Sound occurs by vibration, or when an object moves back and forth rapidly. Second grade children are old enough to begin understanding this concept. This experiment can be used with a lesson on Alexander Graham Bell, the inventor of the telephone.
You will need the following supplies to complete this experiment:
- 2 small metal cans
- 2 large metal cans
- Kite String
- 1 Nail
- Teacher or Parent
- 2 students
Sounds All Around Us
Starting the Experiment
Follow the steps below to discover how sound works:
- Give your students a short lesson on sound and vibrations. Read to them the story of Alexander Graham Bell. You can also give your students some hands on demonstrations with violin or guitar strings. Show your students that you can actually see vibrations in action. Place a piece of paper over a speaker and turn up the volume. The paper will jump up and down as the music (sound) in the speaker comes out. This is a great reference leading in to the experiment.
- Get two small metal cans and open completely on one end with a can opener. If you are using a can that has already been eaten and washed out then you are ahead a step. If your cans are full of food you will need to empty them in to storage containers and eat them within the next few days. Then clean out your cans with some soap and water.
- Turn your cans upside down so that the open end is flat against the table. Place a nail in the middle of the can and use your hammer to drive the nail in to the can. Then use the hammer to remove the nail from the can. Do this to both cans. A teacher or parent should do this step as it can be very dangerous for a second grader to do. Second graders are usually only 7-8 years old.
- Get out your kite string and make it long enough to give you a little distance. Cut the string and thread one end through each of the can holes. Tie a big knot so that the string doesn't come loose.
- Have one student stand at each end with a can. Have student number one talk in to the can while student number 2 listens in to the can. Did student number 2 hear what student number 1 said. Have each of the students take turns listening and talking in to the cans.
- Now repeat this process with some larger cans. Take one end off of each can, place a hole in each can, and thread the string through each hole. Now have the students try using the bigger metal can phone. Did it work better or worse?
Try different sized and shaped cans to determine which of them effects the sounds. Do any of them make the sounds more clear or louder?
You should also try different kinds of string. See if yarn works, or fishing line. Are any of them better or worse at carrying the vibrations from one can to the other?