Daily Bulletin


The Conversation

  • Written by Mark Hemer, Senior Research Scientist, Oceans and Atmosphere, CSIRO

Curious Kids is a series for children. If you have a question you’d like an expert to answer, send it 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.

Why are there waves? - Evie, age 5.

Thanks for a great question, Evie.

When you look at the waves breaking at the beach, those waves might be at the end of a long journey. The waves might have been created thousands of kilometres away, or they could have been created near you.

There are lots of types of waves in the ocean, but the waves you usually see at a beach are created by the wind. When the wind blows over a smooth ocean, it creates little waves or ripples on the surface. If the wind continues to blow, the waves grow bigger.

Curious Kids: why are there waves? A big wave lands at Dee Why Beach in Sydney. Taro Taylor/Flickr, CC BY

Read more: Curious Kids: How does the Moon, being so far away, affect the tides on Earth?

Faster, bigger, longer

The faster the wind blows (like in a strong storm out at sea), the bigger the waves will grow.

The further the wind blows (or the bigger the area of the storm), the bigger the waves will grow.

And the longer the wind blows (like in a storm that lasts a long time), the bigger the waves will grow.

If the wind stops, or changes direction, the waves will stop growing, but they won’t stop travelling.

They will keep travelling away from where they were created in a straight line, sometimes for days, until they run into something like a beach where they are stopped because they break. That’s why there are still waves at the beach, even when it is not windy.

Waves trip over themselves

Imagine you were running really quickly. But then suddenly, you ran into thick gloopy mud. Your feet would slow down, but the top half of your body would still be going fast. You’d trip over.

Waves do the same thing and that is when they break.

As waves approach the shore, the water is shallower, and the bottom of the wave starts to feel the sand and rocks and seaweed. The bottom of the wave slows down, and soon, the top of the wave is going faster than the bottom part of the wave, so the top spills forward and topples over in a big splash.

Curious Kids: why are there waves? This wave is breaking over the top of the surfer because the top half of the wave is travelling faster than the bottom half. Flickr/Duncan Rawlinson - Duncan.co - @thelastminute, CC BY

Waves can travel a long way

Scientists who study the ocean (called oceanographers) have measured waves created in the Southern Ocean, and seen them travel all the way across the Pacific Ocean and break on the beaches of North America more than a week later.

Try counting the seconds between waves breaking on the beach. If the time between waves is 10 seconds or more, the waves have come from a long way away. If the waves were created nearby, the time between waves will be short, perhaps five seconds or fewer.

Sometimes when we look at the sea we might see different waves (some big, some small) all happening at the same time. These waves were created at different places, perhaps by different storms, but ended up in the same spot at the same time.

Freak waves

During big storms, waves can get very big. If big waves from two different storms meet together, that can create enormous waves that we call “freak waves”. The largest waves measured are around 25 metres high (that’s five giraffes standing on top of each other!) and they can tip over ships.

Read more: Curious Kids: How do plastic bags harm our environment and sea life?

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au

Curious Kids: why are there waves? CC BY-ND Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.

Authors: Mark Hemer, Senior Research Scientist, Oceans and Atmosphere, CSIRO

Read more http://theconversation.com/curious-kids-why-are-there-waves-112015

Writers Wanted

Of all the places that have seen off a second coronavirus wave, only Vietnam and Hong Kong have done as well as Victorians

arrow_forward

Mould and damp health costs are about 3 times those of sugary drinks. We need a healthy housing agenda

arrow_forward

How To Spot On A Good Online Gaming Website

arrow_forward

The Conversation
INTERWEBS DIGITAL AGENCY

Politics

Prime Minister Interview with Kieran Gilbert, Sky News

KIERAN GILBERT: Kieran Gilbert here with you and the Prime Minister joins me. Prime Minister, thanks so much for your time.  PRIME MINISTER: G'day Kieran.  GILBERT: An assumption a vaccine is ...

Daily Bulletin - avatar Daily Bulletin

Did BLM Really Change the US Police Work?

The Black Lives Matter (BLM) movement has proven that the power of the state rests in the hands of the people it governs. Following the death of 46-year-old black American George Floyd in a case of ...

a Guest Writer - avatar a Guest Writer

Scott Morrison: the right man at the right time

Australia is not at war with another nation or ideology in August 2020 but the nation is in conflict. There are serious threats from China and there are many challenges flowing from the pandemic tha...

Greg Rogers - avatar Greg Rogers

Business News

Guide to Shipping Container Hire

If you are thinking of hiring a shipping container rather than purchasing one, there are many great reasons to do so. It is a more affordable option and when you are done using it for what you neede...

News Co - avatar News Co

Top 5 US Logistics Companies

Nothing is more annoying than having to deal with unreliable shipping companies for your fragile and important packages. Other than providing the best customer service, a logistics company also ne...

News Co - avatar News Co

Luke Lazarus Helps Turns Startups into Global Stalwarts

There are many positive aspects to globalization. It is no secret that those who have been impacted by globalization tend to enjoy a higher standard of living in general. One factor that has led to ...

Emma Davidson - avatar Emma Davidson



News Co Media Group

Content & Technology Connecting Global Audiences

More Information - Less Opinion