Tuesday, October 19, 2010

Biology: Carbon

This week we talked about carbon and how its atomic structure gives it so much versatility in forming chemical bonds with other elements. Using the latest in electron microscopy we were able to produce this incredible image of an actual ethane molecule.

Next time we meet we'll investigate the major carbon-containing macromolecules that make up all living things.

Sunday, October 17, 2010

Physics: Quiz-boards

This week the kids started to build quizboards.

What's a quizboard? A quizboard is a game in which you try to match up questions with the correct answers. If you succeed, a light bulb turns on, and if you get the question wrong, nothing happens.

Interesting child psychology fact: When I do this activity, it is almost always the case that kids suggest adding features to the quizboard that will punish players with a beep or even a shock for wrong answers. Not your kids! Not only do these guys understand electrical circuits, but you can rest easy knowing they are far more forgiving (read less cuckoo) than your average kid.

As of today the kids have written their quizzes and started building and insulating the wires that will connect questions and their respective answers. Next time we meet they will complete their quizboards and bring them home.

Thursday, October 14, 2010

Biology: More on water

This week we continued our discussion on why water is special and necessary for life. We compared how tap water, sea water, and air respond to changes in temperature. The obvious answer is: put things on the stove they get hot, put things on ice, they get cold. What's less obvious is that not everything heats and cools at the same rate, and not everything freezes and boils at the same temperature.

In the ice bath, the test tube with water and sea water cooled more slowly than the air. On the stove our results were somewhat less consistent. What we know from our more experienced collegues is that water is both relatively hard to cool and hard to heat,remaining a liquid over a wide range of temperatures. And as we discussed last week, liquid water is what it takes for life as we know to exist.

Monday, October 11, 2010

Physics: Circuits

This week we experimented with different kinds of circuits. The kids learned about the basic parts of a circuit: battery, load, and wires, and then they were challenged to build and diagram circuits that could turn on lights, motors, and annoying beeping machines. What's that saying...necessity is the mother of invention? Following their success with the annoying beeping machines, we introduced the concept of switches. Ah....sweet silence.

Wednesday, October 6, 2010

Physics: Charge your batteries!

First day of physics seemed like a great time to charge up our batteries. We started off by examining some batteries, taking note of things like voltage, size, and the fact that every battery has a positive and a negative terminal. After a brief discussion about what batteries are and how they work, the kids made batteries out of grapefruit, potatoes, and strips of copper and zinc. Using a multimeter we confirmed that our batteries worked. A single grapefruit or potato has a voltage of around 1 v, which compared to your 1.5 v AAs is no small potatoes! We attached wires to the battery, hooked up an LED, and NOTHING. Apparently 1 v is not enough voltage to power an LED. But, when life gives you lemons,make lemonade, or in my case, when life gives you a grapefruit tree, make several grapefruit batteries in series and voilà! Let there be light!