Information about Create coloured shadows! with Fizzics Education | Kids Science Experiments

Make Coloured Shadows

Make Coloured Shadows

Follow FizzicsEd 150 Science Experiments:

You Will Need:

Three Strong flashlights.

Red, blue and green cellophane

Three rubber bands

A clean white board or wall

A dark room

Optional: A magnifier for focussing the light.
Note: If you can get your hands on some red, green and blue spotlights, use them instead of the torch and cellophane.

Create coloured shadows science experiment - materials needed
1 Create coloured shadows science experiment - red cellophane over a torch

Place the red cellophane over the flashlight so that the light is coloured red. Secure with a rubber band.

2 Create coloured shadows science experiment - three torches with red _ blue _ green cellophane

Repeat the process, so that you have a ‘green flashlight’ a ‘blue flashlight’ and a ‘red flashlight’ to use.

3 Create coloured shadows science experiment - red green and blue spotlights

Shine all of the flashlights onto the wall, angle all the torches until you see a faint white light on the wall.

4 Create coloured shadows science experiment - coloured shadows behind hand

Try placing object in front of the lights to make shadows. What colours do you make? Why?

5 Create coloured shadows science experiment - magnifying focusing red green and blue light

Try placing a magnifier into the lights to form an image on the white screen of the lamps! As you move the magnifier closer to the white screen you should be able to show that the individual coloured light images converge and then mix together.

Why does this work?

White light is comprised of all of the colours of the rainbow i.e. the light spectrum.
it is very easy to see this using a glass prism, just like Sir Isaac Newton did in the 1600’s

Combining the three different colours should have produced a small white area on the wall.
This is called colour addition i.e. adding up to white light. You used red, green and blue light as they are the primary colours of light.

Your object creates areas where the light from each flashlight cannot pass.
As each flashlight is shining from a different angle some light can still reach the wall, creating coloured shadows. Try pointing a rod or stick in the middle of the focused 3 lights… you should see a magenta, cyan and yellow colour which are the secondary colours formed from the red, blue and green primary colours of light.

Learn more!

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