Lately Captain Jelly Belly has been obsessed with a show called Fetch! With Ruff Ruffman, which airs on PBS. It’s kind of a game show in which six kids are given different tasks to perform in each episode, to earn points, and then at the end of the season (22 episodes or so), the one with the most points wins a trophy. The tasks are so, so cool though — stuff like learning to windsurf, becoming a Formula-1 crew chief, giving the weather report on the local news, or surviving in the woods for two days with nothing but a knife and a sheet of plastic.

A lot of the time the kids have to do something science-y, like make a to-scale model of the solar system (a whole city big!), or design a water balloon launcher. From watching Fetch!, the Captain has developed a real interest in science experiments, and is always asking if we can try them at home. For a while there, we spent every evening before bed doing float tests. We’d get a big glass of water and then we’d go through everything in the fridge and pantry, putting a little bit into the cup to see what would float, and what would sink.

Mustard sinks and looks really cool. Mayonnaise sinks too, and looks like little plops of poop, which is a really big hit with the five-year-old crowd. Salad dressing is cool because it separates and the oil part floats, while the vinegar and spices sink. Cheerios float. Sugar will use a slick of oil floating on the surface as a little boat, but if you stir it up, the sugar will sink while the oil floats back to the surface.

Milk just mixes with the water and obscures everything else, so don’t bother to try it.

Anyway, every night we’d end up with this totally disgusting cocktail of goo, which was kind of fascinating and repulsive at the same time. It’s really a good thing Gal Smiley was usually in bed by the time “experiment hour” rolled around, because I think the Captain was very, very interested in getting someone to try to drink it.

After a while I got kind of tired of testing the same old stuff and having the same conversation over and over about how mayonnaise looks like poo, so I introduced a new experiment idea: weighing stuff to see which was heavier.

I asked the Captain how we could do such a thing, and I almost cried with pride when he said, “We will have to build a balancing machine.” Do I have the brainiest kid ever, or what? I can hardly wait until he has to bring me to prom.

So we talked it over and together we came up with a basic design for the Balancing Machine, then we got Sir Monkeypants to build it because tools were involved.

Here it is:

What we have here is two large tupperware containers with a piece of wire from a coat hanger spanning the distance between them. The wire goes through the exact centre of a popsicle stick (from a BLUE popsicle, obviously), so the stick can pivot freely. The stick has two notches, equidistant from the ends, from which hang two identical baggies. We can place items in the baggies and see which one is heavier.

Here we are confirming that two identical Dora The Explorer finger puppets weigh exactly the same:

Here we are demonstrating that a single Dora finger puppet is heavier than a plastic pterodactyl:

The Balancing Machine reminds me of everything that is good and fun and cool about being a parent. It’s working on a project together with your kids, and seeing their minds open to new things, seeing them excited to think and excited to discover and excited to learn.

It’s good times, right there, good times.