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.

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.

Make-shift bubble blower

I promised jr. scientist A that we would make bubbles, but I couldn't find any of our bubble blowers. We decided to try to make some with objects we had around the house. One of the best bubble makers was an empty toilet paper roll. We dipped it in some bubble mix and then blew into the other end. If we blew slowly we got really big bubbles (although they often popped while still attached). It was a lot of fun, and when the toilet paper roll got soggy, we just let it sit for a couple hours and it was ready to be used again.

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!

Floating paperclips

Our previous attempt to use surface tension to float objects found that a paperclip was too heavy. Looking around online, it seems like there might have been a flaw in our approach. By dropping the paperclip in, we might have broken the surface tension. This time, we first floated a piece of paper and dropped a dry paperclip on the paper. Then, using a pipe-cleaner, we pushed the paper under water, being careful to not touch the paperclip. The paperclip stayed floating on top of the water. I then gave Jr. scientist A a couple paperclips to drop in the water and he watched in amazement as his paperclips just dropped to the bottom while mine floated (thanks to the paper trick I used with mine). True to the physics of floating-by-surface-tension, we added a squirt of dish detergent to the water and the floating paperclip sunk like a stone... er... like a paperclip.

Making things sink on command

Today we played with surface tension. We dropped a loop of yarn onto a bowl of water and it floated. We then added some drops of dish detergent, breaking the surface tension, and the yarn sank to the bottom. We repeated the experiment with a few other objects. A twisty-tie floated until we added the detergent. A paperclip sank right away - oops too heavy. Paper floated, even after we added detergent, but sank to the bottom when we pushed it under water. A cork floated no matter what we did. Its buoyancy amused jr. scientist A.