How to Make a Simple Air Barometer

Barometer is an instrument that was invented in 17th century used to measure atmospheric pressure. In laymen’s terms barometer measures the air pressure to determine the weather for near future. As there are many different types of barometers, we will be focusing on making a simplest kind, and that is air barometer.

Difficulty: Easy

Instructions

Things You'll Need:

• Sturdy canister with one open side, such as a pickle jar.
• Balloon
• Scissors
• At least one sturdy rubber band.
• Straw
• Little tape
• A helping hand

1. Go to your location. Understand that we will be creating a close pressure system inside the jar, thus it is important that you will make your barometer at the location of its intended usage. If you make it at lower altitude, where there is a higher pressure, and than take it to higher altitude, where there is lower pressure, the readings will be off.

2. Pick your time of the day. Keep in mind that high pressure is associated with bad weather and lower pressure is associated with good weather. If you build it during a bad weather the barometer will be calibrated to more bad weather. So, you have to pick a neutral day to get best readings.

3. Cut the balloon. Now that you know where and where you need to build your barometer lets get to the actual build. First cut off the mouth of the balloon. Do not cut too little as you will not be able to stretch it a lot.

4. Pull the balloon over the jar. Once the balloon is cut, grab it with both hands and stretch it over the open part of the jar. Careful so you do not tear the balloon if you have long fingernails. The balloon should not be stretched too lightly or too tightly, so that it rips. It should sound like a drum when you tap on it.

5. Secure the balloon with the rubber band. Once to have the balloon stretched over the jar just right, you need to secure it tightly with rubber band(s) on the jar. The rubber band(s) need to be tightly on, to create air tight container, but not to tight so they snap. You may cut the access balloon at this point if desired.

6. Test the seal if you want to. If desired you can dunk the entire jar under water or in the pond. Then lightly push the balloon in the jar. Careful so you do not puncture it. Do you see any bubbles? No, good! If you do you need to start over.

7. Attach the straw. Take one end of the straw and lay it flat on the balloon, so that the end is in the center. Next, take a piece of a tape and tape the straw to the balloon. Do not use superglue or hot glue as it will damage the balloon. Next, cut the other end of the straw on an angle so it created a makeshift arrow or point. Make sure that it sticks out at lease 2 (5 cm) inches from the edge.

8. Enjoy you new barometer. Keep the barometer away from windows or devices used for air treatment, such as heathers or air conditioners, as they can change the temperature, thus pressure, inside the jar and alter your results. If the arrow points up, the weather will not be preferable, however if it points down it should be sunny.

Tips & Warnings

• Always check you local weather service for most accurate weather forecasts.

[gables]

on 8/19/2009 i like your explinations. i think it's better than my easy barometer :(