Refraction of Light Experiment

For an easy and engaging science experiment, try this refraction of light experiment! Kids will be amazed to watch the arrows magically switch directions as they perform this fun science trick.

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Light Refraction Experiment Using Arrows

You will only need a few supplies for this experiment and you probably already have them! In this trick, kids can observe how the water makes their arrows appear as if they are switching directions through light refraction.

You could also play around with different colors, shapes and words to see how they change when water is added into the cups.

Watch the Video Tutorial!

The Science

Here’s what you will observe: As you pour the water into the glass, the arrow will appear like it is magically switching directions.

When light passes through one transparent thing into another (for example: from air through to glass and water) it undergoes what is known as refraction. Refraction happens because light travels at different speeds in different materials (such as air and water). The light bends when it enters the water and then bends again when it leaves the water. This bending of light causes the image to appear flipped in our eyes.

Note: The distance of the arrow to the cup can play a role in whether you see the arrow flip. If the arrow does not flip, you may need to adjust the distance of the arrow to the cup (either closer or further away).

Follow-up experiments: Try doing this experiment again by changing some of the variables. See what happens when you change the image. Or change the colors. You can also experiment with different liquids. Or try filling the glass halfway!

Supplies Needed

• 2 clear glasses
• 2 pieces of white cardstock or paper
• Black marker
• Water
• Small bowls or another object to prop the paper on

How to Make the Arrows Reverse

1. Cut out two square pieces of paper.

Using a black marker, draw an arrow on each piece of white cardstock.

2. Prop the pieces of cardstock up against a small bowl or another small object.

Place the arrow about 12 inches back from the glass. If you do not see the arrow flip, you may need to adjust the distance of the arrow to the glass (either closer or further away depending on your position).

3. Arrange the arrows so they are facing opposite directions for two arrows.

You can also do this experiment with just one arrow.

4. Fill the glasses with water.

For an arrow facing left without water, it will flip to face right once the water is added in.

Kids will be amazed to see the arrow flip directions while learning about light refraction!