You will need:

• a friend to keep score
• a notebook and pencil
• a watch with a second hand

Introduction:

Depending on what you are doing, you breathe more quickly or more slowly. The speed at which you breathe is called your breathing rate. When you’re asleep, you don’t need much energy. You need less oxygen, and so you breathe slowly. If you’re running in a race, you need plenty of energy, so you breathe more quickly and deeply. See how quickly or slowly you breathe when you are doing different activities.

Procedures:

1. Sit still in a chair for about five minutes, with your eyes closed. After this time, have your friend count how many breaths you take in one minute.

2. Use the watch to measure the time accurately. One inhalation and one exhalation count as one breath. Write down the result.

3. Repeat this counting process after running about 200 feet (60 meters), riding your bicycle, running upstairs, and skipping 20 times. Leave a few minutes between each activity to allow your breathing to settle down.

Discussion:

1. Which activity made you breathe most quickly? When did you breathe most slowly?