Homemade Barometer Part 2

We had some excitement, and a setback with our first barometer.

First off, our balloon over jar, barometer seems to be working. It was pointing higher this morning than yesterday, and dropped a little, as clouds starting rolling in.

Then, we experienced our setback. One of the little ones, decided to pull the pointer straw off of the balloon. So, after a quick interrogation, and tearful confession, we had to start over, and re-glue the straw.

While we were at it, we decided to go ahead, and make our second, of what I think will be three, barometers. This time we loosely followed instructions from PBS's Rough Science site. It called for:

• a glass
  
• a bowl
  
• 4 paper clips (we substituted bobby pins)
  
• water
  
• and we added a couple inches of painter's tape

Start by placing the bobby pins on the rim of the glass, pushing them down as far as they will go, and spacing them an equal distance apart.

Stick the tape to the outside of the glass, about an inch down from the top. We used painter's tape, so it will be easier to remove later.

Fill the glass halfway with water.

Put the bowl, upside down, on top of the glass, and quickly flip the glass, and bowl over. Some of the water will escape from the glass, into the bowl, but that is okay.

Finally, mark the water level, on the tape.

As, the atmospheric pressure rises, it will push down on the water in the bowl, and cause the water level in the glass to rise. When the pressure is lower, that water will push out of the glass, and the water level will drop.

Or, at least that's what we've been told. Nasa's for Kids site, has a pretty nice explanation of what atmospheric pressure is, and how it effects the weather, if you're interested. And, in the time it's taken me to type all this up, the clouds have continued to roll in, the temperature has risen slightly, and both barometers have dropped. Which, if I understand everything correctly, means they are both working as expected.

It's great to be a homeschooler.