Materials: small bottle (a water bottle works great)
balloon
baking soda
vinegar (white vinegar is cheapest)
hot water
cold water
effervescent tablets, such as Alka Seltzer (optional)
This project
is all about experimenting, so the proportions of baking soda and
vinegar to use are just suggestions; feel free to let your kids go
crazy with it!
The basics
are this: Fill your bottle about 1/3 full with vinegar. Use a spoon
or funnel to put about 2 tablespoons of baking soda into the
balloon. Now carefully place the opening of the balloon over the
mouth of the bottle, being careful not to spill the baking soda into
the bottle. (The bulk of the balloon will hang off to the side.)
Make sure the balloon is on the bottle securely. Now tip the balloon
up so that the baking soda falls quickly into the vinegar into the
bottle. Watch as your balloon fills up with CO2 gas!
You can also
experiment with the impact of temperature on acid base reactions by
using the same procedure to drop effervescent tablets into hot or
cold water.
The
Science:
When an acid
(such as vinegar) and a base (such as baking soda) combine, a
chemical reaction occurs that releases CO2 gas. This gas is safe; it
is the same gas that humans breath out of their lungs.
The faster
the reaction, the quicker the gas is released. Temperature affects
the speed of chemical reactions: heat speeds up reactions and cold
slows them down.
Effervescent
tablets have both an acid and a base in them. They do not react,
however, until they are dissolved in water and released into the
solution together.
