How do tides work?

Tides are the rise and fall of sea levels caused mainly by the gravitational pull of the Moon1 and, to a lesser extent, the Sun.

Most coastlines experience two high tides and two low tides each day.

Why are some tides bigger than others?

Spring tides — the largest — happen when the Sun and Moon align, adding their gravitational pull together.

Neap tides are the smallest and occur when the Sun and Moon are at right angles.