•· Since Valentine's Day is symbolized by hearts, you can demonstrate to students how the heart rate can increase when they exercise. Each student will need a stopwatch and a paper towel tube to use when they listen to each other's heart rates.
Listen through the paper towel tube against a partner's chest for 10 seconds, counting the number of heartbeats you hear. Multiply that number by six to get the number of beats for one minute. Next, have your partner do jumping jacks for 30 seconds. Then, listen through the tube again for 10 seconds, counting the number of heartbeats. Multiply that number by six, then compare the two numbers. You will be able to see that exercise increases how quickly the heart pumps blood through the body.
Heart Water Bottle
•· On Valentine's Day , you can demonstrate how blood pumps through the body by creating a heart water bottle. Fill a squeezable water bottle with water, then add about 20 drops of red food coloring. Insert a straw halfway into the water bottle opening, and use duct tape to seal the straw to the bottle. When you squeeze the water bottle, red water will come up through the straw, demonstrating how the heart pumps blood through arteries in the body.
•· On Valentine's Day, students can turn any color flower into a red Valentine's Day flower. This activity works best with light-colored flowers like white or yellow. Cut off the bottom of the flower's stem. Fill a tall glass with water and add 20 drops of red food coloring. Insert the flower into the red water and leave it there for three days. The red food coloring will flow up through the stem and into the petals of the flower, changing its color to red.