# Weather at Home: How to make a barometer

This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

DENVER (KDVR) — If you are looking for an activity to help keep your kids busy and learning at home, you can try this simple science experiment: how to make a barometer.

This classic science experiment is sure to bring your kids hours of entertainment and can be made with common household items.

Here’s what you’ll need:

• Glass jar
• Ballon
• Plastic straw
• Rubber band
• Scissors
• Pen
• Paper
• Tape

Instructions:

1. Cut the neck of the balloon off and stretch it over the top of the glass jar. Make sure it is pulled tight
2. Secure the balloon in place around the top of the jar with a rubber band
3. Cut one tip of your straw at an angle to create a pointy end and tape the straw to the center of the balloon
4. On your piece of paper, draw a sun near the top of the page and a rain cloud at the bottom. Also make a mark on the paper where the straw is pointing

Now you are ready to observe the straw move up and down depending on how the pressure changes. If the straw points up from the center line, it means the pressure went up. If the straw points below the center line on the paper, it means the pressure went down. You kids can observe where the straw is for several days and weeks and notice different patterns in the weather depending on the pressure.

Here’s how it works:

A barometer is a scientific instrument that measures air pressure. Usually when there is high pressure in place, it means that the weather is warm and dry. When the pressure is low, there is a higher chance for cloud cover and storms.

In this experiment, once you place the balloon on the jar, it creates a seal for the air in the jar so the pressure will stay the same. However, the pressure outside the jar will be changing.

When there is high pressure in place, the outside air presses down on the balloon cover on the jar, causing it to cave in. This will make the straw point up or above the center line toward the sun on the paper showing you that the pressure is currently high.

When there is low pressure in place, it means that the air surrounding the jar will have less pressure than what is inside the jar. This will cause the air in the jar to press up and create a bulge in the balloon. This will make the straw point down or below the center line on the paper toward the cloudy and wet weather, indicating that the pressure has lowered.