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What is the Coldest Layer of the Atmosphere — Reading Comprehension

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"This NGSS-aligned passage is designed for middle school students (grades 6-8) to introduce them to the mesosphere, the coldest layer of Earth's atmosphere. The content addresses key Earth science concepts, including the structure of the atmosphere and the protective role it plays. Students will learn about the mesosphere's unique temperature profile, the reasons behind its extreme cold, and its crucial function in incinerating meteors. The passage includes key scientific vocabulary and real-world connections to make the topic engaging and relevant. It provides a solid foundation for understanding atmospheric science, fulfilling objectives related to NGSS standards like MS-ESS2-1, which focuses on developing a model to describe the cycling of Earth's materials and the flow of energy that drives these processes."

CONTENT PREVIEW

the layers of Earth's atmosphere, with the mesosphere highlighted and meteors shown burning up within it. — The mesosphere, the coldest layer of the atmosphere, where most meteors burn up.

Earth's atmosphere is a blanket of gases that surrounds our planet, divided into five main layers. Each layer plays a unique role, but one stands out for its extreme temperature: the mesosphere. This layer sits above the stratosphere and below the thermosphere, stretching from about 50 kilometers (31 miles) to 85 kilometers (53 miles) above the Earth's surface. It is within the mesosphere that the coldest temperatures in the entire atmosphere are found, dropping as low as -90°C (-130°F).

The mesosphere's frigid temperatures are a result of its unique composition and position. Unlike the layers below it, the mesosphere contains very little water vapor and ozone. These gases absorb solar radiation and help to warm other atmospheric layers. Without them, the mesosphere's thin air has few molecules to absorb heat from the sun, causing the temperature to plummet with increasing altitude. This lack of heat absorption is the primary reason for its intense cold.

The most exciting and well-known feature of the mesosphere is its role as Earth's natural shield against space debris. Most meteors—rocky or metallic objects from space—that enter the atmosphere will burn up due to friction with the air molecules in this layer. The intense heat generated by this friction causes them to vaporize, creating the bright streaks of light we see from the ground, commonly known as "shooting stars." This protective function prevents countless meteors from reaching the surface and causing harm.

In essence, the mesosphere serves as a crucial transition zone. It marks the boundary where the air becomes too thin to breathe but is still dense enough to incinerate incoming space rocks. It is a critical, yet often overlooked, layer that helps to maintain the safety and stability of our planet.

Fun Fact: Scientists know very little about the mesosphere because it is too high for weather balloons and too low for orbiting satellites to study effectively. This makes it one of the least understood regions of our atmosphere.

What is the coldest layer of Earth's atmosphere?

The troposphereThe stratosphereThe mesosphereThe thermosphere

What is the approximate altitude range of the mesosphere?

0 to 15 kilometers15 to 50 kilometers50 to 85 kilometers85 to 600 kilometers

What is the primary reason the mesosphere is so cold?

It is the furthest layer from the sun.It contains a lot of water vapor.It has very few molecules to absorb solar radiation.It is warmed by the layer above it.

Which of the following best describes the main idea of the reading passage?

Earth's atmosphere has five layers.The mesosphere is the coldest atmospheric layer and protects Earth from meteors.The thermosphere is the hottest layer of the atmosphere.Scientists know everything about the mesosphere.

A small piece of a comet, known as a meteoroid, is on a path to collide with Earth. In which layer of the atmosphere would it most likely begin to burn up?

The troposphereThe stratosphereThe thermosphereThe mesosphere

What happens to most meteors when they enter the mesosphere?

They speed up and pass through to the next layer.They are absorbed by the atmosphere and become part of the air.They begin to burn up due to friction.They cool down due to the low temperature.

Based on the passage, what is a key difference between the mesosphere and the layers below it?

The mesosphere has a higher concentration of ozone.The mesosphere contains more water vapor.The mesosphere has fewer gases that absorb solar radiation.The mesosphere is the only layer where temperatures drop.

Which scientific term is used to describe the rocky or metallic objects from space that burn up in the mesosphere?

MeteorsAsteroidsCometsPlanets