Bellwork March 1 2007 Define the following words

Bellwork March 1, 2007 • Define the following words: Page 434 – Atmosphere – Troposphere – Ionosphere – Ultraviolet Radiation (U. V. Radiation) – Ozone Layer – Chlorofluorocarbon (CFC’s)

Chapter 15: Earth’s Atmosphere

What is the Atmosphere? • The atmosphere surrounds Earth and protects • • us by blocking out dangerous rays from the sun. Is a mixture of gases that is layered and becomes thinner until it gradually reaches space. Insulates the Earth.

Composition of Earth’s Atmosphere • • • 78% Nitrogen 21% Oxygen ~3% Water Vapor 0. 93% Argon 0. 04% Carbon Dioxide trace amounts of other gases

Layers of the Atmosphere • Divided into five • • different and distinct layers. Lower layers include the troposphere and stratosphere Upper layers are the mesosphere, thermosphere and exosphere. Page 436

Lower Layers • Troposphere • Stratosphere

Troposphere • Where we study, eat, • • • sleep, and play. Lowest of Earth’s atmospheric layers. Contains 99% of the water vapor and 75% of atmospheric gases. Layer in which clouds and weather occur.

Stratosphere • ~ 10 km (6 mi) to 50 km • • (30 mi) above Earth’s Surface Contains Ozone (O 3) Layer Temperature increases with altitude.

Upper Layers • Mesosphere • Thermosphere • Exosphere Page 437

Mesosphere • From Stratosphere to 80 • • km (50 mi) above surface. Temperature decreases with altitude. Layer in which most meteors will burn up.

Ionosphere • Layer of electrically • • charged particles. Contained within the mesosphere and thermosphere. Allows radio waves to travel across the country. Pg 437

Thermosphere • Extends to from • • mesosphere to 500 km Contains the Auroras Thickest of the layers Temperature varies greatly based on solar energy. Can heat up to 1, 500°C or higher

Exosphere • Outermost layer • • extending to 800 km. Where satellites and shuttles orbit the Earth. Contains very few molecules

Ozone Layer • Contained within the stratosphere. • It helps to protect us from the sun’s rays. • Located 19 -48 km above us. • Made of ozone (O ). • Destroyed by CFC’s. • Hole in the ozone layer is increasing each year. • When the ozone layer disappears there will be 3 more cases of skin cancer. Student’s Created

Assignment • Draw the layers of the atmosphere. • Label each layer with the following: – Name – Range (distance from Earth’s Surface) – Characteristics – Temperature Range (Page 439)