Wednesday, October 28, 2009

Bodies: Lesson 4 - Heredity

First of all, thanks to everyone for bringing your family tree and pictures with the kids - we enjoyed seeing who your kids take after!

I first asked the kids to tell me about things their bodies do. I was informed that our bodies eat and jump and that our hearts beat. I asked them if they knew that we also use our bodies to make new people? They've all seen pregnant women, of course, but how does that work?

For those who had trepidation (none of you seemed to) - fear not! The mechanics of how exactly the embryo gets its start didn't come up with our kindergartners. You'll all have to forge those waters on your own.

We looked through a beautiful book on fetal development that Lynn brought, from sperm-meets-egg to the end of gestation. Then we talked about how the mom is not just the carrier of the baby, but that her body or, more specifically, her DNA, gives the baby half of its characteristics, and that the Dad's sperm has the DNA to give the baby the other half.

For the record, I totally did not mean for that to look like a naked lady.

We did an exercise where we tried to guess whether a baby's eyes would be blue or brown by looking at what color the parents' eyes are. Of course, we all know that the picture is a lot more complicated than that - Pat and I have hazel and blue eyes, respectively, and we have two brown-eyed children - but it gave a flavor for how genes get passed on. Maybe I should have done Mendel's wrinkled pea experiment instead :)

Next we got out our pictures and talked about the families we came from. This was Jack's family tree:

We also talked about how Sarah and Fiona have the same DNA, but that other kinds of twins are just like regular brothers and sisters.

Finally, we sat the kids down and had them make DNA strands out of foam sheets and pipe cleaners. Then the kids started a little pipe cleaner jewelry enterprise, and Jack started to make pipe cleaner ninja stars. It was all good!

We ended the session with more tag. One of these days we'll make up a game that actually goes along with the lesson. Until then... onward and upward!

Bodies: Lesson 3 - Microbes

On October 8, we met to discuss germs and microbes. We started off the session by talking about how our bodies are made of cells, but that cells are too small to see without strong microscopes. Although we can't see most cells with our at-home microscopes, we did look at hair, fingernail clippings, and tooth guk, provided by an accommodating Lily. Which is not to imply that I thought she had more to share than anyone else, she was just the most willing to let me scrape her teeth. :)

While three kids looked at the microscopes and drew what they saw, the other three drew what they thought germs looked like.

Next we decided to collect some germs and grow them in a petri dish in an agar medium. To show that cleaning does eliminate germs, we took two samples from each area - one before and one after cleaning it.

Our samples came from:

The Toilet - before (section 1) and after cleaning (section 2)

The garbage can - before (section 3) and after cleaning (section 4)

Under a fingernail (section 5) and after cleaning (section 6)

Apparently I'm not so great at growing germs, though - I intended to show them the colonies of bacteria the next week, but nothing grew, I think because I kept the petri dish in a place that's too cold. We'll try again sometime and see if we can grow some nasty bugs.

Then I showed them pictures of and we talked about the kinds of germs we're most likely to meet: bacteria, viruses, and fungi. We compared the kids' drawings of germs to pictures of real germs, and I have to say, the kids' imaginations meet the reality pretty well!

Fiona's looked to me most like a staph infection:

Jack, Caiden and Spencer drew germs that looked like bacteria:

Lily drew a scary-looking virus:

And Sarah was into the fungi:

And keep in mind that they drew these before I showed them the pictures of the real germs! Pretty creative! We also talked about how to keep germs at bay.

The last 15 minutes we played "sneeze tag" on the front lawn. It's kind of like regular tag, except that we call it sneeze tag. Yeah, I was too lazy to make up rules, so sue me.

Thanks, everyone, for another fun week!

Thursday, October 1, 2009

Bodies: Lesson 2 - Nutrition and Exercise

Another fun afternoon with your kindergartners today!

We started off with a tray full of mysterious substances and a discussion about which foods are healthy. The kids already seem well-versed in what's good for us, and why. Good for you guys and the kids' schools for drilling that message home! Then we demonstrated what makes up your food, namely:

* carbohydrates (played here by a bowl of sugar for simple carbs and another of oat bran for complex carbs)
*fats (vegetable oil)
*protein (represented by an egg)
*vitamins (Vitamins C and E)
*minerals (table salt and iron filings)

(Click on the photos to see them in more detail)

After pouring things into other things to see what dissolves in what (while making evil scientist cackling noises), we made lava lamps - pour water in cup, layer cooking oil on top, then add food coloring. The dye will not dissolve in the oil, but will not be heavy enough to break the surface tension keeping it from dropping into the water... until you drop some salt on top of it, which will drag the dye down with it.

Caiden and Heather gave a beautifully illustrated and orchestrated talk about carbohydrates, insulin, and diabetes,

And then he demonstrated how he uses a super poker ("It doesn't hurt!") to test his blood sugar.

Last, he showed us his insulin pump, which he uses when his sugar is off or when he's about to eat.

Finally, we talked about fitness and its relation to your heart rate. Everyone got to listen to his or her heart (Thanks to my nurse friend Leanne for the loan of the stethoscope).

Next, everyone drew pictures of themselves resting and exercising.

We measured their heart rates at rest,

did some exercise,

And measured again.

It went up! Resting and exercise numbers were recorded on their charts.

Thanks to Heather and Becky for their portions of the instruction, and for helping while the kids played mad scientist with the "chemicals!"

Next week we'll talk about germs - microscope time! Does anyone have one to loan? I have one, but it would be nice to have a few, if possible.

And remember that in two weeks we're going to talk about heredity. It would be great if the kids could bring in a family tree, perhaps going back to their great-grandparents (or farther, if you're so inclined), and if you have pictures of your relatives and ancestors that you can paste onto them, even better - we'll look for family resemblances!