1. Finding the Dew Point Materials: Beaker, water at room temperature, ice cubes, thermometer
Directions: Fill a beaker with water, half full, and record the temperature. Make sure the outside of the beaker is dry. Then slowly add ice cubes to the beaker, while continually stirring. Constantly feel the outside of the beaker for condensing water. When moisture condenses on the outside of the beaker, record the temperature of the water. This temperature is the dew point in the classroom.
After Lab Questions: 1. Why does the atmosphere reach its dew point? 2. Explain why the dew point may not be the same if this experiment was performed on a different day or in a different location. 2. Cloud in a Bottle Supplies: textbook, bicycle pump, rubbing alcohol, 3-liter, valve stem, goggles, and Mr. Jacobs
Directions: GOGGLES ON! MR. JACOBS MUST SUPERVISE THIS EXPERIMENT! NOTE: YOU MUST HOLD THE STOPPER AND 3-LITER AT ALL TIMES. THE DEPRESSURIZATION IS EXPLOSIVE. Pump into the 3-liter 45 psi. Then quickly release the pressure from the 3-liter by pulling out the rubber stopper. You will see a cloud form inside. Repeat the steps to see the cloud disappear and reappear. Questions: 1. What happened to the air pressure and temperature inside the bottle when you pumped it up? 2. What happened to the air pressure and temperature inside the bottle when you released the pressure? 3. Beyond cooling, what else do you need for a cloud to form? Knowing this, what must have been inside your bottle? 4. How did the lab prove what the readings said about how clouds form? Don’t forget to mention cooling, particulate matter (i.e., dust particles in air), and water vapor. 5. On days when you are in a zone of high pressure, are you more likely to have clouds or clear skies?
3. Precipitation Video Directions: Watch the video and take the quiz.
Questions: Take the quiz.
4. Fog in a Glass Directions: Complete the “Discovery Activity” (i.e., How does fog form?) on page 560.
After Lab Questions: 1. Explain how this lab simulates how fog forms. 2. Why is there a difference between what happened with the hot water and the cold water? 3. Prove that particulate matter or nucleation sites are in the air around us. In other words, give a real-life example of how people collect dust / particulate matter out of the atmosphere.