Homemade Barometer Part 1

I realized with a start, that we let a perfectly good, stormy spring pass by without doing any kind of real weather study. We did quite a bit with wind, last summer, but very little with weather prediction, so I thought, before summer got away from us, we might start with making a simple barometer. We're moving into some real thunderstorm weather, so it might prove useful.

I was still formulating my plan of action, when I became aware I had a 12 year old with time on his hands this morning, looking for something to do, so we plunged right in, sort of half prepared.

We opted to make the balloon on jar type of barometer, but we might yet try a liquid filled type, too. I'm not sure who to credit with the design, we saw it on several sights, including on PBS's Zoom. But, it's pretty simple to put together. It requires:

• a largish balloon
• a glass jar (wide mouth is good)
• a rubber band
• a straw
• paper
• scissors
• glue
• tape

Just cut the neck off of a balloon.

Stretch the neckless balloon over the mouth of a jar. The jar should have a wide enough mouth, so the balloon fits tightly.

(We also discovered this makes a very good bongo-type drum).

Secure the balloon to the jar, with a rubber band.

Glue a straw to the balloon, starting at the midpoint, so the straw extends past the edge of the jar, a couple of inches. We also trimmed the end of the straw to make it pointy.

Tape a piece of paper to the wall, behind the jar, and point the straw at it.

We started with the straw pointing sideways at the paper, but decided it was too difficult to tell where the straw was pointing, because depending on where you were standing, it looked different.

Then, we turned the jar, so the straw pointed directly at the paper, and marked where it was pointing with the time, and date. Finally, we recorded the time, date, temperature, and general cloud state (which this morning was partly cloudy), in a separate notebook.

The idea is when it's sunny, and generally high pressured out, the atmospheric pressure should push down on the balloon, causing the straw to point upward a little. When it's cloudy, and low pressured, the straw will drop. After recording our findings over the next few, hopefully varying days, we'll be able to mark high, and low spots on our wall chart, and be able to predict by looking at our barometer, what kind of weather to be expecting.

I've got my doubts about this model, so as I said, I think we'll follow it up with an additional type. But, either way, I hope to report back on our findings, and some additional weather related projects, later in the week.

It's great to be a homeschooler.