Cool tides

Here are some very cool gifs of high tide vs. low tide all around the world - what a change in water level! These alternating pictures were probably taken at a very certain time of the month though, when tides have the most extreme differences: during a new moon.

If this were a picture of the new moon, it would just be a black square

You might already know that the moon affects the tides, but maybe not exactly how. Also, these pictures were taken during the day - why would the moon matter then? Because the moon's gravity is always affecting water on earth; in terms of time, it's easier to think about the earth rotating underneath the moon rather than the moon revolving around the earth, because earth's rotation around itself takes 1 day and the moon's revolution takes 28.

The strongest tides are when the moon is "new" (invisible) because that's when the moon is on the same side of the earth as the sun. No light can bounce off its surface and hit us - the angle is impossible, so the moon is invisible, but its gravity is now being added to the sun's to pull on Earth's water. Check it out:

There's some fun extra stuff in this video too

The water bulges out on both sides because it can't take water all the way from the other side, it only lowers the water level at the "sides," leaving extra water on the other end. The water is also being pushed outward slightly because of the centrifugal force, like if you took a wet basketball and spun it, flecks of water would go everywhere.

Or a cat

For more information on the moon, check out my post about eclipses