3. Ocean tides
What causes ocean tides? What does the position of the sun, moon and Earth have to do with it?
A tide is the rise and fall of the ocean. Tides are caused by the gravitational attraction between the sun, Earth, and moon. The Earth pulls on the moon and the moon pulls on the Earth and causes the ocean to bulge on the side that faces the moon and the very opposite side. Those bulges cause a high tide. The parts that aren't bulging, are going in and they are called low tides.
The blue parts represent the high tide and the parts on the side where you see no blue represents a low tide. There are constantly high tides and low tides all over the world. Some higher than other times and some lower than other times. This would be because of the moon. If there's a full moon then there will be very high and low tides, but if there's only a half moon, the tides won't be as high.
Spring and neap tides
Spring tides are especially high tides and they only occur during a full moon and a new moon.
Neap tides are especially low tides and only happen during quarter moons.
As you can see, tides are very important and they can determine wether or not it's safe to swim.