March 21, 2020
We’re going to have some temperature swings this weekend — you can make your own weather instrument to measure the atmospheric pressure with just a few supplies like this one that Kirsten, one of our museum educators made at home!
The air around you has weight and presses against everything it touches — that pressure is called atmospheric pressure, or barometric pressure, and it’s a pretty good indicator of the weather! When a low-pressure system moves into an area, it typically leads to cloudiness, wind, and precipitation. High-pressure systems typically lead to calm, fair weather..
What you'll need:
A glass bottle with a straight (not curved) neck
A glass jar with an opening small enough that the bottle can go in upside down without the opening touching the bottom of the jar
A rubber band or hair tie
Let’s get started:
1. Turn the bottle upside down and put it inside the jar.
2. Note where the bottle opening sits.
3. Fill the jar with enough water to cover the opening of the bottle, plus an inch or so.
4. Remove the bottle and add a few drops of your favorite color of food coloring to the water. Give it a gentle stir or swirl!
5, Put the bottle back in the jar. With both hands, tilt the jar and bottle so the bottle releases some of the air from its neck. You should see a few bubbles.
6. Mark the height of your water by placing the rubber band around the jar, lining up the rubber band with the water level.
7. Place your barometer outside in a shady, protected area like a porch or covered patio where it won’t get direct sunlight. Your barometer is now ready for use!
When air pressure is lower it doesn’t push down on the water in the jar as hard, so the water in the jar rises higher than the rubber band. Low pressure is often an indication of stormy weather coming. When the water level sinks below the rubber band, a high pressure system could signal improving weather!
If you make a barometer at home, show us with #SMOatHome!