sci_207_lab_5-1.pdf

Lab 5 Weather and Climate Change

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Weather and Climate Change

Introduction

The Earth’s atmosphere is composed of 21% oxygen (O2), 78% Nitrogen (N2), and ~1% other gases

(including water vapor, argon, carbon dioxide, hydrogen, and helium). Oxygen is essential for life and is used

by most organisms for cellular respiration while carbon dioxide is used by plants and certain bacteria for pho-

tosynthesis.

Our atmosphere is composed of five layers:

1. Troposphere - nearest to the Earth’s surface; layer in which weather occurs (rising and falling air);

comprises one half of total atmosphere; air pressure is decreased to 10% of that at sea level.

Concepts to Explore

 Atmosphere

 Weather

 The Water Cycle

 Climate

Figure 1: Clouds are visible accumulation of water droplets that accumulate in the Earth’s lowest

layer of the atmosphere, the troposphere.

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Weather and Climate Change 2. Stratosphere - contains the ozone layer (important for UV ray absorption).

3. Mesosphere - layer which meteors burn up in upon entering the Earth’s atmosphere.

4. Ionosphere/Thermosphere - locations of auroras (e.g., aurora borealis); layer in which the space shut-

tle orbits.

5. Exosphere - upper limit of the Earth’s atmosphere; layer where Earth’s atmosphere merges with outer

space.

Weather is the state of the atmosphere at a given time and place and includes temperature, pressure, the

type and amount of precipitation, wind, clouds, etc. Weather conditions can change hour to hour, day to day,

and season to season. Our weather is caused by uneven heating of the Earth from the sun. The resulting

temperature differentials generate wind that forces warm air to flow to regions of cooler air. This flow can oc-

cur both horizontally across the surface of the Earth (e.g., from tropical to polar regions) and vertically, caus-

ing clouds, rain, and …