This mechanical marvel built in Austria sometime between 1715 and 1725 is handy alarm clock. When the alarm is activiated, the clock rings a bell and triggers a flintlock mechanism. That latter part doesn't fire a gun, but instead lights a candle. This would be handy if you're getting up at some indecent hour--a highly overrated practice.
Link -via Wunderkammer | Photo: British Museum
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On a TV, if you illuminate one pixel then illuminate the one next to it, it appears as though the image is moving. If you do the same thing but skip to every second or third pixel, the image appears to be moving faster. Every tenth pixel, the image shoots across the screen. Nothing is actually changing speed; we just see the gap increase.
If you had a laser beam strong enough to be visible after reflecting off the moon, and you moved the beam from one part of the moon to the other, it would take about 2.5 seconds for you to see the beam move on the moon's surface.
That's the amount of time for the beam to reach the moon, and return.
When the person moves the laser, the photons that are currently arriving at the moon do not move.
The photons exiting the laser take over a second to get to the moon, and arrive at the second location.
Take a hose and spray something far from you. Then flick your wrist and aim to another spot on the driveway. It takes a second for the water exiting the hose to catch up to the new target. Same idea.
This guy isn't that smart.