Earth is the only planet in the solar system that has liquid water on its surface. Most of that water lies in oceans that constantly move with surface and deep-sea currents.
In 1769 Benjamin Franklin was one of the first people to chart ocean currents by mapping the Gulf Stream in the Atlantic Ocean. Since then scientists have created detailed maps of water movement all over the world.
Water pressure, temperature, and salinity (saltiness) cause the various movements of ocean currents. The Gulf Stream is a surface current more than 50 miles wide that moves at about four miles per hour.
Deep-sea currents at the bottom of the ocean move only a few feet each day. It can take 1,000 years for deep-sea water to make its way to the surface.
SPRINGS OF THE SEA
In the Bible, God talks about the “springs of the sea” when He is speaking to Job (Job 38:16). This could be referring to ocean currents. It could also be talking about upwelling, which is when storms or currents mix deep water with surface water.
Most people, though, believe these “springs of the sea” are hydrothermal vents. These cracks in the ocean floor shoot streams of hot water and minerals into the ocean.
The vents were first discovered in 1972, yet their existence is recorded in the Bible thousands of years earlier. It’s just one of the many cases in which science has demonstrated the reliability of God’s Word.
In 1872 researchers on the British ship Challenger set off on a three-year voyage to learn about the ocean. They sailed 69,000 miles, measuring ocean temperatures and currents and taking samples of seawater and various sea creatures.
While the ship was in the Pacific Ocean near the island of Guam, scientists sent a sound signal to the bottom of the ocean. The signal told them that the spot was 35,640 feet deep.
In 1960 an undersea research craft called the Trieste dove to the bottom of the sea not far from where the Challenger had taken its reading almost 100 years earlier.
The Trieste touched bottom at 35,800 feet.
Ocean currents form when the water separates into different layers and moves at different speeds. You can create layers of water similar to those found in the ocean with simple things from your kitchen.
You will need:
Two clear drinking glasses
A stirring spoon
A measuring spoon
First, fill one of the glasses one third full of cold water. Add one tablespoon of salt and stir it until the water looks clear. Then add a drop or two of food coloring.
Fill the other glass one third full of hot water from the tap. Add a pinch of salt and stir it in.
Carefully pour the hot water into the glass of cold water. Tilt the cold-water glass slightly and pour the hot water down the side of the glass to keep the layers from mixing.
The warm water stays on top because it is less dense than the cold water. The same thing happens in the ocean.
Try creating a rainbow using four colors of food coloring. You should see four distinct layers.
• Bottom layer: cold, very salty water;
• Second layer: cold, slightly salty water;
• Third layer: hot, very salty water;
• Fourth layer: hot, slightly salty water.
You can experiment with different amounts of salt and different temperatures of water. How easy is it to make the layers mix?
Illustrated by Corbis