Comments | big_bad_al: Will It Lens? Table of Contents

big_bad_al

Will It Lens? Table of Contents

Apr 09, 2009 12:54

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lens, will it lens

Comments 123

anonymous April 10 2009, 19:17:50 UTC

Peeps!

Peeps. Peeps. Peeps.

PEEEEEEEEEPS!

dieplz April 10 2009, 19:28:20 UTC

YES.

big_bad_al April 10 2009, 23:52:36 UTC

It's already on our list of stuff to try. Great minds think alike!

Flames anonymous April 10 2009, 19:32:11 UTC

Try Strawberry Pop-Tarts.

Re: Flames big_bad_al April 10 2009, 23:53:16 UTC

Interesting! I'll add it to the list.

Testing solar sails anonymous April 10 2009, 19:34:56 UTC

Just taking a toy car with a sail made with a reflective material could do the trick.

http://en.wikipedia.org/wiki/Solar_sail

Re: Testing solar sails big_bad_al April 11 2009, 01:41:47 UTC

Let's do a rough calculation of how much force we could get from using the lens as a solar sail. We can get about a kilowatt of sunlight focused through the lens. The relativistic momentum of a photon is its energy divided by the speed of light. However, if we reflect the photons instead of just absorbing them, the change in their momentum is twice their absolute momentum. So the force we could get from using the lens as a solar sail is

1 kilowatt / c * 2 = 0.000007 newtons

That's way too small to do anything because it is dwarfed by the force needed to overcome air friction (let alone the friction in the wheels of the car). Solar sails don't become a plausible mode of transportation until you're in the vacuum of space (no friction) with thousands of square meters of sail (reflects more light) and years to wait (you accelerate very slowly because the forces are so small).

(The comment has been removed)

big_bad_al April 11 2009, 00:32:11 UTC

The seashell was a mussel we saved from dinner one night. It started out all black, and we burned off the color (we suspect the white part is mostly leftover calcium).

I think the lens was about $120, but once you include the materials for the frame and stand, stronger filters for the welding goggles, the skillet, etc., we've probably spent $200.

chouyu_31 April 12 2009, 02:50:02 UTC

We are in Santa Monica.

Speakers anonymous April 10 2009, 20:04:33 UTC

In high school my friends and I used one of these (for an overhead projector) to burn the following items:

Mini-donuts (covered with wd-40)(it lit on fire)
A modem
Someone's car stereo speaker

That last one got us all suspended.