Fold it to the Moon
Take a sheet of paper — about 0.1 mm thick, thinner than your fingernail. The Moon sits 384,400 km away. No rockets involved here: just your hands and a very large imagination.
0.1 mm per sheet10 folds ~ 10 cm42 folds ~ 440,000 km
The question: How many times must you fold the sheet so that its thickness reaches the Moon?
the result
42 folds
Every fold doubles the thickness. Doubling feels slow at first: after 10 folds you're still at only ~10 cm, desk height. Keep going.
Work it out
- Thickness after n folds: 0.1 mm × 2ⁿ.
- Target: 0.1 mm × 2ⁿ ≥ 384,400 km = 3.844 × 10¹¹ mm.
- So 2ⁿ ≥ 3.844 × 10¹², which means n ≥ 41.8.
- Check: 2⁴² × 0.1 mm ≈ 440,000 km — past the Moon.
- At 41 folds you're at ~220,000 km — over halfway, but short.
42 folds. With your bare hands paper stops folding after 6–7 tries; the world record — a kilometre-long sheet and a steamroller — is 13.
What it teaches
Exponential growth. Doubling is the fastest-growing pattern there is, and it always feels impossible right up until it passes the Moon.