Homemade laser microscope reveals water's murky secrets
By Paul Ridden
August 26, 2010
Some burning questions have just got to be answered, no matter the substantial costs involved. One such question demanding attention is: can a laser pointer be used to examine the microscopic contents of a drop of water? Happily, the answer is yes, and without the aforementioned prohibitive expense. In this home experiment, a laser pointer was shone through a drop of water collected from the base of a potted plant and the magnified image projected on an opposing wall. Read on to see a video showing a bemused-looking cat watching the resulting light show.
The DIY experiment featured here was spawned after a mosquito's enlarged image could be seen in the distant view dot of a laser pointer's beam. Much forum discussion followed, which eventually led to a member placing a 250mW green laser pointer on top of a book and shining its light through a drop of water collected from the bowl of a six year-old spider plant, and then filming the resulting light show on the opposite wall. The drop of water was pushed out of a syringe to the point just before the surface tension gave way to falling water.
The drop of water acts as a small spherical lens and as the light beam passes through, refraction causes a magnified image to appear on the wall beyond. The shadows of microbial life dotting around the wall can clearly be seen dancing, feeding and apparently battling it out in the spooky green pool of light. Similar setups using pond water liquid lenses have yielded monstrous images of such microscopic organisms as mosquito larvae, water fleas and paramecium.
Okay, so it's not exactly cutting-edge nano-science, but it does makes compelling viewing nonetheless.