Does Sound Travel Through Solids?

Concepts

• Sound travels through solids, liquids, and gasses. 
• Matter through which sound travels is called a medium.
• Solids such as wood, steel, and string are good sound media.

The following activities will demonstrate that sound can travel through solids and that sound travels better through solids than gasses (air).

Materials

• desk(s)
• 2 cups per pair of students
• string
• pencil

Directions - Activity 1

• Ask the students to predict if sound can travel through a solid (such as a wood or metal desk).
• Ask the students if they think sound travels better through air (a gas) or wood (a solid).
• Have a student(s) listen as he/she taps 2 fingers on a desk.
• Have the student(s) repeat the tapping but this time place one ear on the desk.
• What did he/they notice? Which sound was louder? (the 2nd time).
• Have the students explain the results. (Sound did travel through a solid. Sound traveled better through the solid than through the air.)

Directions - Activity 2

• Ask the students to predict if sound can travel through string (a solid).
• Have the children construct a cup and string telephone.

                   Use a pencil to poke a small hole in the bottom of each cup.
                   Push one end of the string into each cup and tie a large knot on the        
                   inside of each cup.

• Have both children stand a few feet apart and hold the string taut between them. Have one child talk into his/her cup as the other child puts his/her cup up to his ear to listen.
• Ask the students what they concluded from the activity. Did the string (a solid) carry sound vibrations?
• The students can also repeat this experiment with a loose string to see if it will work.