How long does this science lesson take?

This lesson takes approximately 16 minutes to complete. It includes 29 interactive questions with immediate feedback.

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The Wait — How does radar work, and how does it find a plane nobody can see?

Radar finds an aircraft by sending out a radio pulse and timing how long the echo takes to come back: the longer the wait, the farther away it is. You learn it by doing it, with your own thumb. This is the true story of the death ray that failed - the young assistant who was ordered to build one in 1935, proved on paper that it could not exist, and wrote one line underneath that nobody had asked for: the waves cannot kill, but they can SEE.

16 min29 frågorÅrskurs 4, 5, 6

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