Build a Barometer

The Monday before our Thanksgiving Holiday, the Physical Science class and I, decided we didn’t want to have an hour and half of lectures from me, on Module 7.  So….we built a barometer.    The instructions for this project comes from Bill Nye, The Science Guy’s Big Blast of Science book.

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A clean jar
A balloon
Drinking straw
Rubber cement
Rubber band
Long piece of wood

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Make sure you read the Danger Warnings on the Rubber Cement: Extremely Flammable (don’t say that in front of students who like fire), Avoid inhaling vapors, may result in nausea, headache, confusion or instability (much like a normal teenager), harmful or fatal if swallowed. Other than that, it is harmless. 😀

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1. Cut the neck off the balloon.
2. Paint the jar’s rim wiht the harmless rubber cement.
3. Stretch the balloon over the mouth of the jar, and hold it flat with the harmless rubber band.
4. Snip the end of the straw at an angle so that it froms a sharp pointer.
5. Tape the straw to the balloon so it sticks out to the side of the jar. Make sure the taped end is near the middle of the balloon, not the edge.
6. Using the rubber band and the harmless rubber cement, seal the balloon so no air can get past it into or out of the jar.

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7. Tape the jar to a long piece of wood.
8. Stand a ruler against the wood near the straw. Don’t let it touch. Tape it firmly to the board so it can’t slip. We used a paint stick.

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Since we didn’t have a ruler, we made a mark on the stick where the point of the straw was located. We are so very scientific professionals here.

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Waaa-Laaah: you have a Barometer.
9. Put the jar somewhere where the temperature will stay the same.
10. Note where the straw is pointing. Mark in a different color.
11. Check often and mark with different colors, where the straw is pointing. Make note of date, time, and color marker used in your lab book.
12. You can take your Barometer to different levels, to watch the difference in pressure. Going up in a tall building will change the pressue in the barometer.

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Due to extreme Scientific Error, our experiment did not work. But, we had fun!

What happens: The pressure in the jar will cause the balloon to swell out our sink in, thus causing the straw to move up or down. 

Some history:  Italian physicist Evangleista Torricelli invented the barometer in 1643.

Other barometer experiments to try: Miami Science and A Weather Station

How to build a working barometer.

7 responses to “Build a Barometer

  1. What I want to know is where did you get that pointer? That is a riot!

    It looks like a fun activity, M! Maybe your hubby with his very fine garage toys can cut a slot in the wood for the paint stick.

    My youngest loves that harmless rubber cement. The first thing he said, “ooo, I like it’s smell”. Give me that back, Kid!

  2. LOL, Sheri that pointer is Fred the Finger. I got it at a local school store. The kids fight over it. I usually won’t allow anyone, but myself to use it. One of the boys wanted to use it for the pictures that day.

  3. Very cool experiment 😀

    I like your pointer, I’ll have to look for one of those for me. 😆

  4. hey this website is cool! I had to make a barometer for a science project and these instructions were helpful.

  5. awesome! just what i needed for my science project!!!!!!!!!!

  6. Thanks so much for saving our co-op class from a Physical Science module without an experiment!

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