5 Layers of the Ocean: Ocean Zones Activity

Have you ever swam to the bottom of the deep end of a pool? That’s generally 12 feet deep, which is about the height of two Tom Bradys! Your ears start to pop, and you can feel the weight of the water above you. If you were in the ocean, you’d be in the very top layer, the Sunlight Zone. Below that, there are still four more zones — the deepest being 36,070 feet below the surface. That’s 5,636 Tom Bradys!

Let’s dive in, starting with the deepest layer first since that’s how we’ll be creating our mini ocean in a jar.

5. The Trench Zone

The deepest zone of the ocean reaches into narrow cracks in the ocean floor...it’s pitch black and near freezing. It’s helpful to think of a trench as a narrow crack in the ocean floor, similar to a cave on the Earth’s surface. You won’t find any creatures with lungs or bones, like sharks or whales. But there is life. Gelatinous creatures (mostly related to star fish and jelly fish) can stand the crushing pressure.

4. The Abyss Zone

As you might guess from the name, the ocean is pretty unforgiving in this layer. It’s still completely dark and frigid, and contains most of the ocean floor (except for where it dips down into trenches). What lives here? You’ll mostly find invertebrates (that means no bones) like giant squid, but also some sharks, like the deep-diving cookie-cutter shark. While there’s no light at this depth, some creatures make their own. That’s called bioluminescence, and it makes animals glow in the dark.

3. The Midnight Zone

Yep, it’s still super dark and cold here — but you’ll find an extraordinary amount of diverse creatures swimming around. Many of them have very creative adaptations to help them survive, like bioluminescent chin growths that literally look like glowing fishing lures! Sperm whales are also known to dive into this layer down to 10,000 feet in search of their favorite meal — giant squid. Yum!

2. The Twilight Zone

Finally, some sunlight starts to shine through in this layer. It’s still mostly dark, but it’s possible to see and it’s a bit warmer. Humans can’t swim here, but recent studies suggest that this layer might contain more life than all the rest of the ocean layers combined.

1. The Sunlight Zone

When we swim in the ocean, this is where we stay — right at the surface. This is the smallest slice of the sea, and the warmest. All the fish we eat come from this layer, like tuna, mackerel and swordfish. You’ll also find sea turtles, seals, jellyfish and sharks. Because this layer gets sunlight, plants can grow here, which means plenty of seaweed and algae. To put things in perspective, though, this layer is still very deep, extending to 660 feet.

Now put your knowledge into practice to make your own ocean layer jar.

What You'll Need:

• Light corn syrup
• 5 large paper cups
• Blue and green food coloring
• 32-ounce or larger glass jar with lid, approx. 6.5” tall
• Dish soap
• Water
• Vegetable oil
• Rubbing alcohol (or mineral oil)

What You'll Do:

1. Kids: Pour 1 cup corn syrup into 1 paper cup. Add as much blue and green food coloring as you need to turn the syrup completely black. This is the Trench Zone. Pour into jar. Corn syrup is the most dense of all the liquids you’ll use — that’s why it’s on the bottom, with the next layers settling on top of it.
2. Kids: Pour ½ cup dish soap into a second paper cup. This is the Abyss Zone. Carefully pour into jar, on top of corn syrup layer.
3. Kids: Pour ¾ cup water into a third paper cup. Add only blue food coloring until you achieve a very dark color. This is the Midnight Zone. Carefully pour into jar, on top of dish soap layer.
4. Kids: Pour ¾ cup vegetable oil into a fourth paper cup. Add fewer drops of blue and green food coloring to make a slightly lighter color. This is the Twilight Zone. Carefully pour into jar on top of water layer.
5. Kids: Pour 2 tablespoons rubbing alcohol or mineral oil into the fifth clean paper cup. Add a couple of drops blue food coloring to make a very light blue color. This is the Sunlight Zone. Carefully pour into jar. Both rubbing alcohol and mineral oil will “float” on top of the other liquids — their density is the lowest of all the liquids in the jar.
6. Kids: Tightly screw on lid, being careful not to shake jar.

Different liquids have different densities, which means some liquids are heavier than others. That’s why we started with corn syrup in the bottom of the jar. It’s the most dense, or heaviest, of all the liquids we used.

If you like, you can play around with your layered ocean jar to learn a bit more about liquid density. Here are some ideas:

• Drop different objects into the jar and see where they settle — does a penny sink to the very bottom or float in a different layer?
• What about a small plastic toy shark or other animal?
• What if you push a rubber band to the bottom? Does it stay put or float up to a different layer?
• Shake the jar — do the liquids stay mixed or do they settle out again?