Falling: Everything Drops the Same

Lesson 7 of 10 · 7 min · Free, no account needed

What you will learn

Without air, everything falls the same way, heavy or light. Air is what slows a feather.
Falling with nothing but gravity is free fall. On Earth the speed grows by about 9.8 m/s every second.
That acceleration is called g. Other worlds have other g: the Moon about 1.6 m/s², Jupiter about 24.8 m/s².

A bowling ball and a feather, dropped together in a tube with no air. Which lands first?
Drop them with air, then pump the air out and drop again.
Slow motion. Compare the landing times.
Drop a ball from a tall tower. One flash every second.
Press Step and watch the speed column.
Falling with nothing but gravity has a name.
Free fall: moving under gravity alone. In a vacuum, a feather and a bowling ball fall together.
g ≈ 9.8 m/s²: on Earth every falling thing gains about 9.8 m/s each second.
Simplified model: we leave out the air. In real air, light and wide things fall slower.
You land somewhere new. A ball dropped from 2 m takes about 1.6 s to land. Set g to match.
Slide g, press Drop, read the clock. Then Check.
Game: planet guesser. Five drops, one minute.
Watch each 2 m drop and its clock, then tap the planet. Get 4 right.
Code: games drop things with two lines in a loop. Put the program in order.
The ball starts 20 m up. Each turn of the loop is 0.1 s.
A ball is dropped from a tower. Where is it after 1, 2 and 3 s?
Drag each flash. Use the speed table from before: 0, 9.8, 19.6, 29.4 m/s.
Which world did you land on in step 5?
Tap it to see every planet's g.

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