At-Home STEM Activities: Bending Light with Water
Introduction
This week’s Distance Learning theme is optics, light, and the electromagnetic spectrum. In this activity, you will learn how water seems to bend light by taking the shortest path through water. First we will learn a little bit more about how light does this, and then we will test it out on our own!
Refraction is the bending of light. Refraction can happens with sound, water and other waves lengths as it passes from one transparent substance to another. Bending by refraction makes it possible for us to have lenses, magnifying glasses, prisms and rainbows. Even our eyes depend upon this bending of light!
image 1.
Example 1: Light refracts whenever it travels at an angle into a substance with a different density. In this example, imagine that you and your friends are hanging out at the beach. You all decide to go swimming, so you link arms and approach the water in a straight line. As you start walking into the water, you all slow down, pushing through the water, which has a higher density than air. Let’s try this scenario again and this time imagine that you approach the water at an angle relative to the shoreline (see image 1). The person on the end of the line who meets the water first will begin to slow down, then the person next to them, and so on. Because one end of the line slowed down before the other end, the line of people becomes crooked, with the people who are still on the beach at a different angle relative to the water’s edge than the people who have already entered the water. Reference: CC-BY-NC-SA 4.0 license. https://creativecommons.org/licenses/by-nc-sa/4.0/
image 2.
Example 2: When light travels from air into water, it slows down, causing it to change direction slightly. This is because water is denser than air. (Think of the bend in the line of people on the beach and in the water in example 1.) This change of direction is called refraction. When light enters a more dense substance (like water), it “bends”. Image 2 is similar to image 1 in example 1. It shows us that water changes the direction of light because of the vastly different densities.
At-Home STEM Activity
Materials:
Bowl
Coin
Water
Procedure:
Place the coin in the bowl and sit back. You should not be able to see the coin at the bottom of the bowl.
Slowly pour a pitcher of water into your bowl until the coin appears!
Take the Learning Further
Check out this fun video and try out other experiments using light!
Jojo’s Science Show: Top 10 Experiments For Kids with Light and Optics | STEM | Kid science Ep 32
