- Glass Measuring Cup
- Soda Bottle
- Colored Dye
- Fill the glass measuring cup with water.
- Add the colored dye to it
- Put the soda bottle into the glass measuring cup – upside down!
- Be sure the mouth of the soda bottle doesn’t touch the bottom of the glass measuring cup. The neck of the bottle should rest on the top of the glass measuring cup.
- Look inside the soda bottle. Does the water extend at least into the neck of the bottle? Make sure it does!
- Use the marker to draw a line to show the exact level of the water in the soda bottle.
- Wait a few days and go back to see where the water level is located at.
The water inside the soda bottle is trapped! No air can get inside it. If the water level is higher than the marked line, that means the air pressure has increased. If the water level is lower, that means the air pressure has decreased and you should prepare for rain!!
LOOKING DEEPER INTO AIR PRESSURE
- The air inside the soda bottle is unchanging. The water is somewhat of a ‘cork’. It stops the air from going anywhere.
- The day you corked the bottle is an indication of the air pressure for that day.
- Any daily pressure change will affect the air pressure inside the soda bottle.
- When the air pressure increases, the pressure on the top of the water increases as well, and the water is forced up inside the bottle.
- When the air pressure decreases, the pressure on the top of the water decreases as well, and the water is forced down.