Electromagnets

After previous unsuccessful attempts to make an electromagnet (and my clear deficiency in electrical experiments), we turned to my first science teacher, Dr. A, for a little help. After finding the right type of wire (who knew there's a lightly insulated wire labeled specifically for making electromagnets - well I didn't, but thankfully Dr. A did!), we quickly had our electromagnet up and running, complete with a light switch that turned the magnet on and off. Jr. Scientist A had fun flipping the switch on, picking up metal objects like paperclips and silverware, and then flipping the switch off and watching them drop. Some paperclips did get temporarily magnetized, making the dropping effect a little less dramatic and the concept a little less clear, but it was still quite a success.

Floating bubbles

This has to be one of the coolest experiments we've done. Since Jr. Scientist E loves bubbles, I've been trying to find some more bubbly experiments to do with her (although she never gets tired of watching baking sod and vinegar fizz, I sure do). I ran across a cool one where you create carbon dioxide by mixing baking soda and vinegar and then you use bubble mix and blow some bubbles into the container. Since carbon dioxide is heavier than the air inside the bubble mix bubbles, the bubbles go into the container and then come to a rest in mid-air (resting on top of the invisible carbon dioxide). The bubbles will pop if they hit the edge of the container, so you need to do this in a large container with a lot of baking soda and vinegar (ah Costco, the kitchen scientist's best friend). The effect is absolutely jaw dropping and both Jr. scientists A and E loved it.

Playing with brains

Jr. scientist A was playing with a brain puzzle we have (yes, we have a brain puzzle). I picked up a piece and said "here's the cerebellum." Jr. scientist A picked up a different part of the cerebellum and said to me, "no, this is the cerebellum, it looks like a tree." I have no idea how he knew that!

Engineer in training

What a difference a week makes. When we first got the circuit kit a week ago I was a little concerned that it would be too difficult for Jr scientist A to do much on his own (after all, it was marketed for kids twice his age). But after a few days of playing with it, not only is he able to manipulate all the pieces, but he's started making working circuits all on his own (he made the one in the picture without any help - note that he only put down the pieces necessary for the circuit). He's even starting to learn to use the diagrams in the manual to make circuits. He's still having trouble identifying short circuits, but it's been amazing to see how quickly he's picked up everything.

Playing (safely) with electricity

We got Jr. scientist A a snap circuit kit where we can put together different electrical experiments (the different parts of the circuits snap onto a board like Legos). He had lots of fun trying to put every piece of the kit on the board but I was eventually able to convince him to separate out the pieces needed for the "flying saucer" experiment (the little island of circuits in the middle of the board). After a little fiddling we launched the flying saucer by putting it on the motor, getting it going fast, and then cutting the power. The little disk flew up in the sky - it was pretty cool. Bedtime got pushed back quite a bit as we played with the new toy.

Hypothesis testing

Jr. scientist A came up with a hypothesis and we decided to test it. He had discovered that the pump for his stomp rocket had a little nozzle that could be removed. He hypothesized that the nozzle, with its smaller opening, would result in less air being pushed out of the pump and thus the rocket would fly a shorter distance (personally I thought the smaller nozzle would result in greater pressure and thus a longer distance flight). We tested the hypothesis by setting up the stomp rocket and firing off rockets either with or without the nozzle in place. We marked each place the rocket landed - blue for with the nozzle and white for without. To my surprise, all three white lines (no nozzle) were farther than all three blue lines (with nozzle). This was a moderately well received introduction to rigorous hypothesis testing, but clearly a tad bit advanced for Jr. scientist A.

Baking soda and vinegar reaction without the vinegar

We found this reaction by accident. We decided to try to make baking soda crystals. Just like we've done when making salt crystals, we started with dangerously hot water so that we could dissolve a lot of baking soda into the water. To our surprise, when we dropped the first spoonful of baking soda into the water, it fizzed up as if there was vinegar in the solution. Thinking that I had grabbed a container that had a little vinegar residue in it, we marched on with our crystal experiment (standing a little farther back). Every time we added baking soda, we got another fizzy reaction, long past the point where any vinegar residue would have been used up in the reaction. It turns out that mixing baking soda into hot water does create carbon dioxide, just like when mixing vinegar and baking soda. Granted this was (unintentionally) not the safest experiment, but it's always fun to find a new fizzy reaction. Of course, Jr. scientist A had quite a lot of fun repeating this one.