What Causes the Temperature to Decrease with Height in the Troposphere? — Reading Comprehension

Grades

Standards

MS-ESS2-5

About This Reader

This NGSS-aligned middle school science passage explains why temperature decreases with height in the troposphere. Students learn that the Earth’s surface is the main source of heat, and as altitude increases, the distance from this heat source grows. The passage introduces the concept of adiabatic cooling, where rising air expands and cools due to lower air pressure. It also explains the lapse rate and how these processes lead to colder temperatures at higher elevations. Real-world examples like mountaintop temperatures and airplane altitudes support student understanding. This passage supports NGSS Earth and Atmospheric Science standards and builds key science vocabulary.

CONTENT PREVIEW

The troposphere is the lowest layer of Earth's atmosphere, where all weather happens. It extends from the ground up to about 6 to 12 miles (10 to 20 kilometers), depending on your location. One of the most important features of the troposphere is that the temperature decreases with height. But why does this happen?

The key reason is that the Earth’s surface is the main source of heat in the troposphere. The Sun warms the ground, and then the ground warms the air just above it. As you go higher up in the troposphere, you move farther from that heat source. This means the air becomes cooler the higher you go.

Another reason is air pressure. As you rise in the atmosphere, air pressure decreases. With lower pressure, rising air expands, and as it expands, it cools. This process is called adiabatic cooling. That’s why mountain tops are often much colder than valleys, even though they are the same distance from the Sun.

This decrease in temperature with altitude is known as the lapse rate. On average, the temperature drops about 6.5°C for every kilometer you go up in the troposphere.

Fun Fact: Even though airplanes fly high in the sky, they need heated cabins because outside temperatures at cruising altitudes can drop to –50°C (–58°F)!

What is the troposphere?

A layer of ocean waterThe highest part of the atmosphereThe lowest layer of the atmosphere where weather occursA part of the Earth’s core

What happens to temperature as you go higher in the troposphere?

It stays the sameIt increasesIt decreasesIt becomes hotter at night

Why does the air near Earth’s surface get warmer?

It is warmed by the cloudsThe ground absorbs sunlight and warms the airThe wind cools the surfaceRain makes the air warm

What happens to air pressure as altitude increases?

It increasesIt stays the sameIt decreasesIt freezes

What happens to rising air in the troposphere?

It condenses and heats upIt expands and coolsIt sinks and warmsIt stays at the same temperature

What is the name for the rate at which temperature drops with height?

Wind speedCloud baseLapse rateJet stream

What is the main idea of the passage?

The Sun directly heats the air at high altitudesTemperature increases with height in the troposphereTemperature decreases with height in the troposphere due to surface heating and expanding airAll parts of the atmosphere have the same temperature

Why are mountaintops colder than valleys?

Mountains are closer to spaceThe air is thicker up highThe air expands and cools as it risesSunlight skips over mountains