| MadSci Network: Anatomy |
Chico, You can show your classmates how the heart works by using a living organism or by building a mechanical model. If you want to demonstrate how the heart works by using a living organism you can use Daphnia, the water flea. Your teacher may know where to obtain some or you may be able to obtain some live ones at a pet or aquarium store. They use them as fish food. Water fleas are semitransparent so their beating heart is easily observed with a stereoscopic (dissecting microscope). You can also observe them with a compound microscope under low power. It will help if you add protoslo to the water when you are observing them. This will cause them to move slower so you can see them better. There are some experiments you can do on the heart rate of Daphnia. First, observe their heart rate in water that is at room temperature. Then place some of them in cool water and some in warm water and compare their heart rates to the ones in the water at room temperature. Remember, they are ectotherms (cold blooded). You can also place some in water that contains ethyl alcohol and some in water that contains nicotine to alter their heart rate. To see other student's results of these experiments go to: http://www.ipfw.edu/Cm1/HOVERSLA/Web/I%20Don%27t%20Know/Daphnia.htm To do a mechanical demonstration of how the heart works you will need a syringe with a one-way valve to represent the heart, some clear plastic tubing to represent blood vessels, some colored water to represent blood and a t-tube connector. Connect the plastic tubing to two ends of the t-tube, make sure the tubing is filled with colored water then connect the syringe to the other end of the t-tube. When you squeeze the syringe (heart) you will be able to observe the colored water (blood) circulating through the plastic tubing (blood vessels). I hope these ideas help you with your project. Good luck with your presentation. Robert Houska Mad Scientist
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