This week · Experiment 01Which falls first?
A book and a sheet of paper. Every child knows the answer — until they try it.
Resist giving an answer.
Hold the book in one hand and a flat sheet of paper in the other, at the same height. Ask: “If I let go of both, which one lands first?”
Ask for a guess — and, more importantly, a reason. Most children (and most adults) say “the book, because it's heavier.” Write their reason down. You'll need it.
Drop them. The book wins — the reason seems right. Now lay the flat sheet on top of the book and ask again before you drop them together. The paper stays with the book all the way down. Then crumple the paper into a tight ball and race it against the book.
Read their reason back to them: “If heavier things fall faster, why did the paper keep up?” Don't explain. Let them try ideas — fold it, flatten it, fan it, drop it again.
When they get there, they'll have found it themselves: it was never about weight. Something invisible was holding the flat paper back.
Air. The flat sheet has to push a lot of air out of the way, so it drifts. On top of the book, the book clears the air for it; crumpled into a ball, it barely meets any. Without air, everything falls at the same speed, whatever it weighs.
In 1971, astronaut David Scott dropped a hammer and a feather on the Moon, where there is no air. They landed at the same moment, just as Galileo had argued centuries earlier.
