Sorry, this one evokes nothing but boredom for me.

Even after an explanation, it is dull.

But if a star is so far out there it is possible that we can’t see the light. With that said, is a house hold flashlight intense enough to be seen from the moon?

With that said, does ANY light from that flashlight reach the moon, even on a clear night?

Something here seems anti-intuitive for me that doesn’t seem to meet Dan’s three-act theory.

See for example : http://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment

http://scottfarrar.com/ma2011/speed%20of%20light%20demana.PNG

I felt they were asking things backwards too. We didn’t know the speed of light when we were asking “How far is the Sun?” And we’re just given the Moon’s distance? How droll.

What kind of prompt lets our students ask,
1. “How far is the moon?”
2. “How big is the Earth?”
3. “How far is the sun?”
4. “How big is the sun/moon?”

#2 is in Michael Serra’s Discovering Geometry. But the “real” solution to it involves travelling to the equator :)

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David: the first one isn’t quite instantaneous. Its just much faster.

I think you’re right that the speed of light is a tough concept, but what I find more difficult is to fully grasp the vast distances in astronomy.

Ask anyone to try to draw the Earth and Moon to scale, along with their to-scale distance. How many will come remotely close?

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Ok, I have a new question. “How long is the second beam of light?” 7 light seconds?

Actually in just looking this up… that means the 2nd dot is not the moon. What the heck is 13 light seconds away from Earth? Whole lot of nothin!

And the first dot? Too close for the moon. ISS?

Explaining that light has a speed, and that despite our common sense judgement that it travels instantaneously fast, it actually travels much slower, is quite a difficult thing to do. The problem really is that at the scales we are used to dealing with on an everyday basis, light IS essentially instantaneous.

I think, in order for your video to work, students will have to understand a fair bit about light & distances between the sun and the moon to be able to even see the question that is being asked. I would imagine that your video poses an interesting question for students in an upper high school level or 1st year university physics course, which is not a bad target market.

I wonder if a game could be written which actually took the speed of light & relativistic effects into account, and allowed students to play around with the idea of a maximum speed of light at more human comprehensible scales, would help people understand these concepts more deeply than the ability to manipulate the formulas and get “the answer.”