Download air pressure and the greenhouse effect

Directions: Read through the following experiments and perform them as indicated. Take notes
or somehow record your observations. When finished answer the questions at the end. Turn the
question page(s) into your teacher.
The atmosphere performs a multifaceted role—it shields the earth from meteorites, protects it
from many harmful rays in space and houses the gases that make life possible. Several
atmospheric experiments can be demonstrated within the confines of a classroom. Atmospheric
experiments allow us to learn about clouds, weather, climate, pollution and even the sun’s effects
on the planet.
Air Pressure Experiment 1
Air pressure is a key concept related to the atmosphere. Acquire a glass jar, tea candle, matches
or a lighter, a shallow pan, and water. Fill a shallow pan a quarter of the way with water. Invert a
glass jar over a burning candle in the shallow, water-filled pan. The jar should be standing upside
down on a shallow pan of water, over a lit candle. This is a simple demonstration of atmospheric
pressure. The flame should go out as it uses up the trapped oxygen. The vacuum causes a change
in air pressure, causing the water level inside the glass jar to rise. The phenomenon occurs
naturally in weather fronts, where warm air meets cold air. Hurricanes, for instance, build up as
air rises from a warm body of water and creates a low-pressure area.
Water Vapor Experiment
Clouds are another natural phenomenon with which students are familiar. Clouds form when
water vapor is present in pressurized atmospheric conditions, along with dust particles in the air.
This can be demonstrated by filling a third to half of a glass jar with warm water. Spray
hairspray in the open space that the water does not fill. Then place the glass jar’s lid upside down
on the top of the jar (creating a tiny bowl). Fill the jar’s lid with ice. Watch your cloud form.
carefully observe the artificial “clouds” appearing as the warm water vapor rises, then cools as it
nears the ice at the lid. Water droplets will condensate on the hairspray particles as they cool.
Greenhouse Effect Experiment
A discussion of the Earth’s atmosphere is not complete without discussing climate change.
Several experiments can be used to illustrate the greenhouse effect. In a simple setup, place in
the sun a dark-colored basin holding a thermometer atop an inverted paper cup. Covering the
basin with plastic wrap will result in a higher temperature reading because heat is trapped by
greenhouse gases inside. Repeat this experimental setup without the plastic wrap. The same
principles can be observed in a parked car that absorbs short-wave energy through the windows
as it sits under a hot sun. This results in the interior giving off long-wave infrared radiation,
much of which is trapped within the vehicle.
Air Pressure Experiment 2
Another type of experiment is very easy to do and can even be performed with a glass cup filled
roughly to one-third with water, grab a coaster and cover the opening. Press it firmly to the glass
and then tilt it upside down. Now you can let go of the coaster and it should stick. The reason is
the air pressure pushes up through the glass with close to 15 pounds of force.
Directions: Read through the following experiments and perform them as indicated. Take notes
or somehow record your observations. When finished answer the questions at the end. Turn the
question page(s) into your teacher.
Questions:
1. In Air Pressure Experiment 1, is their more oxygen inside or outside the glass jar?
2. Why does the flame dissipate in Air Pressure Experiment 1?
3. Which natural phenomenon relies on the principles shown in Air Pressure Experiment 1,
where air rises as it heats up over a warm body of water, creating a low pressure area?
a. Dust storm
b. Hurricane
c. Whirlpool
d. Aurora borealis
4. In what layer of the atmosphere would the natural phenomenon identified in question 3
occur?
5. Name a greenhouse gas.
6. What part of the stratosphere keeps out harmful ultraviolet rays, and when damaged can
add to the greenhouse effect?
a. The ionosphere
b. The thermosphere
c. The ozone layer
d. The troposphere
7. What substance acted as the dust particles water vapor clings to in the water vapor
experiment?
Directions: Read through the following experiments and perform them as indicated. Take notes
or somehow record your observations. When finished answer the questions at the end. Turn the
question page(s) into your teacher.
8. What process occurs as warm air rises and cools, going from a gas to a suspended liquid?
a. Evaporation
b. Transpiration
c. Precipitation
d. Condensation
e. Runoff
9. Based on the information you have gained from air pressure experiment 1 and 2, do you
think there is more air pressure in our lungs or outside our body during inspiration
(breathing in)?
10. In the Greenhouse Effect Experiment what did the dark surface of the basin represent
a. The atmosphere
b. The surface of the Earth
c. The oxygen in the air we breathe.