When planning your camping trip, you probably took a peek at the long term forecast on your local weather report. But sometimes nature likes to play tricks on even the most seasoned meteorologist. One way to keep an eye on the weather when you’re camping is to make your own simple barometer. A fun science project to keep kids occupied while you set up camp or make dinner, this project will allow everyone to predict the weather without a weatherman!
What you’ll need:
- Container – a small coffee can or glass jar
- plastic wrap or a small balloon
- scissors
- a straw
- tape
- index card or piece of cardboard
- marker or pen
- rubber bands
How to make it:
Cover the top of the container with plastic wrap. Pull it tight and secure it using the rubber bands. Make sure the plastic is completely covering the top of the container, making an airtight seal. You can also use a balloon with the end cut off so you are left with a piece of rubber wide enough to cover your container.
Place the straw horizontally on the plastic wrap, leaving the last couple of inches overhanging the edge of the can. Tape the straw securely to the plastic wrap to keep it in place.
Tape a large index card or piece of cardboard to the can behind the end of the straw. The straw will act as your gauge. Mark the starting point of the straw onto the card.
After 15-20 minutes, mark the new location of the straw on the index card. Continue checking and recording the straw location as often as you wish. Any movement of the straw indicates changes in the surrounding air pressure.
Here’s a video with all the steps:
https://www.youtube.com/watch?v=ah8F-xmvB2k
How a barometer works
A barometer measures changes in air pressure. Lower pressure indicates cooling air and possible incoming storms. Higher pressure means warmer, clearer weather. 
If the surrounding air pressure rises, the plastic will be pulled down into the container, and the straw will go up. A drop in the air pressure will cause the straw to go down.
Use your barometer in conjunction with your own observations of the skies at your campsite. If you know a storm is moving in, you can watch the changes as your straw goes up and down. A fun way to pass the time for any budding scientist in the group.
