Hot and Cold Water Density Ocean Currents! Experiment

Watch this portion of my video below to check out this fun science experiment!


  • two empty plastic bottles
  • food coloring
  • hot and cold water
  • laminated card
  • an adult science helper

Directions: Fill up one of the bottles with cold water and dye it blue. You can also use any color you want. Fill up the other bottle with hot water and dye it yellow. You can also use any color you want. Make sure you have an adult help you with the warm water! Now, place the laminated card over the mouth of the hot water bottle. Then, flip it over and balance it on top of the other bottle as shown here! Then, carefully pull the card out of the middle. Watch as the two liquids don’t mix! It only mixes in the center. Take a look at where the two liquids meet. What do you notice?

This experiment was originally published as a YouTube Short last year. Find the original here.