Model Heart

Time: 10 minutes

What you need:

• 2 pint sized jars

• Red food coloring

• 1 balloon

• 1 rubber band

• Scissors

• Skewer or toothpick

• 3 plastic bendy straws

What you do:

1. Fill one pint sized jar 2/3 full of water and add red food coloring so it looks like blood.

2. Cut off the "neck" part of your balloon and then stretch the balloon over the top of the jar.

3. Put the rubber band over the balloon and tightly secure it to the jar.

4. Take the skewer or toothpick and poke two small holes in the top of the balloon—1 inch apart from each other.

5. Stick your plastic bendy straws into each of the holes, with the bendy part sticking out the top.

   Tip: You can place another straw into one of your straws to extend it even further!

6. Place your second pint sized jar under the straw on the left side.

7. Pinch the top of the straw on the right side to close it like a valve.

8. Push down on the balloon to see blood pump through the model heart.

   Tip: The average heart beats 60-100 times per minute. Practice pumping the blood at a similar rate.

   
   

What's the science:

The heart is the body's hardest-working muscle that beats 100,000 times a day to transport blood all around the body. A human heart has four chambers. Deoxygenated blood enters the heart in the right atrium, travels through the right ventricle and then toward the lungs to pick up oxygen. It is then pumped back to the heart into the left atrium and through the left ventricle to be transported to the rest of the body. In our model heart, the pinched straw acts as a valve that keeps the blood pumping in the same direction. In your heart, that valve actually opens to let more blood into the chamber and then quickly closes so the blood is pumped to the rest of the body.