Heartbeats

Grade Levels: 2 - 4

Excerpted from Science Surprises! Ready-to-Use Experiments and Activities for Young Learners.

OBJECTIVE
Students experiment with pulses to learn more about the human body.

MATERIALS

Clock with a second hand or a stop watch.

PROCEDURES

1. Have the children make their hands into fists. Explain that there's something in their bodies the size of their fists; it works like a motor and pumps blood to all parts of the body.
   
2. Demonstrate where the heart is, and help the children find it on the left side of their chests. Ask the children to find the veins in their wrist. What's inside their veins? Where else on their bodies do they have veins? Why do they need veins?
   
3. Does your heart work harder when you're resting or exercising? By checking your pulse you can find out how many times your heart beats.
4. Help the children find their pulses by having them place their index and middle fingers of their right hands on their left wrists. Count the number of times the pulse beats in 15 seconds. (Older children can multiply by four to determine how many times it beats per minute.)
   
5. Next, ask the children to stand up and run in place or do jumping jacks for a minute. Have them sit down again and check their pulses. Compare the pulse rate before and after exercise.

EXTENSION QUESTIONS

• Why is it important to exercise? Make a list of all the things children can do to get exercise.
  
• Why is it also important to rest? When you exercise your heart has to pump faster to supply more energy to your body.