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  • Space
  • Class 7–10
  • 10 min
  • Medium

Impact Crater Lab: How Big a Hole Does a Rock Make?

Connect kinetic energy (½mv²) to crater size: speed counts twice, but crater width grows only with about the 0.3 power of energy, so giant craters need enormous energy.

Before you try

What if you doubled the speed of the rock? Would the crater double too?

Try it out

Interactive activity

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What happened?

Move a control to see what changes and why.

A simple crater in solid rock using a standard energy-scaling law; the atmosphere is ignored, so small rocks that would burn up still reach the ground here.

Try these ideas

  • Keep the rock the same and double the speed. Read the energy and the crater width.
  • Swap iron for ice at the same size. Why does the crater shrink?
  • Find the smallest rock that makes a crater wider than a football pitch.

Why it works

When a rock from space hits the ground it does not just make a dent its own size. Its kinetic energy, half its mass times its speed squared, is released in a fraction of a second and blasts the ground outward in every direction. Meteor Crater in Arizona is 1.2 km across but was made by an iron rock only about 50 m wide, travelling at around 12 km/s.

Crater size scales with energy to roughly the 0.3 power, so doubling the energy makes the crater only about 23% wider. This lab lets you set the rock’s diameter, speed and material, drop it, and compare the crater with familiar things. Presets recreate Meteor Crater and the Chicxulub impact that ended the dinosaurs.

Check your understanding

Question 1 of 4

Doubling the impact speed multiplies the energy by

Doubling the energy makes the crater

Meteor Crater is 1.2 km wide. The rock that made it was about

At the same size and speed, which rock makes the biggest crater?

Explain it in your own words

What changed? Why did it happen? Where might you notice this in everyday life?

What will you discover next?

Try Meteor or Meteorite? Will the Rock Reach the Ground? next.

Continue learning

For parents & teachers

  • Drop a marble into flour from different heights and measure the crater each time.
  • Ask: why do we see so few craters on Earth compared with the Moon?
  • Work out ½mv² for a 1 kg rock at 20 km/s.

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