What makes it foggy outside?
As I was driving into work this morning, oh my was it foggy! Despite trying to see where I was driving, it made me wonder about (of course), how could I replicate this for the class I was going to see in a little while as I thought they may miss out on such an exciting weather phenomenon. I think I have it figured out and wanted to share it with you as well. Let’s get started!
*Remember to ask an adult before doing this experiment.
Materials
• 1 large clear heat proof glass jar
• 1 rubber glove
• Water
• Matches
• Adult helper
Procedure
1. Put enough water in the jar to just cover the bottom.
2. Hang the rubber glove in the jar with the fingers dangling downwards. Use all of your strength and stretch the open end of the glove over the mouth of the jar to seal it.
3. Put your hand in the glove, make a fist, and quickly pull it out. Be careful not to break the seal. Now let the glove snap back into the jar. Observe. What happens?
4. Remove the glove and HAVE AN ADULT light the match. Quickly and carefully drop the match into the jar and replace the glove resealing the jar.
5. Repeat step 3. What happened this time?
Explanation
I am sure you were a bit disappointed as at first nothing happened. The second time you repeated the experiment it is a different story! Once the match is put in the jar and you pull the glove outwards fog instantly forms inside the jar. When the glove snaps back into the jar the fog disappears. Hmm, how does this work?
Well, water molecules are present in the jar in the invisible form of water vapour. When you pull the glove out of the jar the air inside expands, and cools and the molecules all move slower. When the water molecules slow down they are able to stick to each other more easily, and they group into little droplets. The smoke from the match helps this process by providing a solid particle for the water to bind to. When you push the glove back in the air compresses and warms up, so the tiny droplets evaporate and become invisible again.
Patty Rooks, senior scientific consultant PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, www. praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: 12 826 11th Street SE, Medicine Hat, AB, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca.