Air Temperature and Humidity
Introduction | Cold Air & Humidity | Don't Let the Dog Out! | Cool It! | Worksheet | Team 7-1
Weather Simulator
1. What happens to the volume of air when it is heated?
2. What happens to the relative humidity when the temperature decreases?
(Look at the diagrams and answer the questions)
Air molecule diagrams
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Is the Air Temperature Cold or Hot? |
Is the Air Temperature Cold or Hot? |
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Explain Why.... |
Explain Why.... |
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Estimate the relative humidity |
Estimate the relative humidity |
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Is the Relative Humidity High or Low? |
Is the Relative Humidity High or Low? |
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As the air is (warmed or cooled) The relative humidity (increases or decreases) |
Introduction | Cold Air & Humidity | Don't Let the Dog Out! | Cool It! | Worksheet |
Weather Simulator
Instructions:
Use the simulator link to see what happens inside your house when the temperature and dew point change outside. Use the simulator to answers these questions:
1. What happens to the humidity in the house when you heat up the cold air?
(Answer the question after you collect data from the simulator)
Make the outside temperature cold (-10)
Turn off the furnace and open the door.
Readings Before Furnace was turned on.
Temperature ______ Relative Humidity _______
Now close the door and turn on the furnace.
Readings After the Furnace is turned on.
Temperature ______ Relative Humidity ______
2. Why do people run humidifiers in the house during the cold winter months?
Introduction | Cold Air & Humidity | Don't Let the Dog Out! | Cool It! | Worksheet
Weather Simulator
Use the facts below and the simulator to explain the statement
| It is below zero outside. Why do your parents complain, “Don’t keep opening the door and letting the dog out. It is too cold and the static electricity will ruin our computer!” |
Remember these facts
When air is heated it expands
The saturation point (moisture-holding capacity of the air) increases rapidly as the temperature of the air rises. Thus cold air, while its moisture content is necessarily quite low, may be almost saturated with respect to the maximum amount of water vapor it is capable of holding (high relative humidity). http://www.infoplease.com/ce6/weather/A0824520.html
Dry air can cause static electricity in an environment. Increasing the relative humidity of air can diminish static electricity. When the air is humid, water molecules can collect on the surface of various materials. This can prevent the buildup of electrical charges. Thus, static electricity is formed much better when the air is dry or the humidity is low. http://www.school-for-champions.com/SCIENCE/static.htm
Static electricity can cause damage to computers, dry your skin, create static cling on your clothes.
Use the simulator, collect data, and answers these questions
The Furnace is On
Thermostat is 70
Outside air is -10
Outside RH is 25% (Adjust the dew point until the RH = 25%)
Door is shut
- What will happen to the inside relative humidity if the door is opened?
Record readings from the simulator Before door opens After door opens
Inside Temperature Reading _________ _________
Inside Relative Humidity reading _________ _________
2. Why are your parents upset when you open the door and let the dog outside?
(Use the terms - relative humidity, temperature, and static electricity)
Include the answers to these questions: What will happen to the indoor relative humidity?
What might happen to the computer?
Introduction | Cold Air & Humidity | Don't Let the Dog Out! | Cool It! | Worksheet
Weather Simulator
Do air conditioners do more than just cool the air?
Use the simulator to collect the data
Make the outside temperature equal to 100
Adjust the dew point 80
Turn off the furnace and air conditioner
Open the door
Record the readings
Temperature ______ Relative Humidity _______________
Set the thermostat to 65
Then close the door and turn on the air conditioner
Record the readings
Temperature ______ Relative Humidity _______________
Answer the question
Include the words: temperature, relative humidity, hot, cold
Use data from simulator to justify your answer
Read this article from Air Conditioner Contractors of America.
- What other function do air conditioners perform besides cooling the air?
- What is the suggested comfortable indoor temperature and relative humidity for summer and winter?
Introduction | Cold Air & Humidity | Don't Let the Dog Out! | Cool It! | Worksheet
Information on this website adapted from Ackerman and Knox "Relative Humidity Exploration"
http://profhorn.aos.wisc.edu/wxwise/AckermanKnox/chap4/RelativeHumidity.html
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