How Does The Moon Control The Tides

This is an article from Curious Kids, a serial for children. You can send your question to curiouskids@theconversation.edu.au. You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

How does the Moon, being so far away, affect the tides on Earth? – Lachie, historic period viii, Doreen, Melbourne.

Great question Lachie!

The curt answer is that the Moon'southward gravity pulls the oceans (and us) towards it. Even though the Moon is and so far away, it is big enough that its force of gravity is strong enough to exercise that.

But before we get into how the Moon affects tides, allow's expect at what tides are.

Tides are the rise and fall of water level in the oceans (and lakes, and fifty-fifty in your loving cup of water, but they're very small).

When the sea level rises to its highest betoken, we phone call that high tide. When it falls to its everyman betoken, that's called depression tide.

The ascent and fall of the tides is known as the tide cycle. If there'south i high tide and 1 low tide a day, like y'all would see if you went on holiday to Perth, it's called a diurnal tide cycle. If there are ii high tides and ii depression tides, like yous see in Victoria, it's called a semi-diurnal tide wheel.

The Moon has the most effect on the tides, but it's not the just factor that affects them. The Sun and the Earth can besides affect the tides. Nosotros'll start with the Moon.

Baca juga: Curious Kids: Are there living things on different galaxies?

Tides and the Moon

The Moon affects the tides because of gravity. You volition have noticed that every time you jump, you ever land back on the ground. This is because the Earth'southward gravity is pulling you lot back downwardly.

The Earth's spinning means that some other high tide occurs on the contrary side of the Globe to the Moon. Shutterstock

The Moon has gravity of its own, which pulls the oceans (and us) towards it. The Moon's gravitational pull on united states is much weaker than Earth's, and then we don't really discover it, but we can see the Moon's effect on the liquid water of the oceans. The oceans are pulled towards the Moon's gravity slightly, causing a bulge or high tide on the side of the World closest to the Moon.

The Earth'south upshot

If the Moon causes a high tide on one side of the Earth, what causes the loftier tide on the other side?

The Earth is spinning, which is why nosotros accept night and day. The Earth'due south spinning means that another high tide occurs on the opposite side of the Earth to the Moon.

These two high tides draw water abroad from the rest of the oceans, causing two low tides betwixt the high tides.

Why do nosotros have tides? - Forces of Nature with Brian Cox: Episode 2 - BBC One.

The Sun

The Sun, only like the Moon and the Earth, also has its own gravity which can bear on the tides. Although the Lord's day is much larger than the Moon and has more gravity, information technology's besides much farther away, meaning its pull on the tides is less than one-half as strong as the Moon's.

It withal does have an effect, though. When the Sunday and Moon are in line with the Globe (when a full moon or new moon occur), their combined gravity cause very high tides (and very low tides), known as "spring tides."

When the Lord's day and Moon are at correct angles to each other (during a waxing or waning moon), the Dominicus helps to cancel out the pull of gravity from the Moon, causing lower loftier tides and higher than average low tides, known as "neap tides".

Lunar and Solar tides diagram. Shutterstock

So the Moon affects the tides because of gravity, but gravity from the Lord's day and the spinning of the Earth also change how the tides bear.

Best wishes,

Mark Hemer.

Baca juga: Curious Kids: Is there anything hotter than the Sun?

Hello, curious kids! Have you lot got a question yous'd similar an expert to reply? Inquire an adult to transport your question to us. You lot tin:

* E-mail your question to curiouskids@theconversation.edu.au
* Tell us on Twitter by tagging @ConversationEDU with the hashtag #curiouskids, or
* Tell us on Facebook

Please tell us your name, historic period and which urban center you lot live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won't be able to answer every question but we will practise our best.