Magnetic Movie

Magnetic Movie from Semiconductor on Vimeo.

Fun with Gas

Fahrenheit Roller Coaster

Hershey Park's newest ride is the steepest roller coaster ever, featuring a 97-degree slope (7 degrees beyond vertical!) that results in 4 G's worth of force. Looks like a piece of cake.

Using Metamaterials to Render Objects Invisible

Theoretical physicist Michio Kaku discusses the possibility of rendering objects invisible using tiny light-bending materials in this Natural History article.

In order to make an object invisible, visible light needs to be bent around the object. Think of a stream of water flowing around the surface of a stone: water flows around the perimeter until it makes it way completely around that stone and continues along its original path. If the same feat can be done with light rays, that stone would be invisible!

Doing so requires light waves to be bent at extreme angles previously thought impossible. But scientists have synthesized new "metamaterials," that do just that. In 2006, researchers at Duke University and Imperial College London built materials that made objects invisible to microwave radiation.

These metamaterials must be smaller than the wavelengths of the radiation they are bending, so doing the same with visible light is a considerably more difficult feat: while microwaves have a wavelength of 3 centimeters, visible light waves have a wavelength of only a few hundred nanometers. (One nanometer is one billionth of a meter. That's really really small: approximately five atoms fit across one nanometer.)

Developing the nanotechnology required to make invisibility cloaks appear to be researchers' biggest challenge. So scientific teams across the world are currently exploring different methods of refracting red light, since red light has the longest wavelength in the visible spectrum. Whether or not any of these methods succeeds is anybody's guess; but, the ultimate goal is to bend all frequencies of light completely around the object, rendering it invisible. Far out.

Water Balloon + Flame Experiment

What happens when you put a balloon above a lit candle? It pops, right?

Well, what happens if you fill that same balloon with water and put it above the lit candle? The balloon pops and water spills all over the place? Nope!

Water boils at 100 degrees celsius -- a temperature too low to pop the balloon. As long as there is liquid water in the balloon, the balloon's temperature will not rise above the temperature of boiling water; therefore, the balloon will not pop.

Gotta see it to believe it? Check it out here!

There are more Robert Krampf videos here. Let me know if there are any interesting demos you'd like to see in class!

Ketchup In A Bottle Trick

Does anybody know why the ketchup packet sinks when you squeeze the water bottle and floats when you let the bottle go? Jayvon and Jose, this is another version of a Cartesian Diver -- one of which you constructed for your science fair project -- so you two should definitely know and share the answer!

Ublach, Not Oobleck

Ms. Carmody noted that the term "ublach" closely resembles the quasi-scientific term "oobleck."

Oobleck is a mixture of 1 part water to 1.5-2 parts cornstarch, and the play stuff of elementary and middle schools everywhere. It's fun to play with because it's a non-Newtonian fluid. Non-Newtonian fluids don't act like typical solids, liquids, or gases. For example, oobleck normally behaves like a liquid, but when it's stressed (e.g., squeezed between your fingers), it behaves like a solid.

A foreign TV show filled a small swimming pool full of oobleck, and filmed people running across the pool. If the participants move quickly, the oobleck acts like a solid and people can run across the pool. If they take too much time getting across, however, the oobleck acts like a liquid. What do you think happens to these unlucky participants? See for yourself who makes it across the gauntlet.

Also, check out what happens when people put oobleck on top of a powerful speaker and blow air at it. The strange patterns are a result of the sound waves moving through the fluid.

Oobleck is a particular type of non-Newtonian fluid, known as a dilatant or shear-thickening fluid (STF). These fluids have many applications. For example, scientists are trying to use dilatants or STFs to make body armor. Normally, the body armor is gel-like, but when a bullet strikes the armor, it instantly becomes bullet proof.

If you're interested in oobleck, make a batch of it yourself at home (don't worry, it's fun and easy to make...just be sure to clean up the mess). If you want to learn more about strange and fun materials, read this article in the New Scientist (disclaimer: this article is intended for advanced students). Let me know how it goes.