Book 1, Question 58
Why Do Tides Rise and Fall? The Moon's Big Pull!
Twice a day, the ocean creeps up the beach and then slides back out. The Moon's gravity pulls on Earth's oceans and makes water bulge, with one bulge on the side facing the Moon and another on the opposite side. As Earth turns, different places pass through the bulges, giving high and low tides. The page says most shores have two high tides and two low tides each day. At a beach, watch how the waterline changes over time.
From the book
Page from A Million Whys Book 1
More fun facts
- Tides are really very long waves that move through the oceans because of pulls from the Moon and the Sun.
- Tides are one of the most reliable things in nature. Like the Sun rising each morning, the ocean rises and falls along the shore again and again.
- In 1687, Isaac Newton explained that tides come from the gravity of the Sun and Moon pulling on Earth's oceans.
- The Sun is about 27 million times larger than the Moon.
- Even so, the Moon has a bigger effect on tides, because it is so much closer to Earth. Distance matters a lot for tides.
- As the tide rises, water moves toward the shore. As it falls, water moves away.
Sources: NOAA Ocean Service, NOAA Ocean Service
Questions kids ask
Who first explained the tides?
Isaac Newton explained in 1687 that tides come from the gravity of the Sun and Moon.
Why does the Moon matter more than the giant Sun?
Tidal pull depends a lot on distance, and the Moon is much, much closer to Earth.