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Sent in by:
Amy of Walpole, MA

Oh, the air pressure! Build a gadget to measure it.

Materials Needed

  • large jar. A spaghetti sauce jar works well.
  • 2 straws
  • balloon
  • small triangle cut out of poster board or construction paper
  • rubber Bands
  • ruler
  • paper



  1. Cut the neck off of the balloon.
  2. Stretch the balloon over the opening of the jar.
  3. Secure it with a rubber band.
  4. Tape the two straws together.
  5. Tape one end of the straws to the top of the balloon stretched over the opening of the jar. The straws should stick out about 8 inches perpendicularly from the jar.
  6. Tape the small triangle to the end of the straws to make a pointer for your barometer.
  7. To make a scale, cut a piece of paper so it measures 30 by 6 centimeters.
  8. Starting at the bottom of the paper, mark 21 lines that are one centimeter apart all the way up the paper.
  9. Again, starting at the bottom of the paper, label the lines from 1 to 21.
  10. Hang the scale on the wall. Put the barometer next to it, with the pointer lined up with the 11 line on the scale.
  11. To record your data, make a chart that has columns labeled: Date, Barometric Reading, Weather Today.
  12. Each day, look at where the pointer of the barometer is pointing to. Then, on your chart, write down the number along with the date and the weather. Soon you'll see a pattern.

When the pointer on your barometer is pointing at the high numbers it shows that air pressure is pushing down a lot on the balloon. When the pointer on your barometer is pointing at the lower numbers, the air pressure is not pushing that hard on the balloon. So, usually when you have high pressure you have nice, sunny weather. When you have low pressure, you have rainy weather.

You can also send us your pictures or video of this ZOOMsci:
Box 350
Boston, MA 02134

Some of your Results

Chelsea, age 13 of Denver, CO wrote:
This barometer did not cooperate very well. It stayed on 11 the whole time!

Lauren, age 13 of Henderson, TN wrote:
I got the low pressure and high pressures but once it was in the middle.

Gillian, age 12 of Springfield, OH wrote:
It rally worked! Maybe I think, but I couldnt get an accurate pressure compared to the real ones.

Emily, age 13 of Mesquite, TX wrote:
It did not work at all! I don't know what happened. But we changed the design 15 times it just wouldn't work!

David, age 10 of Campbell, OH wrote:
The air in the barometer pushed up the baloon top and made the straw move to the number on the peice of paper.

Chelsey, age 11 of Woodstock, IL wrote:
I think it worked really well when I tried it. I used it April through August, when it popped. It was quite helpful, because our teacher taught us that low pressure means a storm of some kind, so I could tell when a thunder storm was coming.

Steven, age 11 of Canton, MI wrote:
It worked out great. I tried it for my project and I got an A on it. It was accurate most of the time and sometimes I was a little off.

Shriya, age 8 of Sunnyvale, CA wrote:
When you made the barometer, what pressures did you record and how did you analyze your data? I have made a barometer myself and I think that yours worked better than mine did. The projects that you make on the show are very cool and obviously practiced.

Margarita of Baldwin, NY wrote:
I loved this experiment! I guess it was a very sunny day out when I did this experiment because the balloon got so full, it poped!

Jarred, age 9 of Olathe, KS wrote:
When I tried this experment, It worked!!! It went up on sunny days and down on rainy days. I want to be a meterologist when I grow up, so I like it.

Aksa, age 11 of Norwich, CT wrote:
Well, I tried making the barometer and it was alot of fun. Then I told my teacher about it and she loved it and I mean she loved it so much she said that she is going to use it next year. I got a A+ on my Science grades. Thanks for inventing the Barometer.

Jarred, age 9 of Olathe, KS wrote:
It worked!!! I made a chart and recorded the barometric pressure.

Dheevena, age 12 of Ft. Wayne, IN wrote:
I used it for Science Fair because I was talking about weather and I tested it myself. I loved it! Maybe I could make my own weather channel!!!

Tricia, age 13 of Linville, NC wrote:
This project was so neat! It actually worked when I tried it, and I entered it in the science fair and got 3rd place!(and it is SO hard to actually get a place in our science fair)

Bronwyn, age 9 wrote:
I liked the barometer a lot! And it worked really well! I love show keep it up!!!

Tianna, age 9 of Columbia, SC wrote:
I collected my data and at certain days there was bod and good weather.

not yet implemented