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Course: Middle school Earth and space science - NGSS > Unit 3
Lesson 3: Global winds and currentsGlobal winds and currents
Review your understanding of global winds and currents in this free article aligned to NGSS standards.
Key points:
- A current is the steady flow of a fluid (such as air or water) within a larger body of that fluid.
- Prevailing winds are air currents that blow mainly in one direction. The global pattern of prevailing winds is caused by the uneven heating of Earth’s surface.
- As prevailing winds blow across the ocean, they create surface currents in the water. Both prevailing winds and surface currents appear to curve due to Earth’s rotation. This is known as the Coriolis effect.
- Surface currents connect to form large, rotating systems called gyres. Gyres circulate heat around Earth by moving warm water from the equator to the poles.
- The ocean also contains deep currents that are driven by differences in density. Denser water, which is colder and saltier, sinks into the ocean. Less dense water, which is warmer and less salty, rises.
- These vertical currents are connected by horizontal currents at the surface and in the deep ocean. Together, this system of currents is called the overturning circulation.
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When did scientists start studying currents?(51 votes)
Ocean currents were found in the mid 1700s. Then during 1872 - 1875 one of the first books were written(48 votes)
- Does denser water move quicker than less dense water?(29 votes)
It depends on how dense the water is.(7 votes)
When was the Coriolis effect discovered?(13 votes)
The coriolis effect was didcovered in 1835 by Gustave-Gaspard de Coriolis(31 votes)
I have one question. how does the water like sink and rise?. im rlly confused rn 🤣. pls helpp(10 votes)- (saying what I know)
It is partially affected by water density. Water density is affected by temperature.
When the water temp is high, the molecules in the water have a lot of energy, (heat is one form of energy)the molecules can move more freely using the energy from the heat thus the molecules are more spread out, making the water less dense.
likewise, when the water temp is cold, the molecules don't have a lot of energy to move around with. making cold water denser. kinda like when you're sleepy. when something is less dense, it is lighter than something denser (warm water is less dense than cold water) which is why warm water rises and cold water sinks.
How salinity affects water density, I don't think I will be able to say here, for it is a little too complicated to explain in detail,
but the basic idea is that when salt (NaCl) dissolves in water, the water molecules will split the salt apart (NaCl to Na+ and Cl-) and hold the two ions apart in a cage of water molecules. depending on how much salt is dissolved, the water naturally becomes denser holding the weight of the salt(NaCl).note that dissolving and density depend on the solvent and solute
(solute is what you're dissolving, and solvent is what you're dissolving into)
hopefully this helps, Evan the chemist(19 votes)
what of a warm and saltier water does it rise or fall(9 votes)
Warm water is less likely to have salt, it also depends on the density, and will most likely rise.(3 votes)
how does this help us in our day-to-day lives?(11 votes)- it do not help us at all in life(0 votes)
why are we learning this(4 votes)
to predict weather patterns and see if its going to rain tomorrow.(10 votes)
Do Coriolis effect move clockwise or counterclockwise?(3 votes)
Clockwise in the northern hemisphere, and counterclockwise in the southern hemisphere(4 votes)
- About how many ocean currents are in the world.(4 votes)
I know this is kind of unrelated, but why dose ice float in my water, since cold fluids need to sink, and objects for the most part sink as well?(2 votes)
Objects sink if they are denser than the fluid they are floating in, and float if they are less dense. Because the hydrogen molecules in water arrange themselves so that they are more spread out when they freeze, ice is less dense than water and therefore it floats.(4 votes)
