We already know that cornstarch and water mix to make a non-newtonian fluid. Here’s what can happen when you stress and relax it rapidly (where rapidly is 80 Hz)
Category Archives: DIY science
E is for Equilibrium
Ice, Ice Baby
“Instant ice” from a supersaturated solution.
The Billy Preston Effect
Will it Go ‘Round in Circles?
Building The Amazing Steam Candle
This is a variant of the pop-pop engine — if you point the tubes parallel rater than in opposite directions, you’ll get linear propulsion.
At first glance you might think this couldn’t work. Once you hit steady-state, the rate at which water enters and exits the tube has to be equal. Inside the tubes, that means that the momenta must be equal in magnitude, but opposite in direction, meaning no net momentum for the water, and no propulsion for the boat. The effect is a little more subtle — one has to consider what happens at the entrance to the tube. The water exiting will have its velocity vector along the direction of the tube. But the incoming water is drawn from different directions; it only has to have a component of its velocity in the direction of the tube, meaning the ejected water exerts a greater force.
Smile! Look at the Pinhole!
Pinhole Camera Solargraphy at Astroengine.
[The] solargraphs are taken by a compact camera film cartridge (plus tiny pinhole) strapped to an inanimate object for long periods of time. However, due to the low speed of the camera film and light restriction (plus, as this is Bristol, plenty of overcast days), the six-month exposure brings a surprising amount of detail to the shot. Every day when the Sun was shining (and days when it was struggling to get through the clouds), the path it made through the sky every day was captured.
The original site is Pinhole Photography and has some very interesting pictures and information. Also check out the Solargraphy site.
Kids, Try This at Home
Make your own carbon dioxide. At 44 g/mole, it is heavier than the other major constituents of air, so it stays in the pitcher and can be “poured” out.
Physics, by The Hollies
Blame it on Eddy
“Eddies,” said Ford, “in the space-time continuum.”
“Ah,” nodded Arthur, “is he. Is he.”
This time, though, Eddies in the penny. And he enforces Lenz’s law.
You can see a similar effect if you drop a magnet down a copper pipe, because the eddy currents will flow, and the induced field is such that it opposes the acceleration, so you get braking.
If you want to be more practical, instead of moving the magnet you could move the copper around, cyclically, and tap into the current that would flow. Just a thought.
Give My Creature LIFE
Or at least make it spin a little. A simple motor: battery, magnet and wire.
Magnetic field sees a changing current and that results in a force, which gives you a motor. Quite similar to the Faraday motor, but then, he was allowed to play with mercury (and he never wore a bike helmet, either)
Update: Give MY creature life. Built one myself this afternoon, and even figured out how to upload it to YouTube. She may not look as pretty as these other motors, but she loves to spin. (First attempt didn’t go so well, but I found lighter wire that was still stiff)