Experiment to Measure the Speed of Sound in Air

1. Stand a measured distance from a building with a large, flat wall. Try to have no obstacles in the way.
2. As a trial, clap two wooden blocks together. An echo is heard: this is the clapping sound traveling to the wall and reflecting back at you. Clap repeatedly in time with the echoes (clap – echo – clap – echo etc.). Once a constant rhythm is achieved…
3. Have someone begin timing as you clap 51 times, stopping time on the 51st clap.
4. To calculate the speed of sound, divide 2x the distance to the wall by 1/50th the time for the 50 claps (the 51st is not included because that is when the stopwatch stopped timing).

Experiment proving that exhaled air contains more carbon dioxide than inhaled air

(A, B and C refer to the tubes unless specified)

Close end of B. Breathe in. Air from atmosphere enters through A, passes through limewater and enters your mouth (cannot enter through B because closed).

Open end of B and close end of A. Breathe out. Exhaled air passes through limewater in test tube B and exits through B.

Limewater in test tube B (which contained the air you exhaled) turns milky much faster than in test tube A (which contained the air you inhaled).