1. Cut the bottle in half (horizontally).
2. Place one of the balloons through the opening of the bottle.
3. Stretch the balloon opening over the bottle opening.
4. Place a rubber band over the balloon to keep it in place.
5. Cut the neck off the other balloon and stretch this balloon across the
bottom of the bottle.
6. Use a rubber band to hold the balloon in place.
7. Using a watch with a second hand record the breathing rate of a person
sitting (1 min.), walking (2 min.), and jogging in place (2 min.).