A Crookes Radiometer makes a handsome curio to boggle the brains of anyone who comes near! Place the radiometer in sunlight and the vanes begin to spin on their own!Science can literally be at your fingertips when you own a Crookes radiometer! These curious objects have been around for over 100 years, but they can still impress even the most jaded minds in our modern world of technological wonders!What is a Crookes Radiometer and How Does it Work?The Crookes Radiometer was invented in 1873, not surprisingly by a man named Crookes! A radiometer (also known as a light mill or solar radiometer) looks like an old fashioned upside down light bulb with a tiny weather vane inside of it. When it is exposed to light, the vanes begin to spin on their own as if by magic!Of course it's not really magic! In the early days apparently there was some debate as to how the thing actually worked, but nowadays it's believed that the effect is caused by solar radiation (aka heat and/or light). Basically the dark side of the vane absorbs more heat energy than the lighter side (something you will know if you've ever worn a black shirt on a hot day!) and this causes a net exchange of heat which acts like a miniature heat engine or a tiny weather system. Place the radiometer in sunlight and the vanes spin: it's cool even if you don't know exactly how it works!Two sizes are available: 18cm and 22cm. Order a Crookes radiometer today for a distinctive Father's Day or Christmas gift for any scientifically curious person on your list!
