Because Alex is so desperate to study chemistry, we’ve started working through Real Science Odyssey’s Chemistry Level 1. We thought it would be a lot more fun to have a friend along for the labwork, so Alex’s friend B will be joining us once a week. He gets fun science experiments, we get to enjoy his company. Win all around.
Tuesday was our first time doing a couple of labs. B was dropped off, and Alex and B were eager to get started. I got them at the kitchen table with their lab sheets, and began the reading. It quickly became obvious that both kids had some of the basic pieces of information already, but they didn’t really have a frame to put the facts into. “Chemicals are all around us; everything is made of chemicals.” “You mean elements, right?” “No, chemicals. Is water an element, or air, or plastic?” “Oh. Still, they’ve got elements in them.” “Yes, but elements are just the building blocks, and chemicals, in the form of molecules, are what makes up matter.”
I set them to looking around the kitchen for chemicals, and they seemed to be having a little conceptual difficulty. “Look! Here’s some wood!” “Here’s cloth!” I told them that these things were made up of chemicals, and that I was looking for something a little more basic, like “sugar”, or “water”, or “soap”. I asked them if there were any dangerous chemicals, and they both looked a little mystified. Surely parents wouldn’t let something dangerous be around the house?
I showed them the cleaning products under the sink, and we talked about how things like bleach and cleaning solutions can be bad for you. I showed them a regular AA-cell battery, and told them that there was acid inside the battery, and if they ever found a battery that was leaking and looked all rusty, then they shouldn’t touch it. They seemed a little thoughtful, and when they got to the “dangerous chemicals” section on their lab sheets, they both filled in “bleach”. Alex’s first answer was “the sun”, because if you look at it for too long it can hurt your eyes, but she soon decided that was a little too broad, and went with “acid”.
We studied the ingredient list on a box of cheese crackers, and both kids were surprised to see so many things added to the crackers. I told them about how chemical names are carefully designed to tell chemists information about substances — there’s a difference between sulfate and sulfite, for instance. I gave a nod to the earlier mention of elements, which seemed to make B feel a little better.
We moved on to the next lab, which was about telling substances apart with physical and chemical tests. The substances we were working with were confectioner’s sugar, baking soda, and baby powder. Alex was very proud of knowing that baby powder was actually “talc, the softest mineral”, but she didn’t seem to know what that might mean. I let them poke around in the materials, and get a little more familiar with them, and then asked them to describe what they looked like. They looked at me like I was deranged, since they were all white powders. I poured out some table sugar and asked them if that was the same, and a little light started to come on. When I asked them to rub each one between their fingers and describe what that felt like, they really started getting into it. Baby powder felt like feathers, baking soda like sand. I asked them to smell, and the baby powder smelled like flowers.
I brought out three glasses with some water in each, and we added some of each substance. The talc floated, the sugar dissolved, and the baking soda sank. I asked them to write this down on their lab sheets — B was fine about it, but Alex was on fire to keep on with trying new things. This turned out to be a theme for the whole lab; B would write things down, while Alex would want to push on. They might actually make a good pair for labwork, but I want them each to have some basic skills and understand why they are supposed to write things down at every step, instead of relying on filling it in later.
We cleaned out the glasses, and moved on to adding food coloring to see what happened. The kids enjoyed watching the water turn blue, but it wasn’t a big thrill. Then we cleaned out the glasses again, and used vinegar. Things got a little different then, as the baking soda started to fizz dramatically.
We then cleaned out the glasses again, and switched to olive oil. The results were very different from what happened with the water and the vinegar. The talc had been a dependable “float on top” option throughout, but it turned out to not float on the oil. Nothing dissolved in it, either, even if we stirred and stirred! When we added some food coloring, it was interesting to watch the layers of separation, but Alex and B were surprised to not see general mixing. We added oil, water, and food coloring, and saw what happened. The sugar dissolved in the water, and got a broadly dispersed green color, and the kids were falling all over themselves to add some vinegar.
The results were interesting — when you pour vinegar into an oil and water mixture, it only reacts when it works its way down through the oil, and we got big bubbling globs as a result. The sugar mostly dissolved, and the talc was just a gunky mess. I gave in and let the kids mix everything together, and they got a weakly fizzing greenish mixture, which seemed to excite them.
At this point, we all realized that Alex had stopped recording her results some time ago. B offered to let her use his results, but I made her write it out from memory, which didn’t go well. When we were done, I showed them how oil and water mixed into a layered result, which met with a resounding “meh”. B suggested adding soap to that mixture to see what happened, so we did, and I set it aside while we had lunch.
During lunch, we talked a little about how a chemist might approach identifying some random unidentified white powder. They seemed to get the more obvious answers, like “talc floats on water!” or “baking soda fizzes when you add vinegar!”, but the concept of starting with the physical examination seemed to not sink in too deeply. I talked a little about how safety is important when you’re dealing with things that you haven’t identified, although I took care not to blow it up too much.
After lunch, they went off to play until B’s mother came to pick him up. In retrospect, I wish I’d done a dry run of the experiment so I would have realized how much time would be spent washing glasses; had I known that, I’d have had more glasses ready, and kept the flow going. It’s easy to lose their attention if you have to break the flow of things, and when they’re coming up with odds and ends to see how they fit in, and indulging their curiosity, you need to stay on top of everything. Otherwise, I think a good time was had by all, and I look forward to Chem Lab with our friend B again sometime soon!