Sorting by more than one property
Chemistry · Early Years · The School
One test at a time
You have sorted things before. Floats or sinks. Hard or soft. Sticks to a magnet or not. Each time, you used just ONE test. That is a good start, but it only tells you one thing about an object.
Combining two tests
Now try TWO tests together. Does it float? Is it also squashy? Some things float AND are squashy, like a sponge. Some things float but are NOT squashy, like a wooden block. Combining two questions narrows your sorting down much further.
Why combining helps
Imagine you need something that floats AND is hard, for a boat toy. "Floats" alone gives you too many things to choose from. Adding "hard" narrows it right down to just the objects that fit both. Two tests together find exactly what you need.
A sponge, a wooden block, a metal spoon, a cork, a stone and a plastic duck. Test each one for FLOATS and for HARD. Sponge: floats, soft. Wooden block: floats, hard. Cork: floats, soft. Plastic duck: floats, hard. Metal spoon: sinks, hard. Stone: sinks, hard. Four groups appear: floats-and-hard, floats-and-soft, sinks-and-hard, and nothing at all in sinks-and-soft today. Two simple tests, and the six objects sort themselves into a clear pattern.