Summary
Mark builds a machine to skip rocks perfectly and uses it to uncover the science of the ideal skip — the right speed, spin, and angle. The robot lets him test one variable at a time.
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Ages 7+
Made for a general YouTube audience — an occasional mild or bleeped word can slip in, so preview if your classroom bar is strict.
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Teaching resources
Discussion questions
Talk about it
A skipping rock needs the right angle, spin, and speed. A robot repeats the throw exactly, so Mark can change just one thing and see what it does.
- Why is a robot better than a person for testing the 'perfect' skip?
- What is the ideal angle for a rock to hit the water, according to the video?
- If you changed two things at once, why would it be hard to know what caused the result?
Quick work-a-long
Vocabulary: variable, fair test, angle, spin.
Try it: Skip a flat stone (or slide a coin across a table) at a low angle vs. steep angle. Keep everything else the same. Which skips better?