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.

General Science: The Right Stuff

This week the kids were charged with designing a spacesuit that could withstand the intensely high temperatures one might find on Venus. Lacking the funding to actually travel to Venus and not wanting to violate the Helsinki Declaration,* we used ice-pops instead of people and hot water instead of Venus. The kids made spacesuits using one of three available materials: tin foil, wax paper, and bubble wrap. Once outfitted with their spacesuits, each ice pop was submerged in a pot of boiling water for one minute. For comparison we also had a control ice pop, meaning an ice pop with no space suit. After a minute the kids opened up each ice-pop and measured how much of it had melted by pouring the liquid into a graduated cylinder. Of the 3 materials, bubble wrap was the best insulator.

*ethical principles for research on human subjects

Biology: Water...more than meets the eye

This week the kids hunted for microorganisms in a sample of pond water taken from Robert and Karen Clements' pond (thanks once again for your annual donation of pond scum!).

To get a sense of what we were looking for, we started off by watching a few short video clips of different microorganisms. Then the kids prepared their slides, making sure to get a sample of pond water that was nice and goopy. After hunting around a bit, the kids turned up some interesting single-celled organisms and even a water flea. What's cool about this little guy is that being transparent means you can WATCH its heart beat!

Biology: Etrog vs Lemon

This week we studied etrogs from a biological perspective. First we classified them as citrus, a type of flowering plant and talked about the role flowers play in helping plants reproduce. Etrog trivia: What part of the flower is the pitom?

Then we asked the question: What's the difference between an etrog and a lemon? The kids started off by making some external observations: shape, color, volume, and weight, and then they opened them up and looked inside. They noted differences in the relative proportions of peel and fruit as well as differences in the volume of juice. They took the pH of each fruit and congratulated themselves on a job well-done to the tune of a tall glass of lemonade. Etrogade, we learned is pretty tough to make given how little juice each fruit contains.

Physics: Crash!

This week we continued our studies of motion through 2 mini-experiments.  The first one was an investigation of how increasing the slope of a ramp affects a car's speed. We used the same set-up from last week, (toy cars, tracks, and encyclopedias), but for the grand finale we threw in some action figures, blocks at the bottom of the ramp to simulate a CRASH, and some optional string for seat belts.  The kids observed the motion of passengers, with and without seat belts, as the cars crashed into barriers,

In the second experiment the kids were challenged to build an air-powered car using a toy car, a straw, a balloon, and some tape.  Both experiments demonstrated Newton's Laws of Motion.  More on than next week.

SCIENCE TNKERS...Go Speedracer, Go!

It's just amazing what you can learn using the Encyclopedia Britannica. In fact if you stack 4 or 5 of them, you can build a pretty cool ramp, great for exploring the concepts of motion. Get a couple toy cars and you're ready to roll! Measure the length of the track, how long it takes each car to reach the bottom, and you've got everything you need to calculate their speed.

Biology: "Newly discovered planet may have water on its surface" ....so what?

Just about a year ago a team of astronomers announced the discovery of an extrasolar planet, called Gliese 581g*. What's neat about Gliese 581g is that it may have liquid water on its surface.  When scientists search for water in space, they're looking for just one thing: life.

What makes water so special, and why do we think it's essential for life? These were some of the questions we set out to explore on day 1 of Biology. We started off by observing water's amazing ability to dissolve other substances. The kids prepared strips of filter paper, each one with a different marker color. After placing them in a bowl of water, we watched as the water traveled up the papers and dissolved the inks, revealing surprising bands of different colors.

We talked a bit about the chemical structure of water and how this structure allows water to dissolve substances easily and in doing so helps along the important chemical reactions necessary to sustain life.

*http://en.wikipedia.org/wiki/Gliese_Catalogue_of_Nearby_Stars