Do Now

1. How do you tell when it is humid outside?

2. What do you know already about humidity?

Objective: I can explain that relative humidity compares the actual amount of water vapor in the air to the maximum amount of water vapor by creating a barometer.

Agenda

• INM Humidity and Relative humidity• Relative humidity lab• Brainstorm for writing

Moisture in the Atmosphere• When the air is holding as much moisture as it

can, the air is saturated– The air’s ability to hold water vapor depends upon

the temperature– The warmer the air, the more moisture the air can

hold

Moisture in the Atmosphere

• The dew point is the temperature to which the air must be cooled to become saturated– If the temperature falls below the

dew point, condensation occurs as water vapor changes to liquid water

Relative Humidity• Compares how much moisture the air is

actually holding with how much moisture it could hold if the air were saturated– It is expressed as a percent of saturation

• Air is saturated if it is holding all the moisture it can hold at its present temperature

• Determined with a psychrometer and a relative humidity table

Relative vs. Absolute

• Humidity

• Relative Humidity

• Absolute Humidity

Moisture in the air

A ratio of the amount of moisturein the air

The actual amount of moisturein the air

SameABSOLUTE Humidity

4 moleculesof water ðò

SameRELATIVE Humidity

ñï ½ filled

with water

Relative Humidity lab

• Please do not break my thermometers.

Brainstorming for our writing task

• You’ll be working on your writing task this week.– You will NOT be getting enough time to finish this

in class. – However, I want you all to have an idea about

where you are heading with this task.

Writing prompt

• Think about what you’ve been learning this quarter in science (weather, atmosphere). Think about a specific time or place in which you have been impacted by natural elements or forces nature or other topics you’ve learned about this quarter in science. Perhaps the weather has interrupted a sports event like a soccer match or the drought has caused foods you like to go up in price. Write a multiple paragraph essay describing how scientific concepts you have learned about have impacted or changed your life in some way. Make sure the main ideas are thoroughly supported with details and examples of how science has impacted your life.