Make a Barometer (Weather Instrument)

A BAROMETER is a weather instrument that measures air pressure.

Barometers record air pressure, which is the weight of air pressing down on the Earth's surface.

Here are directions to make a simple basic barometer. It will record if the air pressure is rising or dropping.

Materials

• recycled small clear plastic bottle
• bowl
• 3 pencils
• water
• food coloring
• clay
• tape
• marker

Directions

• Tape 3 pencils to the outside of the plastic bottle. Make sure the ends of the pencils are even and stick out above the top of the bottle.
• Put a small mound of clay on the end of each pencil.
• Half fill the bowl and the bottle with water. Add food coloring if desired.
• Cover the mouth of the bottle with your hand then carefully turn it upside down and place it in the bowl.
• Mark the water level in the bottle with a small piece of colored tape or a permanent marker.
• Each morning and afternoon check the water level. Is it the same or is it above or below the mark on the bottle.
• Record the data in a science notebook/journal.
• Compare morning and afternoon readings.
• Compare different days.
• Graph the data.

Explanation

Air presses down on the water in the bowl. The barometer measures air pressure.  If the air pressure rises, then the air pushes down harder on the water and the water level will rise SLIGHTLY higher. If the air pressure drops, then the water level drops SLIGHTLY lower.

  Have fun learning about weather.