Make Your Own Barometer

by Don
(NJ)

I love using little things around the house to teach my kids about the world around them. Recently when watching the weather I decided to build a homemade barometer.


The list of materials you need is very simple:

- Bottle with a narrow neck
- Clear straw or thin tube
- Rubber stopper
- Window sealant
- Water
- Food Coloring


Method

The first and trickiest part of the entire process was boring a hole through the rubber stopper that a straw could fit into tightly. I made a couple mistakes with this part, so I would suggest getting a few stoppers so that if you ruin one, you have a backup.

Put a hole in the stopper and fit the straw or clear tubing into it. Rubber works well for this because it is more likely to seal out air. Once you have completed this, grab the bottle.

I went to the store and found a glass soda bottle with a narrow neck on it to use for building the homemade barometer. The clear glass makes it easy to see what is going on inside. Fill the bottle a little over half full with water and add some food coloring. I let my kids choose the color and we ended up going with blue.

Place the straw into the water and put the stopper into the bottle. Then blow some bubbles into the bottle, making sure the end of the straw stays below the water level. Hopefully the air will stay in the bottle, and the colored water will rise into the straw. If this happens, you did it right! Seal the stopped with some of the window sealant to keep any slow leaks from occurring.

Now my kids check the homemade barometer every day. We have to remake it occasionally to keep the water level up, but they are learning that the higher the water is in the straw, the lower the atmospheric pressure is. This has led to more interest in the weather and now my kids keep pestering me to make more experiments similar to their homemade barometer.