Wednesday, March 25, 2009

More Fun with Lasers

Laser pointers are fun. I have found several uses of them in the classroom. I was just goofing off with one this afternoon and showing my literature class (I have some of the same students for science too) the Tyndall Effect. I got an Erlenmeyer flask and stopper. I lit a few matches and dropped them into the flask and topped the flask with the rubber stopper.
The smoke from the matches is a colloid. Smoke is made up of small particles that are suspended in the air of the jar. When shining the laser into the flask, the laser light passes through the glass into the smokey atmosphere of the flask and out the other side. While in the flask, the smoke particles reflect the laser light, making it visible. Nifty!

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