Why Do Tides Change? Explaining Tides to 9-Year-Olds

Tides are the regular rise and fall of the ocean's water levels. They change mainly because of the moon and the sun. Here's how it works:

1. The Moon’s Gravity: The moon pulls on the Earth's water with its gravity. This pull causes the water to bulge out on the side of the Earth near the moon, creating a high tide.
2. Opposite Side Bulge: On the opposite side of Earth, there is another bulge because the Earth is pulled slightly toward the moon, away from the water, causing another high tide.
3. Low Tides: Between these bulges, the water level is lower, and this is called low tide.
4. Sun’s Role: The sun also pulls on the Earth’s water, but less strongly than the moon. When the sun, moon, and Earth line up, the tides are higher (spring tides). When the sun and moon are at right angles, tides are lower (neap tides).

Because the Earth spins, different places experience high and low tides about twice a day. So, tides change because the moon and sun’s gravity pull on Earth’s oceans as the Earth turns.