OUTREACH : 50-min. HANDS-ON WORKSHOPS : Physics of Light and Sound

All we see and hear come together as one in this workshop. Discover the similarities between sound and light.

Michigan Grade Level Content Expectations, Science, 2007

• Identify light and sound as forms of energy. (P.EN.03.11)
• Relate sound to their sources of vibrations. (P.EN.03.31)
• Demonstrate that light travels in a straight line and that shadows are made by placing an objec in a path of light. (P.EN.03.21)
• Demonstrate what happens to light when it travels from water to air. (P.EN.03.22)
• Explain how we need light to see objects: light from a source reflects off objects and enters our eyes. (P.PM.05.52)

Physics of Light and Sound Pre-visit Vocabulary

Absorb: To take in or become part of.

Energy: The capacity to do work.

Gas: A state of matter where the molecules are loosely packed, taking up the entire space of their container.

Liquid: A state of matter between solids and gasses where the molecules spread out to take the shape of the bottom of their container.

Molecule: The smallest particle of any substance that retains the same characteristics.

Reflect: To bounce off of, as from a mirror.

Refract: To pass through an object while changing direction and velocity.

Solid: A state of matter where all the molecules are tightly packed, resulting in a rigid shape.

States of Matter: The physical arrangement of molecules in a substance or object. There are three main states of matter.

Vacuum: Completely empty space.

Vibration: Rapid back-and-forth movement of molecules.

Physics of Light and Sound Post-visit Activity

Post-visit activities provide your students with an opportunity to review workshop-presented concepts and introduce related subjects. Below you will find a classroom extension activity and a list of suggested resources for further exploration. We hope that you enjoyed our Outreach Hands-On Workshop and we look forward to visiting your students again!

Hands-on Activity: How Fast Does Sound Travel?

Materials

• A drumstick or pole (something to hit the object with)
• A large outdoor space

Procedure

1. Bring the class, large drum (or noise-maker) and stick outside on playground or field.
2. Teacher or student volunteer should move about the length of a football field away 100-120 yards with the noise maker of choice.
3. Strike the object. Make your movement dramatic to ensure that the group is seeing your movement AND hearing the vibration of the noise maker.
4. Students should write down observations then share.

Discussion

Sound travels through air at about 340 meters per second. Light, however, travels at an astounding 300,000 meters per second. At close range, this is hardly noticeable. For instance, when you are standing close to your friend talking, you see their lips move at the same time that you hear them. As the distance increases, you begin to notice that there is a slight delay between the light and the sound. Picture lighting and thunder. First, you see a big flash of lighting in the sky. Then, you wait. Sometimes, it takes a long time for the sound to reach you. The further away the lighting actually is, the longer it’ll take for the sound to reach you.

Challenge your students to figure out some math. If somebody standing 340 meters away strikes a drum, how long does it take for the sound to reach you? The answer to this is easy: 1 second. Simply divide 340 by 340. Now, how long does it take for you to see it? To do this, you would have to divide 340 by 300,000 — about 1/1000th of a second!

Now, for more challenging problems:

• If you hear thunder 5 seconds after you see lighting, how far away was the bolt?
• If a bright light flashes out in space and takes 45 seconds to reach the earth, how far away is it?
• If your friend strikes a drum 100 meters away, how long does it take you to hear it?

Suggested Resources

Books

Glover, David. Sound and Light. Kingfisher Books. 2002.
Levine, Shar and Leslie Johnstone. Science Experiments with Sound & Music. Sterling. 2002.
Maton, Anthea. Prentice Hall Science: Sound and Light. Pearson Prentice Hall. 1997.
Trumbauer, Lisa. All About Light. Children’s Press (CT). 2004.

Internet

Science — Sound & Light
ZOOM activities
Science of Sound: Hands On Activities
Light Science Activities for Kids