Pulse-o-Meter

What you need:

• Play dough

• 1 toothpick

• Timer

What you do:

1. Roll a dime sized amount of play dough into a ball

2. Press the ball gently on a table to flatten the bottom

3. Take the toothpick and press it into the top of the play dough so that it sticks straight up

4. Rest your forearm on a table with your palm facing up

5. Place the play dough Pulse-o-Meter on your wrist, just under your thumb. You will start to see the toothpick move slightly with the beating of your heart.

6. Set your timer for 10 seconds. Count the number of times the toothpick moves during those 10 seconds.

7. Then, multiply your count by 6 to determine the beats per minute, which is your pulse!

Questions to ask:

1. Why does the toothpick move your wrist?

2. Where else can you feel your pulse?

What's the science:

Your heart is an organ, made mostly out of muscles, that pumps blood through your body. It is about the size of your fist and located in the center of your chest, though it sits slightly to the left. Your heart works like two pumps. The right side of your heart receives blood from the body and pumps it to the lungs to receive oxygen. The left side of the heart receives that oxygen-rich blood from the lungs and pumps it out to the body. The pumping motion of the heart is called your heart-beat or pulse.