Product review for Large Surplus Fresnel Please read our review guidelines and see the terms of use of posting a review. Overall Rating: and share your thoughts with other customers Sort Reviews: Newest | Oldest | Highest Rating | Lowest Rating   :: Viewing page 1 of 1  -  Monday, September 24, 2007 Great Energy Demonstation Reviewed By: Matthew Caddell (San Diego, California) I use this lense to demonstrate how much power is contained in light energy. Focused down to 1/16 of a square inch, it magnifies the heat intensity by a factor of 2000. Instantly burns green leaves, etc.. Is there an energy crisis?! Not if we learn to recover the energy that's already around us.  -  Saturday, February 23, 2008 melt rock Reviewed By: Tim Ebert (Auburndale, Florida) Over twenty years ago my dad bought one of these lenses for me from Edmond Scientific. We made a solar furnace. It could melt some pumice, and burn lots of stuff. I tried using several at once to increase the power, but that task was beyond my skill at the time. The sun moves and changes the focal point. I enjoyed using the lens, but it requires more experience/help than the typical 12 year old possesses to make a real furnace.

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