GIF Frenzy

Today I'm going to explain some awesome science gifs from an article on Buzzfeed:

Egg Underwater:

A cracked egg will keep its shape underwater because of the cohesion in the bubble and pressure from the water. "Cohesion" just means that it sticks to itself - like the word adhere, which means to stick to something else, but with the 'co' prefix which means together, so it literally means "sticks together." The pressure of the water helps keep the whole egg together by pushing on all sides of the egg - anything underwater feels a similar pressure.

Turning of the Cheetah:

Notice the cheetah's tail while it turns - it's using that the rotational inertia of its tail to balance the abrupt change in direction of the front of its body, much like the cat we studied in one of my first blog posts about why cats always land on their feet.

Slinky!!:

(full video here)

This is an odd one! The bottom of the spring doesn't fall until the top part has hit it - this will really happen with any dropped slinky. The video linked above explains it best, but basically the bottom of the spring is experiencing an upward force from the top of the spring, and that upward force doesn't go away until the top has met the bottom. With normal objects, the whole thing drops at once, but springs' elasticity changes things :)


The Sun Never Sets Sometimes:
 

On the top and bottom of our world, the sun is a stranger beast. Some months, the sun never rises at all, but during the summer it never sets! Because of the 23.5 degree tilt of our earth, the sun never leaves the sky near the top of the world - but in the winter, it's the opposite, and the arctic can go months without seeing the sun at all. Depressing! If you're still interested, there's a detailed explanation here

The Pythagorean Theorem:

I'm sneaking some math in on you here: this is a representation of the Pythagorean theorem,
(a² + b² = c²). Because those are squares attached to those lines, the water inside represents the square of that line's value: the 2 squares of the smaller sides add up to the square of the hypotenuse!

And finally, one of my favorite demonstrations:

Floating on air:
 

 Sulphur hexaflouride is a gas at room temperature - but gasses actually act like liquids most of the time, we just don't think of them that way because they usually mix and float about. But this particular substance is different because it is much denser than air itself, so just like when a denser object sinks in water, this "air" is sinking in the room's air, and staying contained inside the tank. 

When the cup scoops some of it up and pours it into the "ship," it increases the density of the inside of the aluminum foil and the ship sinks, just like it would if you filled an aluminum boat with water in a water tank.
Source here - with some extras that I didn't explain :)