CLOSE

Math Professor Vs. His Own Shadow

Matthew Weathers is a math professor at Biola University, and he likes a good gag. For April Fools' Day this year, he played the prank below on his students, in which his "shadow" on a projection screen started to misbehave. All sorts of interesting stuff begins to go down, including manipulation of a computer desktop, and even removal of the desktop entirely, allowing us to "see through" the projection screen to the blackboard behind it. Ultimately the president of the university has to step in and take care of the shadow. Check it out:

For more context, this appears to be part of a discussion of Flatland, a book about interaction between different dimensions (as in this video, the 2D shadow interacts with the 3D world of the professor). You may also enjoy Weathers's Halloween prank from 2009, again related to Flatland. You can actually read Flatland online (it's in the public domain) if Weathers has sparked your interest!

(Via Waxy.org.)

Original image
iStock
arrow
science
Belly Flop Physics 101: The Science Behind the Sting
Original image
iStock

Belly flops are the least-dignified—yet most painful—way of making a serious splash at the pool. Rarely do they result in serious physical injury, but if you’re wondering why an elegant swan dive feels better for your body than falling stomach-first into the water, you can learn the laws of physics that turn your soft torso a tender pink by watching the SciShow’s video below.

Original image
iStock // lucamato
arrow
science
What's the Saltiest Water in the World?
Original image
iStock // lucamato

Saltwater is common around the world—indeed, salty oceans cover more than two-thirds of the globe. Typical saltwater found in our oceans is about 3.5% salt by weight. But in some areas, we find naturally occurring saltwater that's far saltier. The saltiest water yet discovered is more than 12 times saltier than typical seawater.

Gaet’ale is a pond in Ethiopia which currently holds the record as the most saline water body on Earth. The water in that pond is 43.3% dissolved solids by weight—most of that being salt. This kind of water is called hypersaline for its extreme salt concentration.

In the video below, Professor Martyn Poliakoff explains this natural phenomenon—why it's so salty, how the temperature of the pond affects its salinity, and even why this particular saltwater has a yellow tint. Enjoy:

For the paper Poliakoff describes, check out this abstract.

SECTIONS

More from mental floss studios