Turn the Tides

A blue and beige round table has a flat earth picture on top with a red handle, which has a child's hand moving it.
A young girl is standing next to a yellow and blue table and exhibition panel. She is winding a red handle on the surface of the table which in turn is attached to a flat blue, white and green earth picture.

Tides are mostly caused by the Moon and solid earth also responds to tidal movements.

How it works

Spin the Earth picture to move the Moon in orbit around Earth and observe what happens to images of each tide.

Things to try or ask around the exhibit

  • Is there only one tide, or do matching tides occur on Earth?
  • Roughly how many low tides and high tides occur every 24 hours?

Background

Tides are mostly caused by the Moon as it orbits the Earth, although the Sun also influences tides on Earth to a small degree.

Tides are easiest to see as the rising and falling water levels along a beach. At high tide, water moves further up the shore and the ground rises about 10 centimetres. About six hours later in the same area, low tide occurs and the water level and ground level drops.

Matching high and low tides occur on either side of the Earth at the same time. The high tide that's on the side of Earth closest to the Moon is taller, but a smaller, matching high tide also occurs on the opposite side of the Earth.

Finding the science in your world

Many people who live along stretches of coastal areas rely on tidal calendars to time low and high tides with launching boats, navigation and crossing low lying ground. Tides also impact on aquatic and intertidal wildlife and how they breed.