscope is done and ready for kids to explore different sources of light like a scientist! Take the spectroscope to a light source and look through the eye-piece and you should see a rainbow. Take a peek inside ours!

Spectroscope Science Experiment

Using the Spectroscope to Explore Different Types of Light Sources

Now that the spectroscope is ready, let’s do some experiments.

How do different light sources affect a spectroscope?

One really interesting experiment is to test different types of light to see what hidden mysteries they possess. But before you do that with the kids, let’s look at and understand all types of light sources.

Sunlight (Natural Light)

The sunlight makes a full rainbow because the sun gives off all colors of light and there are no spaces between all the colors.

Incandescent Bulb (Filament Bulb)

An incandescent bulb is a light bulb that glows when a tiny wire inside it gets very hot. It makes a warm, yellowish light that has more red and yellow tones. It also makes a full rainbow, like sunlight.

Fluorescent Light (Tube Lights)

Fluorescent lights are tube-shaped lights that glow when special gases inside them are powered by electricity. They are brighter and use less energy than old light bulbs. These tubes show bright lines at specific colors instead of a full rainbow.

LED Light (Modern Bulbs)

LEDs are small lights that glow when electricity passes through them. They are bright, last a long time, and use little energy. Some LEDs have almost full spectrums, while others show gaps in certain colors.

Neon Lights (Signs)

Neon lights are similar to fluorescent lights. They show only a few bright lines in red, orange, or yellow, and the pattern they make depends on the type of gas inside the light.

Candle Flame

Candle flames make a spectrum similar to an incandescent bulb, but weaker. They show warm colors like red, orange, and yellow.

Troubleshooting Your Spectroscope

If your DIY spectroscope isn’t working, here are some simple ways to fix it!

No colors or a very faint spectrum?

Check the slit: The opening (slit) should be thin and straight. If it’s too wide or uneven, use two razor blades or black tape to make a thin, clean gap.

Use a bright light: Try a strong light source like a fluorescent bulb, LED, or the Sun (but never look directly at the sun).

Do your colors look blurry?

Adjust the angle of the CD: The shiny side of the CD/DVD should be facing the slit at the right angle. Try tilting it slightly until the colors appear clearly.

Check for dirt: Wipe the CD with a soft cloth to remove dust or fingerprints.
There is no rainbow, just random light?

Make sure the light goes through the slit: The light must pass through the slit before hitting the CD/DVD. Shine the light straight at the slit.

The tube is too bright inside?

Make it darker: Cover any holes in the box to block extra light. A darker inside makes the colors show up better.

Is it still not working?

Try a different light source: Some LEDs and dim bulbs don’t show a full spectrum. Try using a fluorescent light or sunlight reflected off a white surface.

Have fun making spectroscopes with your class and learning all about light and rainbows!