- Step 1: Wash bottle and jar Wash a 12-ounce clear glass bottle that has a straight neck and an 18-ounce clear glass jar, making sure to remove any labels.
- TIP: An empty 18-ounce peanut butter jar is a good choice for this barometer project.
- Step 2: Assemble barometer Assemble the barometer by first placing the bottle inside the jar in an inverted position. Fill the jar with just enough water to come up over the mouth of the bottle by an inch or so.
- Step 3: Add food coloring Add a few drops of food coloring to the water before slightly tilting the jar to allow air bubbles to release from the bottle.
- Step 4: Place rubber band Place the rubber band around the outside of the jar at the water level.
- Step 5: Find a station spot Find a spot to set up your barometer station where it's not exposed to direct sun, artificial temperature changes, or in a location where it could be accidentally tipped over.
- Step 6: Observe water levels Observe water levels rise as air pressure rises to predict fair conditions, and drop as pressure falls to predict rain. Now, you'll never have to look farther than your own barometer station to forecast the next picnic day or when to pack an umbrella.
- FACT: Since 1977, Banner Elk, North Carolina, has celebrated the weather-predicting wooly worm with an annual festival.
You Will Need
- straight-neck glass bottle
- Clear glass jar
- Food coloring
- Rubber band
- Appropriate place to station the barometer