Fun Online Homeschool Experiment Using Soda and Mentos
There are generally two types of changes: physical change and chemical change. The Seltzer Pressure Rocket experiment, whereby you pop a film-roll canister off its lid by adding an effervescent tablet to water, is a chemical reaction. When a firecracker bursts, there is a loud noise and a release of energy- again, a chemical reaction. However, the online homeschool experiment I will teach you is quite explosive, yet it is a physical change.
A physical change v guard gas geyser is one that does not involve any chemical combination, and no new substance is formed. A chemical change is actually a chemical combination of two or more substances to form an entirely different substance. For example, chopping a block of wood into pieces is a physical change whereas burning a piece of wood is a chemical change.
Today I am going to show you how to build a mento-soda geyser, an experiment that i have included in the online homeschool curriculum that i have designed. This is an experiment that has become one of my favorites, and I have performed innumerable times.
The Mento-Soda Geyser: Take a two liter soda (preferably Diet Coke) bottle and spill out some coke to leave an empty space at the top. Drill a hole in the cap of the bottle. Now take a roll of mentos mints and make holes in the center of each (about 8 to 10 mints). Take the help of an adult to drill the holes. Tie a knot to one end of a sewing thread and pass the thread through all the mints.
Pass this thread under the bottle cap and tape the free end of the string to the top of the cap in such a way that when you screw the cap onto the bottle the mints remain suspended in the empty space of the bottle just above the level of the soda. Your apparatus is now ready. Stand it securely in an open lawn so that it does not tip over. The best thing about online homeschool is that you can perform all your activities in and around your home.
Now when you are ready for the spectacular geyser display, remove the tape and let the mints fall into the soda. What do you see? The soda will be thrown into the air up to 10 to 15 feet high like a geyser. This will go on for about 15 to 20 seconds till most of the soda is spewed out.
How does this happen? In order to get the bubbly soda you enjoy, carbon dioxide is pumped into the liquid under high pressure. This carbon dioxide gas remains trapped in the liquid suspension and the bubbles are released when you pour the drink into a glass or when you shake the bottle.
There is enough tension between the molecules of the liquid to hold the bubbles confined. When you add the mints, this tension is broken by the sugar and gelatin in the mints. Carbon dioxide bubbles are released and get deposited in the tiny pores on the surface of the mint. These bubbles grow in size and are released out of the liquid. As there are many mints, the bubbles are multiplied and the pressure of the gas in the bottle begins to increase to such an extent that it escapes from the hole in the cap, taking with it the soda.