How to Make a Barometer

Did you know that you can make a barometer to measure atmospheric pressure at home? Many of the items you'll need can be found around the house, and the project won't take long. Learn how to make a simple barometer.

Things You'll Need

• Tape
• Tin can or an empty coffee can
• Rubber band
• Scissors
• 5" x 7" index card
• Plastic straw
• 12-inch balloon
• Pencil

Instructions

1. Gather your supplies. You'll need a tin can or an empty coffee can; a 12-inch balloon; a rubber band; scissors; a small plastic straw; tape; a pencil and a 5" x 7" index card.

2. Cut a large piece of the balloon using scissors. Stretch the balloon and wrap it tightly over the opening of the can.

3. Secure the balloon with a rubber band. Make sure that no air can pass into the can, as this will affect the results of your barometer.

4. Tape the straw to the center of the balloon so that part of the straw is hanging off the can.

5. Tape the index card to the wall.

6. Place the can next to the wall so that the straw is pointing toward the index card.

7. Mark the index card with some equally spaced lines above and below where the straw is pointing.

8. Observe the card every day for a week and record the changes that you notice. See if the straw points above or below the point that it showed the previous day. If the straw points above the previous day's point, it indicates a rise pressure. If the straw points below the previous day's point, it indicates a drop in pressure.

Tips & Warnings

• Notice the weather in relation to the barometer readings. This will help you understand the effect of atmospheric pressure on the weather. Low pressure is associated with rain or clouds while high pressure is associated with clear weather.

• Use the barometer both indoors and outdoors.