We're about to dive into the wonderful world of waves and take a look at two forms of energy that travel in this way. Light waves and sound waves allow us to experience the world around us through seeing and hearing. But how do they work? Let's find out!

Now It's Your Turn! 

Create some waves using the digital wave model below. Try to test each feature to see what happens. As you do, explore the following questions:

• What happens when you have no damping? What about lots of damping?

• In "oscillate" or "pulse" mode, try changing amplitude and frequency. Based on your results, what do you think amplitude means? What about frequency?

• What happens when you change the tension?

What did the lightbulb say when it was turned off?

I'm de-lighted!

Let's talk about sound:

We'll keep it simple with sound. Here are the three things you need to know:

1. Sound is produced by vibrations and travels through a medium

Example: Normally when you speak, your vocal cords vibrate and send the sound waves through air. If you've ever tried making a telephone with tin cans and string, the string acts as a medium instead of the air, and the vibration of the string transmits the sound to the other can, where it can be heard via someone's ear.

2. The pitch of a sound is related to the frequency. The frequency refers to how many waves occur over a given period of time. If a sound has a long wavelength (where the waves appear wide), only a few waves will fit in a short amount of time, meaning that the sound has a low pitch. By contrast, sounds with short wavelengths can fit many more waves in the same amount of time, giving them a higher pitch. Refer to the diagram below to see what I mean.

3. The volume of a sound is related to the amplitude of the waves, or how tall they appear. A very tall wave refers to a loud sound, while a short wave represents a quiet sound. See the diagram to visualize this concept.

Let's Make Waves - Outside!

It's time to put all of our new knowledge to the test and do some fun experiments with waves.

BEHOLD - the Magic Gong. 

In this activity, you will use a spoon to create amazing sound effects! This experiment is adapted from an activity on Edadventures with kids. Images are below instructions if you need visual clarification. Let's get started...

Step 1: Gather materials. You will need:

• 1 large metal spoon (serving spoon would work)

• 1 smaller metal spoon (tablespoon would work)

• 1 fork (optional)

• Yarn or thick string

• Scissors

Step 2: Cut a piece of string about 4 feet in length. 

Step 3: Tie one of the spoons to the center of the string by the handle.

Step 4: Hold the two ends of the string up to your ears. Press the string down on your ears like you're trying to plug your ears with your fingers. The spoon should dangle down towards your waist.

Step 5: Go outside and swing the spoon gently while holding it to your ears. Swing it into a variety of hard objects, like a fencepost, a tree, a stone, or whatever is around. If you did it right, you should hear a very loud, clear gong sound. 

Step 6: Pull the string away from your ears and tap the spoon on something again. Notice how faint the noise is without listening through string. 

Step 7: Try using the other spoon size and/or the fork. See what happens. You can also experiment with the length of the string. Wow your friends with this awesome new trick!

What was happening? It's simple!

When the spoon hits something, the vibrations of the spoon are transferred as sound waves to two places. 

The first is the air around the spoon. The air allows the waves to travel in many directions, which means anyone in the room can hear the sound of the spoon faintly. 

The other place the waves go is into the string. The string acts as a conductor, which means it allows the sound to travel directly through it. This more direct route to your ears creates a louder, more distinct sound. 

When you changed the size of the spoon or the length of the string, you may have noticed a change in pitch. This is because the shape and size of the components affects the shape and size of the vibrations which you interpret as sound.

Playing with Light - Refraction in Action

This experiment is adapted from the blog "What do we do all day." Images are below instructions if you need visual clarification. Let's give it a try...

Step 1: Gather materials. You will need:

• 1 Glass jar or cup

• 1 Sheet of paper

• 2 Colored markers or crayons

• Water in a different container from the jar

Step 2: Draw two colored shapes next to each other on the paper, side by side.

Step 3: Place the paper against a surface like a wall so it is standing up.

Step 4: Place the empty jar in front of the paper so that you can see the paper through it.

Step 5: Fill the glass with water and notice what happens to the image on the paper as the glass fills. It should reverse and become a mirror image. Check out the pictures below to see it in action:

How did that happen? It's refraction! Light passes through the air to the glass, then refracts as it hits the glass and then the water. This refraction bends the lightwaves toward the center of the glass, coming in to a focal point. After it gets to the center, the light continues to bend as it passes further through the water and the back of the glass. This causes it to bend so much that the light that comes in from the left exits through the right. The light that enters from the right side bends so that is exits on the left. The result is that the visible image appears reversed. How neat!

Review and Reflection

We've covered a lot of material today. Light and sound energy can be quite complicated. Let's review with a few of our main points and reflect on what we've learned. Answer the questions and share them with a friend or family member.

• Light and sound are both forms of energy that travel in waves

• The length of a wave relates to the way in which we interpret it with our senses. 

  • Light waves appear different colors depending on their wavelengths

  • Sounds have different pitches based on their wavelengths and frequencies

• Some animals can see different wavelengths of light from humans. Can you imagine a color that you can't see? Describe your own invented color and where we would find it on the light spectrum.

• Now that we understand how reflections work, what do you think would happen if you lined up a mirror across from another mirror with no objects in between them. What would each mirror show?

• We know that high frequency sounds are high pitched, and low frequency sounds are low pitched. What is the highest frequency sound you can think of?  What is the lowest? It doesn't have to be something you've personally heard before. Compare with a friend.

Quick Quiz

Now that we've studied light and sound thoroughly, it's time to show what you know. When answering these questions about waves, remember that you can always go back and find the answers in the lesson above. Good luck!

About the Author

Rainbow*

There are so many colors of the rainbow, and she likes to use every one! When Rainbow graduated from high school, she went to Kent State University to study fine art, but found that her favorite time of year was the time she spent working at summer camps in between semesters. If you've been to an Ohio Girl Scout camp lately, you've probably seen her there! After earning a BFA in painting and sculpture, she came to Nuhop to work in a camp setting year-round. Her favorite activities are campfires, the high ropes course, and rock climbing.  She can't wait to see the smiling faces of all her campers when they come to Nuhop once again!

*The Nuhop Outdoor Education Staff use "nature names" when working with students. The reason for these nature names is twofold: first it gives them a built-in conversation starter with students, and second, it provides them a level of personal privacy when working with over 4000 students in a given year.