Science fair projects with water

What to expect

Water is the easiest thing in the house to experiment with, and it's free. It melts, freezes, soaks into paper, climbs up a strip of paper towel, dries up in the sun and holds up a foil boat, and every one of those can be measured: minutes for the ice, centimetres for the climb, pennies for the boat. That's what makes these real projects rather than demonstrations. Each one changes one thing (the salt, the shape, the temperature, the place) and measures what the water does, three times at every level.

Water projects are messy in a good way, so do them on a tray or by the sink and keep a towel close: a wet floor is slippery. Where a project needs hot water, a grown-up pours it, and no project for 1st grade uses hot water at all. Most of these take one sitting, but the ones outside, like the rain gauge and the puddle that dries, depend on the weather, so check the forecast before you pick one. On fair day, bring photos of the cups instead of the water itself, because some fairs say no liquids on the display table.

Counted from the projects on this page: 3 about how things move, 25 about water, ice and mixing, 12 about growing and weather; 30 using kitchen things, 10 using the outdoors and some seeds. 29 are free with what most houses have, and the rest cost about $2 or about $1 or about $3. Testing takes from 1 to 14 days. 9 have a step a grown-up does, marked on the page.