Tides, Waves & Currents
Know that tides are regular rises and falls in sea level caused mainly by the Moon's gravity, with the Sun contributing. Many coasts have roughly two high tides per day, while some have one. Wind makes most familiar surface waves. Currents move water and carry heat and nutrients; tides and wind can both drive currents.
What a learner can do afterwards
- Describe tides as the regular rise and fall of sea level, caused mainly by the Moon's gravity with a contribution from the Sun
- Explain that wind blowing across the water makes most familiar surface waves
- Describe ocean currents as large flows of water that carry heat and nutrients around the globe
1 · Read
The ocean never sits still. Water moves in three big ways: tides, waves, and currents. They can overlap, and one can help cause another. Tides are the slow rise and fall of the sea. The Moon's gravity pulls the water while Earth turns, and the Sun pulls a little too. Many coasts get about two high tides a day, and some get only one.
At the beach, Priya feels a strong wind blowing across the water. She watches waves roll in and crash on the sand. The wind is pushing the water into waves.
Ocean currents are like giant rivers flowing inside the ocean. Some carry warm water toward colder places, and some carry cold water toward warmer ones. They also carry nutrients, dissolved food for ocean plants and tiny animals. Wind drives many currents, and rising and falling tides drive others.
A current carries heat from warm seas toward cold ones.
Remember it this way: tides move up and down, wind pushes up most surface waves, and currents flow like rivers across the ocean.
Tides rise and fall mainly from the Moon's pull, wind makes most surface waves, and currents move water, heat and nutrients around the world.
The rewritten readings were written for this dataset.
2 · Watch
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Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.