Waves coming towards the shore.
Credit: Ron Porter @ Pixabay.com

The level of the sea rises and falls about two times each day. We call these changes tides.

The gravitational pull of the Moon creates tides on Earth . The Moon's gravity pulls the Earth's oceans towards the Moon. This causes a high tide on the side of the Earth nearest the Moon. However, on the opposite side of the Earth, furthest from the Moon we also see a high tide!

The Sun's gravitational pull also has an effect on Earth's tides. When the gravity of the Sun and Moon are pulling in the same direction, the tides are especially high. We call these 'Spring tides'. Spring tides happen at full Moon and at new Moon.

Diagram showing the effect the moon and sun has on the tides.
Creation of the tides through the position of the Sun and Moon
Credit: NSO based on Clubsail @ Wikimedia Commons

Use our tides demonstrations to explore why we have two tides each day. And find out why the timing of the tides changes with the Moon's orbit and phase.

Tides Demonstration (Age 11+)

Tides Simulator (Age 14+)

Not sure how to best use the tides demonstrations? Use our Tides Workshop to investigate the relationship between the orbits of the Earth, Sun and Moon and the tides.