Ever looked at a straw in a cup of water and wonder why it looks bigger and appears to be bent? Or look at something underwater and wondered why it looks so big? These are all a result of the bending of light or refraction. In today’s science experiment on the refraction of light, we’re going to take a closer look at how light bends.
What is refraction?
Refraction is the bending of light. This occurs when light travels through one material to another (ex: air, water, etc…) Unlike objects that reflect, objects that refract light look different. For example, when looking at a glass of water with a straw in it, the straw may appear to be broken. This happens because light moves more slowly in water than in air. As a result, the light bends as it passes from air to water, making the straw appear to be bent.
Materials for light refraction experiment:
- glass jar, container, or vase
- paper (or use the FREE printable Valentine message from down below)
- marker (to write your message if you’re using paper)
STEP 1: Fill the glass jar almost to the top with water.
STEP 2: If creating your own “secret message” fold the paper in half. Then write your message on one side of the paper. Make sure to write the message backward from right to left. You can create a second message on the back of the folded paper. To make things even easier, you can always download the Free Valentine printable from down below. It’s already done for you!
STEP 3: Next, place the glass jar on a flat surface. Place the folded paper about 3-4 inches behind the jar filled with water.
STEP 4: Looking through the front side of the glass of water, look at your secret message. What do you see?… Your message is not much of a secret anymore!
How does this refraction experiment work?
During the experiment, light travels from the secret message, through the air, through the glass, through the water, then through the glass again, and through the air one more time before finally reaching your eyes.
When light travels through different materials such as the glass jar, air, or water, it travels at different speeds. This causes the light to refract.
Light waves travel faster through the air than they do through water or glass because the air is less dense. It then slows down a little when traveling through the water and is at its slowest, when passing through the glass jar. This is what causes the light to refract or bend and make the secret message change direction. As a result, the message is no longer a “secret” and can be read.
The light that is refracted through the glass of water also acts as a magnifying glass. It makes the image appear larger than it really is. Try moving the image closer to the glass jar and see what happens.
If you like kid-friendly science resources and want to learn more about light energy & the other forms of energy, check out my complete energy unit perfect created with kids in mind.
… and if you’d like to use the “secret” messages I used above for the refraction lab, you can download it for free here.
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