How to Make a Convection Currents?

Do you know why the seawater flows? Our Colorful Convection Currents science experiment will tell you why. It is a super fun stem activity for kids to do at home and at school.

Age: 3+      Time: <10mins

 Safety 

1. Be careful with the hot water.
2. Adult supervision.

 Materials List 

• Four Erlenmeyer flasks
• Cold water
• Hot water （about 60℃）
• Food coloring
• Plastic card
• Cotton gloves

 Instruction 

Step 1/6 – Add a few drops of yellow food coloring to two flasks, then fill the bottle with cold water.

Step 2/6 – Add a few drops of blue food coloring to two flasks, then fill the bottle with hot water.

Step 3/6 – Put a plastic card on the hot water bottle and slowly turn the hot water bottle upside down. (If the hot water is too hot, you need to wear a pair of cotton gloves.) Place it mouth-to-mouth right on a cold water bottle.

Step 4/6 – Slowly pull out the plastic card. You can see that the colors stay still.

Step 5/6 – Put a plastic card on the cold water bottle and slowly turn the cold water bottle upside down. Place it mouth-to-mouth right on the other hot water bottle.

Step 6/6 – Slowly pull out the plastic card. You will see two colors mix together.

 Troubleshooting 

Why when I put the bottle upside down, the water flows out?
— Make sure that the bottle is full of water. Each bottle must be filled to the rim with water.

Why my colors mix together very slow?
— Enlarge the temperature between the cold water and the hot water.

 Scientific Description 

The density of the cold water is higher than that of the hot water because the hot water molecules expand. As we know the liquid with higher density will sink to the bottom. When the hot water is placed on top of the cold water, cold water stays in the bottom bottle and the less dense warm water stays on the top. Yet, when the cold water bottle is put on top of the warm water, the cold water flows to the bottom for it is denser. That is why the color is flow in the bottle. The movement of the seawater is partly because of the different temperatures among different parts of the ocean, forming convection currents.

 Extensions 

Do you know why the plastic card can seal the water?

The difference in density is what makes this science experiment is. Check out below these easy experiments sharing the same principle that will help your little one better know the concept of density.  

Density Rainbow Column

Colorful Sugar Density Column

Suspended Egg

Homemade Lava Lamp

Firework In A Jar

Shaving Cream Rain Clouds