Start by preparing your watermelon to become a volcano. You can use any size of watermelon you like, just adjust the baking soda and vinegar accordingly for a big eruption! Cut a hole in the top of the watermelon that is just big enough to scoop, but the smaller the hole, the better for your volcano eruption as the lava will all be forced up the hole. Scoop out the inside like you carve a pumpkin. The reason we scoop it out isn’t for the science experiment with watermelon, it is to avoid being wasteful with food! All we need for this watermelon activity is the watermelon container or shell, so to speak.
When you are ready for your eruption take your watermelon fruit outside or put it on a tray with the surrounding surfaces covered – just in case! Now add baking soda, dish soap, and red food colouring (the more the better for deep red colour).
NOTE: You don’t need the dish soap to make the summer science experiment work, but it will make it bubble!
Pour in vinegar, about 1-2 cups, until you get some fun fizz starting to come up.
The volcano will begin to fizz and flow the “lava” from the inside down the side of the watermelon!
If the children can’t get enough of this science experiment, it’s normal.
Just dump in more baking soda and vinegar, plus food colouring and dish soap if you wish. No need to rinse or clean the tray unless you are out of the room on the tray. That’s part of why we like to do our project outside.
So what is happening in this cool fizzy chemistry experiment? Basically, you are creating an acid and a base experiment. The vinegar is an acid and the baking soda is a base. When they mix they produce carbon dioxide. This fizzing gas will take up more and more space forcing the liquid in your watermelon to be forced up and out to create room for all the newly created CO2.
Encourages C&L, Science, UW