Additional links/resources:
Viscosity Chart - of various fluids
Walking on Oobleck - You-Tube movie of some folks with a pool-full of oobleck. You have to see this one!
Viscosity Chart - of various fluids
Walking on Oobleck - You-Tube movie of some folks with a pool-full of oobleck. You have to see this one!
Oobleck - A Non-newtonian, Dilatent Fluid
This is a classic science demonstration/activity used by many a teacher. As a tool to investigate states of matter, fluid dynamics, or non-newtonian and rheoscopic fluids, students love this one. Simply take some ordinary, grocery-store supplied corn starch. Add enough water to form a thick slurry and, viola!, you have Oobleck. When a stress is applied (such as squeezing or hitting) the runny liquid suddenly acts as a solid.
After mixing, students can research the different properties of Oobleck by rolling it on the counter, cutting it, hitting it, etc. If some zip-lock bags are supplied they can even take it home. If it begins to dry, just add a few drops of water.
The only precaution: prepare for a messy room or lab. Although the fluid can be kept putty-like by constant motion, counters and floors tend to show the signs of thourough scientific investigation of all properties of the stuff.
After mixing, students can research the different properties of Oobleck by rolling it on the counter, cutting it, hitting it, etc. If some zip-lock bags are supplied they can even take it home. If it begins to dry, just add a few drops of water.
The only precaution: prepare for a messy room or lab. Although the fluid can be kept putty-like by constant motion, counters and floors tend to show the signs of thourough scientific investigation of all properties of the stuff.
[click picture to view video]
Homopolar Motor - an amazingly simple device
If you have an AA battery, a couple of strong neodymium magnets, and some copper wire laying around, you can construct this simple motor in just a few minutes. The rate-limiting step is bending the wire so that it will balance on the battery and barely touch the magnets. A pair of needle-nosed plyers will help here. I crimp the wire in the middle, fold in over in a heart or apple shape, and bend the bottom tangentially to the magnets. With a little manipulation, you have a homopolar motor. (see video for more on its construction)
This is a great demonstration or activity to help illustrate the concepts of current, motors, conduction, or Lorentz forces. (It's also a great project you can do while the students are testing!)
This is a great demonstration or activity to help illustrate the concepts of current, motors, conduction, or Lorentz forces. (It's also a great project you can do while the students are testing!)
Additional links/resources:
Homopolar Motor - wikipedia
You-tube video of a homopolar motor
Another Design from Sci-Toys
Homopolar Motor - wikipedia
You-tube video of a homopolar motor
Another Design from Sci-Toys
[click picture to view video]