HEARTBEAT

PURPOSE : To observe the vibration of a match due to the pulsation of blood in the wrist.

MATERIALS : Modeling clay
                            Paper match

PROCEDURE :

• Insert the match onto a very small piece of clay ( the smaller the better )
• Flatten the bottom of the clay.
• Place your wrist, palm side up, on the table.
• Place the clay on your wrist, and move the clay around on the thumb side of the wrist until the match starts to slowly vibrate back and forth.
• Count the number of vibration that the match makes in one minute.

RESULTS :  The match vibrates back and forth with a regular beat. For adult it will vibrate 60 to 80 times in one minute. The vibration for childern is from 80 to 140 beats per minute.

WHY ? As the heart contracts, blood is forced through the blood vessels. The blood moves at a rhythmic rate causing the blood vessels in the wrist to pulsate. All blood vessels have this throbbing motion, but the vessels in the wrist are close to the surface of the skin and can be felt more easily. The movement of the blood under the clay causes it and the match to vibrate.