Paper boats

After some attempts to make floating canoes with paper and glue, which inevitably sunk when the glue dissolved, friend of the lab Arthi provided us with an origami paper boat. We sailed (and sank) our boat in the bathroom sink, much to the delight of jr scientists A and E. The experiment also turned into a surface tension experiment when our paperclip passenger stayed afloat after our boat sank. Remembering back to an old experiment, we added some dish soap and watched the paperclip plummet.

Stalagmites and stalactites, take 3

Never willing to admit defeat, we've made another try at making stalagmites and stalactites. We noticed that the area around our crystal experiments was covered with crystals. It seems that the salt water evaporated in the hot sun, but was too heavy to stay in the air and condensed out. We decided to take advantage of this to try to grow stalactites. We put a mesh (a cut-out from a screen door) on top of the jar for our latest experiment, hoping it would catch the escaping evaporated salt water. We poured our crystal making materials into the jar while it was covered by the screen so some of the liquid would stay on the screen and start a layer of crystals for the rest to hang on to. We weren't able to grow stalactites with this technique, but we got an unexpected but happy result. The evaporated salt water seemed to get trapped inside the jar so we ended up with one big thick crystal that covered the bottom of the jar. Pretty cool. I want to try this in a disposable cup next time so we can easily get the crystal out to play with. It looks like we'll finally have crystals that aren't to delicate to handle.

Frozen boat

Inspired by an episode of MythBusters, we made a boat out of wet scraps of paper frozen together. We sandwiched the wet paper between two tupperware containers and put it all in the freezer. After it was frozen, we popped out the boat and set it to sail on the high seas of the bathroom sink with some brave gingerbread men, much to Jr. scientist A's delight. After a few minutes, the boat thawed and came apart. We put it back between the tupperware containers to re-freeze and sail again another day.

Moon-gazing

Jr. scientist A is really into outer space right now, and he got a telescope for the holidays. We weren't quite sure if he'd be able to look through the lens or understand what he was looking at. After a few times of me setting up the telescope and having him look at the moon, he decided he wanted to see some more earth-bound objects through the telescope. We started playing a game. I would aim at something familiar from across the apartment complex (like a decoration in his bedroom window) and ask him to tell me what he saw. He was generally able to identify what I pointed the telescope at - guess he was able to see through the telescope.

Going out to look at the moon (and some local objects) through the telescope has since become a nightly ritual. The only problem is that when there are a number of adults around, it's hard for Jr. scientist A to get a turn!

High flying fun

I swear there was a time when I could make paper airplanes that flew, but that time has clearly passed. So I got a book on making paper airplanes (recommended by friend of the lab Arthi). We were able to make a bunch of really cool airplanes (some of which actually took decent flights). Although I got this book for Jr. scientist A, I was surprised at how much fun the younger Jr scientist E had watching the airplanes fly by. She eventually started toddling over to where they fell and bringing them back for another flight. We had a lot of fun seeing how different designs and different modifications resulted in different flight patterns (I have to confess that I started making two of each design because I wanted more turns!). At some point, Jr. scientist A must have decided that the planes were flying because they were made of paper and insisted on trying to fly an (unmodified) paper bag. This isn't the first time that he's gone from observer/participant to actively guiding experiments in new directions, and I have to say I'm a bit proud of that!

Ice melting experiment

We had previously used salt to briefly drop the melting point of ice. This time we tried it on a larger scale. We made two ice cubes. The first one (red in the video) was made using water that had Epsom salt dissolved in it. The second one (green in the video) was made using plain water. This wasn't exactly the cleanest experiment - the plain water cube ended up noticeably bigger and was frozen for a shorter period since we already had salt ice cubes sitting around - part of a long-term experiment I'll write about when it's finished. But I expected the effect to be large enough that the general results would be unaffected. As shown in the video, the salt ice cube did melt much faster (about half an hour compared to 1.5 hours for the albeit larger plain water ice cube). You can see from the pool around the edge of the plate how much quicker the salt ice cube was melting. The two ice cubes also melted in very different ways. The plain water cube primarily just got smaller. It still had the typical smooth edges of an ice cube. The salt ice cube started looking very rough and "eaten away" even though it started out smooth. The one oddity was that the plain water ice cube started melting much quicker. We may need to do a more controlled experiment. Although Jr. scientist A enjoyed watching the ice cubes melt, I was surprised that he showed little interest in the sped up video, which I thought would be easier for him to grasp.

Good clean fun

Today we did an experiment that Jr. scientist A named the messy messy experiment. We made some bubble mix (water + dish detergent)and headed outside to play with bubbles. We used a funnel to make different sized bubbles (depending which end we blew into) and tried out a new bubble maker -two straws connected with string- with mixed results. The experiment ended with playing around in puddles of bubble mix and lots of fun.

Hand-crank flashlight

After getting a hand-crank flashlight at the store, we decided to try to build our own mini version. We used a small electric motor and a couple LEDs. When we manually spun the motor (using it like a little power generator), the LED lit up, much to jr. scientist A's delight. Even cooler, when we had the two LED lights connected with opposite polarity (switching where the positive lead went), one would light up when we spun the motor in one direction and the other would light up when we spun the motor in the opposite direction. Very cool experiment.

Paper helicopter

We did a science experiment I found in the book "The Usborne Book of Science Fun." We made an easy-to-build paper helicopter (takes less than 5 minutes to make). We also made a more durable version out of art foam. Because of the way the wings stick out, the helicopter spins around as it makes its way to the ground - just let it go from a height and it does the rest. We even tried dropping it over a third floor balcony for an extra long spinning flight. A fun little experiment.

Diving pen cap

We made a pen cap that dives on command. We took a pen cap, attached a string loop around it and added four paper clips to the loop as weights. We then filled a big soda bottle with water until it was almost completely full. We dropped the pen cap into the bottle and screwed the top on tight. When we squeezed the middle of the bottle, the pen cap sank because the air bubble inside it was compressed. When we let go, the air bubble expanded again and the cap floated back to the top. It took a little practice to get the weighting and water level right. When the cap capsized, causing the air bubble to escape and the cap to sink to the bottom, we used a magnet to drag the paper clips and cap to the top so we could reach in and pull it out without emptying the bottle.

Scaredy-cat toothpicks

More fun with surface tension (one of Jr scientist A's new favorite phrases). We did an experiment showing that floating toothpicks will run in terror from soap. We arranged the toothpicks in a bowl of water so that they formed a complete enclosure - this helps them keep their relative position. You need to make sure that every toothpick, including the last one, is above another toothpick on one end and below another toothpick on the other. Then we covered the end of a new toothpick in dish detergent and gently put the soapy end into the water in the middle of the other toothpicks. Instantly the floating toothpicks moved away from the center, scattering to the edges of the bowl. A fun experiment that has a big "wow" effect, is easy to re-set up (just wash the toothpicks and bowl and refill with new water), and with a little guidance, can be a hands-on experiment for a little tyke. Now Jr. scientist A keeps asking me to do that experiment again!

Rain shadows

Even though it wasn't raining, we decided to make rain shadows. We used a spray bottle full of water as the rain. We put different objects on the dry cement and sprayed all around their edges. When we removed the objects we had a "shadow" of the object that had been there. We even made a rain shadow of Jr. scientist A. A fun experiment.

Turning salt into glue

We tried to pick up ice cubes with string, using salt as the "glue." The idea is that, when you put salt on ice with the string resting on the ice, the salt lowers the ice's melting point, causing it to start to melt a little. As it refreezes, the ice freezes around the string. Our first attempt was a dud. You could feel that the string stick a little to the ice, but pulled right off. But it turned into an accidental experiment on states of matter - jr. scientist A was delighted to find that when he held the ice in his hand, it turned into water. For our second attempt, we realized that we needed to first wet the string. That turned out to be the key. With our salt and wet string, we were able to lift up the ice - although the effect was somewhat short-lived.

Mixing colors

Jr. scientist A got a science kit for his birthday that included pipettes and tablets to make colored water, so we started mixing colors together. It took some practice for him to get used to using the pipettes, but once he got it working, he was intrigued that mixing two liquids together created something that didn't look like either of the things he started with.

Baking soda and vinegar balloon

Having previously mixed baking soda and vinegar together to make a bubbly mess, we decided to try to harness that released carbon dioxide to inflate a balloon. We poured baking soda into a bottle, added vinegar, and then quickly put a balloon over the opening of the bottle. Very quickly the balloon started to inflate, much to Jr. scientist A's delight. A fun and repeatable experiment - just a little hard to get the balloon on in time.