Month: September 2010
Avalanche Disk
In the Science Storms section of the Chicago Museum of Science and Industry, you’ll find the mesmerizing sight of an avalanche disk. This 20ft disk spins at a variable rate and angle, and, from the video, you can see that the glass beads simulating an avalanche on the disk move very much like a fluid even though they are not. This is what’s called a granular flow and it’s driven by gravity and friction between particles.
Combustion in Microgravity
‘Hot air rises.’ It’s common knowledge. But we usually forget that this is only true thanks to Earth’s gravity. On Earth, a candle flame’s distinctive pointed shape is due to hot air rising. Without gravity, there is no buoyant convection; hot air has no reason to rise (and no definition of what up is either!). This makes flames in microgravity spherical, as in the video above from a drop tower on earth. See also: astronaut explains fire in microgravity.
Shock Waves in Space
Shock waves are not just an earthbound phenomenon. They can be found in space as well. In this photo, gas (colored yellow) ejected from a dying star hits clouds of gas and dust (colored blue), creating shock waves. #
