Do the Dew Point
Why do cold drinks “sweat” in hot weather?
What you need:
• metal can with label and top removed
• ice cubes
• room-temperature water
• thermometer
What to do:
1. Fill the can about halfway with room-temperature water. Make sure the outside of the can is dry.
2. Place the thermometer in the can and record the temperature. Leave the thermometer in the can.
3. Add a few ice cubes and stir. Carefully watch the outside of the can for "sweat" droplets to form. When they do, record the temperature. This is the dew point temperature.
4. Try this experiment under different conditions of humidity and temperature — outside, in a steamy bathroom, etc.
5. The dew point is the temperature at which water vapor in the air condenses to liquid. Does the dew point change under different conditions?
Learning benefits:
• observation
• measurement and recording
• experimentation
• understanding of condensation
| From The Wow's & Why's of Weather by Mary Kay Carson (Scholastic Professional Books) |
