Brewing up the invisible
FREE Science for Seniors activity - Making the invisible visible! Halloween is almost here. Many of our superstitions come from a time when in an attempt to explain the unknown people would say "the spell of a witch made you sick." Later when humans were first expose to the idea of 'invisible' germs many balked. How can something we can't see hurt us? And yet we breath because of the oxygen in the air which we can not see.
Here is a fun way to make the normally invisible to the human eye become visible.
Materials: 18 inch stick, table, two plastic bags, tape, thumb tack, glass, vinegar and baking soda.
Process: Attack the plastic bags to the ends of the stick with tape with the opening the same on each of the stick. Hold the stick on place with a thumb tack balanced on the edge of the table. Pour vinegar into the glass. Add baking soda to the glass. Tilt the glass over the opening of one bag and observe.
Result: The vinegar and baking soda form carbon dioxide gas. This gas is heavier than air. When you tilt the glass over one bag, you add the carbon dioxide and the weight of the gas makes the bag heavier and drops the bag downward.