Secrets of the tides At any coast, the tide flows up and down, in and out. But WHY?
HOW TIDES WORK
1. The Moon is smaller than the Earth, but it still has gravity. It pulls on the Earth’s water, making it ‘bulge’ towards the Moon.
Tides happen because of the Moon – but it’s complicated!
Prepare for some brain-boggling space science…
H igh tide Moon
H igh tide
Earth Pull of gravity
3. The Earth spins once a day, so different parts of the sea move into the bulge areas. They rise up, making a high tide!
Low tide
The Moon’s gravity causes tides.
2. The Moon also pulls the Earth, making it swing around slightly as the Moon orbits it. This makes water bulge out on the side opposite the Moon too!
TIMES OF THE TIDES
But wait… it gets even weirder! The tide goes in and out roughly twice a day – but not exactly…
New moon
The Earth spins, moving through two high tides a day. 8 whizzpopbang.com
F irst quarter
But at the same time, the Moon orbits the Earth, about once every 28 days.
Full moon
This means the bulges change position, gradually moving around the world.
Third quarter
So it actually takes a bit more than 24 hours for the tide to go in and out twice. Each day, high tide happens a bit later than the day before.
