Science Experiments With a Barometer

Barometers are tools to measure air pressure, and are used extensively in meteorology. If students have the chance to build their own barometers at school, they are more likely to understand how they work. Student can also make barometers on their own just for the fun of learning--here's how.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Glass jar
• Straw or plastic tubing
• Ruler
• Chewed piece of gum
• Permanent marker
• Tape

1. Put the glass jar on a table, desk or floor--the surface needs to be flat. Set the ruler inside the jar. Have the ruler's numbers facing you. The ruler should be placed in a way that has the 1-inch mark at the bottom of the jar--the numbers will get higher as they go up. Place some tape around the top of the ruler so that the ruler sticks to the jar. Make sure the tape is above the line that is going to have water near it.

2. Put the straw in the glass jar next to the ruler. Tape your straw to the ruler where the 1/2-inch mark starts. You don't want the straw to touch the bottom of the glass jar, so set it up a little higher.

3. Take your jar over to the sink and fill it about halfway up with water. If your jar is 12 inches high the water will come to the 6-inch mark. If your jar is smaller, you will have to divide the number in half to know how high to fill the water.

4. Stick a piece of gum in your mouth and chew it up. You may have to attempt this part more than once. Get some of the water up the straw by sucking on the straw. You don't, however, want the water to reach the top. When you get some water up in to the straw, close the hole in the straw up with your chewing gum. You may have to keep the chewing gum off to the side of your cheek while you are sucking on the straw.

5. Take a look at where the water is in the straw in relation to the ruler. Make a mark at that line with your permanent marker.

6. Use a notebook to keep tract of any changes in the water level. If it rises, mark that it did and to what measurement. If it decreases, mark that it did and the level on the ruler.

7. Predict the weather based on the readings you have on your barometer. If the water level has increased, you can predict that the air pressure is increasing. Increased air pressure brings about fair weather. When the water level drops, you can predict that the air pressure is decreasing. Decreasing air pressure brings about rain (clouds and precipitation).

Tips & Warnings

• This experiment should be done in the part of the classroom or room in your home that has a steady climate and temperature. You will not get accurate results if you don't' use a room with a steady temperature.