Biology: Playing with Proteins

This week we took the first few minutes to analyze the results from our investigations into organic compounds. It's a credit to your kids' ability to record data carefully, that they were able to analyze the results 2 weeks later in order to figure out which foods contain protein, starch, simple sugars, and fats.

The main focus of science this week was to observe reactions between the enzyme catalase and hydrogen peroxide. After discovering that the catalase in potatoes causes hydrogen peroxide to break down into water and oxygen, the kids designed experiments to test other substances for the presence of of this enzyme. The kids chose a wide range of substances to test including chocolate, avocado, lemon, grass, and Pringles. Sadly, unlike with regular potatoes, hydrogen peroxide had little to no effect on the Pringles.

Biology: Testing for Organic Compounds

This week we discussed organic compounds. First we dispelled any myths about organic compounds being any healthier than regular old compounds. Likewise, if someone tries to charge you more money for an organic compound, don't fall for it! In chemistry, organic means relating to living things and containing lots of carbon atoms.

We used chemical and physical tests to know whether the 6 foods in question contained proteins, fats, or carbohydrates (starches or sugars.) With all the test-tubes, droppers, and indicators flying around, we didn't get to draw our full conclusions. Stay tuned next week for a full report.

Physics: Circuits are cool!

Today's experiment was originally called: "Experimenting with different kinds of circuits," but about 5 minutes into it, the kids decided to change the name to "Circuits are cool." We did, and they are. The kids learned about the parts of a circuit: battery, load, and wires, and they were challenged to build circuits that could turn on light, 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. Afterward the kids recorded their results in their lab-books using circuit diagrams.

Biology: Modeling carbon compounds

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 butane molecule.

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

Physics: Charge your batteries!

This week we investigated batteries: how they work, how to measure their voltage, and what happens when you put them in series.

My original plan was to have them build circuits, but wouldn't you know it...all my AAs were dead. Pretty embarrassing the first week and all... Luckily I had just gone grocery shopping and had plenty of lemons, potatoes, salt, and vinegar.

Why was this lucky? No, I did not distract them with lemonade and french fries ... it turns out that with a few strips of copper and zinc, wires, and various produce, you can light an LED.

Look out McGyver, here we come!

Physics: Whatever floats your boat

This week the kids were given 6 items to analyze. First I asked them to order them by weight. The twist was they had to do it first by guessing, and then by measuring the weights with a scale. The kids were pretty surprised by how wrong their guesses were. We wondered why it was that some things, like say, a large piece of styrofoam "feel" lighter than others when they actually weigh more. We got some clues when we moved on to part two of the lab: testing each item to see if it floats or sinks in water. Wouldn't you know it, the things the kids thought were light, were floaters, and the things they thought were heavy, were sinkers. However, contrary to our expectations, whether something sinks is NOT simply about weight.

Then each kid was given a lump of clay. After observing that it too was a sinker, they were challenged to build a boat out of said sinking clay, and not just that, but a boat that could carry cargo (any number of marbles, also sinkers). After some trial and error, the kids figured out which shapes worked best.

Then, just for fun, the kids made bouncy balls out of water balloons.

General Science: What's a yeast's favorite food?

This week we learned a little bit about our tiny unicellular fungal friend, the yeast. After all, we have a lot in common: We eat, reproduce, respire...we're practically identical. So when it came to investigating which foods yeast like best, we decided to use something else we have in common: When we're done eating (and transforming the energy from food into energy our cells can use), we all release carbon dioxide. This comes in handy when we use yeast to help us make bread. It is the carbon dioxide gas that causes the bread to rise.

We compared carbon dioxide production in yeast when fed 5 different kinds of food: salt, flour, sugar, ground-up cookies, and ground up vaflim (wafers). To get an idea of which food was eaten most heartily by our yeast, we covered each bottle with a balloon. Then we sat back and watched the show. The samples of yeast fed sugar, cookies, and vaflim were the happiest, i.e. the balloons were the most inflated because of the greater production of carbon dioxide. The flour came in second place. We discussed how cookies contain sugar, and how flour, a complex sugar, can be broken down into simpler sugars. A little more work, but when you're hungry, you do what you have to. Yet one more thing we and yeast have in common...LAZINESS! Who here isn't counting down the days 'till summer vacation?!