The next body system we learned about was the Circulatory System. We started by watching The Magic School Bus Works Out DVD, while the kids ate lunch.
The RSO lab for this unit involves making a model of blood. They recommend using corn syrup for plasma, red hot candies for red blood cells, lima beans for white blood cells, and dry lentils or yellow peas for platelets. Well, I always seem to change these around based on what I have available so, of course I did again. We actually didn’t have any of the above items in the house and since they are not items we would normally use, I didn’t want to go out and buy them just for the experiment.
Instead I used water with yellow food coloring for plasma, strawberry fruit snacks for red blood cells (they actually were shaped almost exactly like our description says red blood cells are – round, flat with a slight indentation in the middle), and small, very old round cake decorating candies for platelets. Those are the parts that worked okay.
What didn’t work so well was using some very old, stale mini marshmallows for white blood cells. When I added them to our jar, a bunch of powdery white stuff came off and turned our plasma all murky. So, I rinsed it out and tried again using white pompoms for our white blood cells. This was actually a much better idea since white blood cells are a lot larger than red blood cells. They did work much better but I think I added too much yellow food coloring the second time since our white pompoms turned yellow almost immediately. I also didn’t rinse the jar out well enough because things were still somewhat murky.
Oh well, the kids enjoyed it and seemed to get out of it what they were supposed to. George did a nice job on the lab sheet naming the parts by what they do.
We then tried to see our pulse by putting a toothpick through a marshmallow and resting in on our wrists. They were unable to hold still enough to actually balance the marshmallow on their wrist, so instead I had them feel for their pulse in the underside of their jaws. Both were able to feel it that way.
We read about the Circulatory system in our Science Encyclopedia, in our Scholastic Kid’s Encyclopedia: Science and in two books borrowed from the library: A Drop of Blood and Your Blood and Its Cargo. The second book was a little too involved for them but they liked the first one, although they kept asking why the guy in it was a vampire.
We finished up with watching some videos. Kids Biology. com had a brief video of a beating heart. George prefers the videos at Kids Health. org. They are on the silly side but contain good information, and are about 2 1/2 minutes long.
We also watched Schoolhouse Rock – Circulation on youtube. George thought it was pretty funny, liked the music, and had to shake a leg when they talked about your foot going to sleep.