Insolation
Ch.8, Weather
Lesson 1, Atmosphere and Air Temperature
Atmosphere
Troposphere
Objectives:
 Explore how the angle of light affects temperature
 Identify factors that affect temperatures on Earth
 Explain how the atmosphere changes with elevation
 Identify conditions that make up the weather
Air pressure
Weather
Barometer
Main Idea: The Sun warms Earth’s surface which transmits heat to the air.
1. Does the Sun’s Angle Matter?
a. Where do we find warm temperatures year long? The equator
b. Where would we find cold weather? Near the poles
i. The angle at which sunlight hits a region makes a difference in
temperature.
ii. Areas around the equator are warmest because the Sun’s path
is high overhead at midday.
iii. Areas around the poles are coldest because the Sun is much
lower at midday.
1. The Suns angles are lower, and so is its strength.
c. Insolation – is short for incoming solar radiation.
i. It means the amount of the Sun’s energy that reaches earth at
a given place and time.
ii. The greater the angle of the sun, the warmer a place will be.
iii. This means while it’s freezing cold in one part of the world, it’s
hot in another.
How do differing angles of insolation cause differences in warming?
Areas with a higher angle of insolation receive more direct sunlight.
The poles receive the same amount of light, but it is less direct than at the
equator. Light at the poles is slanted and spread over a larger area and less
intense.
2. What affects insolation?
a. The higher the Sun is in the sky, the shorter the shadow.
b. How does time of day affect the angle of insolation?
i. Sunlight is most direct at midday
ii. The angle of insolation is less before and after noon.
3. Why do some things get hotter than others?
a. Dark colors get hotter than light colors.
i. Asphalt roads and dark soil gets very hot.
ii. White sand and light colored soils do not get as hot.
b. Texture – is how smooth or rough a surface is.
i. Rough textures cause light to bounce around at many angles.
ii. Rough textures tend to get hotter in sunlight than smooth
surfaces.
c. Swimming
i. When we go swimming the water is cooler than the air.
ii. It is cooler because even though the same amount of light
energy will heat land to a higher temperature than it will heat
water.
d. It takes more heat to raise the temperature of water than it takes to
raise the temperature of land.
How do color and texture affect the amount of heat absorbed?
Darker colors absorb more heat than light colors. Rough textures cause light
to bounce around, allowing more heat to be absorbed.
4. Why do you go cool down as you go up?
a. The higher you go above sea level, air temperatures drop.
b. Climbing up a mountain is really a journey into the atmosphere.
i. Atmosphere – the air that surrounds earth.
c. Temperatures do not drop as you continue higher into the
atmosphere, they change several times.
d. Troposphere – the layer closest to Earth and where all weather
happens. All life exists here.
What is the relationship between altitude and temperature?
In the troposphere, as altitude increases temperature decreases.
5. What happens to the Air pressure?
a. As you go higher in altitude, air pressure decreases.
b. Air pressure is the force put on a given area by the weight of the air
above it.
c. Air is made of molecules, mostly nitrogen and oxygen.
i. These molecules are attracted to earth by gravity, so they have
weight.
d. Normal air pressure is greatest at sea level.
e. Water vapor is a gas, not to be confused with clouds or fog.
How does the air pressure change with altitude?
As altitude increases, air pressure decreases.
6. What is weather?
a. Weather is simply what the lower atmosphere, or troposphere, is like
at any given time and place.
b. Measure temperature
i. Thermometer – Celsius or Fahrenheit
c. Measuring Air Pressure
i. Barometer – mercury and aneroid.
What conditions make up weather?
Air temperature, air pressure, wind, amount of moisture in the air, clouds,
and rain or snow.
Review Questions and Answers
1. How do temperatures on Earth depend on angles?
The angle at which rays of the Sun strike a surface affects how much
heat it will receive. The more vertical the rays the greater the heat.
2. List factors that affect temperatures of places on Earth?
Angle of insolation
Water
Plants
Altitude
3. What is air pressure?
Air pressure is the force on an area caused by the weight of air above
it. It is greatest at sea level and decreases with increasing altitude.
4. What is the troposphere?
The troposphere is the lowest part of the atmosphere. Most air is
found and most weather occurs in the troposphere.