Back when BP was still trying the "top kill" method of slowing the flow of oil into the Gulf of Mexico, the news was full of references to "drilling mud."
This stuff is no ordinary mud. It helps a rig drill faster and keeps the equipment cool and lubricated, but it's got some wacky other properties. It's a non-Newtonian fluid. That means its viscosity changes as you apply stress. If you punch or hit a shear thickening non-Newtonian fluid, the atoms in the fluid rearrange themselves in such a way that the liquid acts like a solid. A shear thinning non-Newtonian fluid (like ketchup or toothpaste) behaves the opposite way, getting thinner and drippier under stress.
Still don't quite get it? Check this video:
When they're running--applying a stress whenever their feet strike the surface--the fluid acts like a solid and they can walk on top of it. But when he stands still....
The Mythbusters have played with this phenomenon, too:
So. Drilling mud behaves kind of the same way. Here's Bill Nye explaining it all on CNN. When the drilling mud passes through a narrow opening, under pressure, it locks up and acts more like a solid. The idea was that if BP could pump a water-based drilling mud into the ruined well head and get it to solidify, then they could slow the flow of oil enough that engineers could encase the whole thing in cement. It didn't work. That's because the oil and gas spewing out of the pipe are under tremendous pressure. BP engineers just couldn't pump enough mud in there to stop the oil.
But oobleck isn't. What's oobleck? It's a non-Newtonian fluid you can make and play with at home.
Instructables tells you how.
Courtesy TheBusyBrainOn this date in 1884, Dr. John Harvey Kellogg applied for a patent for "flaked cereal". Kellogg was a health-food fanatic, and was trying to improve the diet of patients at his hospital. His search for a digestible bread-substitute led him to boiling wheat and by accident letting it stand too long and become somewhat hardened. Despite the mistake, Kellogg put the concoction through a rolling process that turned each grain of wheat into a flake, which he then baked into a crispy and light breakfast product. Kellogg's brother Will helped improve the process, began marketing it to the general public, and the rest is cereal history.
Not to freak y'all out, but did you know that germs are on everything you touch? Using a special powder called Glo Germ (get it here) you can actually see how germs spread from one thing to another. It will make you want to wash your hands more often. (And the CDC recommends washing your hands frequently. In fact, why don't you go wash up right now?)
Goal: to observe how germs are spread
Age level:: 3 and above
Activity time: 2 - 5 minutes
Prep time: 5 minutes
Encourage others to pick up and play with the objects. Ask them what they know about germs.
After the discussion, tell them that, as part of an experiment, you've put "pretend" germs on one or some of the objects they may have touched today. Switch on the UV lamp: what glows?
Reinforce the fat that the Glo Germ powder is just to simulate germs. It won't make you sick. You can get rid of the germs by washing your hands. In fact, encourage your audience to wash their hands and then hold them under the UV light again.
(On the other hand, remember that not all germs are bad. Exposure to some germs is thought to protect people against asthma and allergies or colitis, and overuse of antibacterial products leads to antibiotic resistance and superbugs as well as potential damage to the environment.)
For most of us, the first thing we think of when we hear the word "vacuum" is the common household appliance. However, that is not the only kind of "vacuum" that exists. To help expand "vacuums" beyond the common household definition, we, the Mentor Buzz team, have created a series of multimedia presentations on the word or theme of vacuums. As defined by the ever-venerable Wikipedia, a vacuum "is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure." A simpler definition of "vacuum" that we created is that a vacuum is a space that basically doesn't have air or has very little air in relation to how big the space or container is. Based on this definition, we split up into three groups and created three different projects that will hopefully explain some aspect of the science of vacuums: a video, a series of step-by-step experiments, and a game. Here is what we have created.
Were you a fan of the Mentos and Diet Coke fountains that EepyBird created? If so, you might tune in to "Samurai Girl" tonight (7pm, ABC) to see EepyBird's experiments with more than 250,000 sticky notes. You can also check out an extended version of the video, complete with how-tos, at EepyBird.com.
Here's a sneak peek, but definitely check the EepyBird site tonight for more.
Courtesy George Karamanis
“Keep your options open.” Sounds like good advice, right? Turns out, it has hidden costs.
Professors Dan Ariely and Jiwoong Shin at MIT ran an experiment to test rational behavior. Test subjects played a computer game. On the screen were three doors. If they clicked on a door, it opened. Click on it a second time, and a number would appear, and they would earn that much money. Click on a different door and it opens, but the first door closes. Some doors had higher average payoffs than others. The object of the game is to get as much money as you can in 100 total clicks. (You can play the game—without the money, sorry—here.)
Obviously, the winning strategy is to find the door that pays the best, and then keep clicking on it. But then the evil professors threw a curve. They presented a second version of the game, where the doors shrank and eventually disappeared if you didn’t click on them. Subjects would waste clicks keeping the lower-paying doors from disappearing. On average, they earned 15% less for the privilege of keeping their options open.
Ariely and Shin hypothesize that players kept the less-valuable doors open, even though it cost them money, to avoid the pain of losing the door forever. We all hate to lose things. But sometimes the cost of keeping them around is more than they are worth. The game is a good lesson in the value of just letting things go.
It's all over the Internet. It's on David Letterman and the Today Show. It's on NPR, for Pete's sake. Across the country, people are caught up in a frenzy of extreme Diet Coke and Mentos experiments.
Get permission, go outside, and have a hose handy. Things are gonna get messy...
Of course, you don't have to use Mentos and Diet Coke. The good folks at EepyBird.com have done many, many experiments, and it turns out that dropping just about anything into any kind of soda creates at least a little fizz. But Mentos and Diet Coke is an especially satisfying combination.
So how does it work?
The explosive effect is caused when the carbon dioxide that's been compressed in the soda escapes so quickly that the pressure pushes the soda out of the bottle. That's the easy part. But why do Mentos, in particular, cause such a good effect?
Part of the answer has to do with nucleation sites. "Huh?" you ask. Yeah, me, too. Soda is a liquid supersaturated with carbon dioxide gas, and nucleation sites are places where the carbon dioxide can make bubbles. A nucleation site can be a scratch on a surface, a speck of dust, or any place where you have a high surface area relative to volume.
And Mentos have a lot of nucleation sites. There are lots of imperfections in their surfaces, and that allows lots and lots of bubbles to form. Plus, Mentos are heavy enough to sink when you drop them in, so they react to with the soda all the way to the bottom of the container. The sticky result is a fun, foaming mess.
But what happens if you drink Diet Coke and eat Mentos at the same time?
The EepyBird website has the answer, if you really must know...