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Behavior of Gases — Reading Comprehension

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MS-PS1-4

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This comprehensive reading passage explores the behavior of gases for middle school students, aligned with NGSS standard MS-PS1-4. Students will learn about key properties such as compressibility, the ability of gases to expand and fill any container, and how gases exert pressure. The passage explains the relationships among temperature, volume, and pressure through conceptual explanations and real-life examples like balloons expanding in heat, tire pressure changes, and how syringes work. Academic vocabulary is embedded and clarified within the text, and students are provided with a glossary for reference. The lesson includes a simplified version of the passage for differentiated instruction, a Spanish translation, multiple-choice and writing activities, and graphic organizers to support comprehension. Audio integration is available for accessibility. This resource is ideal for deepening students’ understanding of gas behavior and supporting science literacy in grades 6-8.

CONTENT PREVIEW

Kinetic-Molecular-Theory-3 — Visualizing the gas laws

Gases are a state of matter that are all around us, playing crucial roles in both natural and engineered systems. The air we breathe, the helium in balloons, and the oxygen tanks used in hospitals are all examples of gases that behave in special ways. Unlike solids and liquids, gases do not have a fixed shape or volume. Instead, they completely fill whatever container they are in, no matter the size or shape. Understanding how gases behave helps scientists and engineers solve problems in fields ranging from medicine to transportation.

How Gases Behave: Mechanisms and Properties

One of the most important properties of gases is their compressibility. This means that gases can be squeezed into a smaller volume by applying pressure. When a gas is compressed, its particles move closer together, but they still move freely and rapidly. For example, when you push the plunger of a syringe, you decrease the space inside, compressing the air and increasing its pressure. The ability to compress gases is used in many technologies, such as pumps and air tanks.

Gases also expand to fill any available space. This is called expansion. If you heat a balloon, the gas particles inside gain energy and move faster, causing the balloon to grow larger. This expansion shows the relationship between temperature and volume: as temperature increases, so does the volume, if pressure remains constant. This is why hot air balloons rise—the heated air inside expands, becoming less dense than the cooler air outside.

Interactions: Temperature, Volume, and Pressure

The behavior of gases is governed by the interactions among temperature, volume, and pressure. When temperature rises, gas particles move faster and collide with the walls of their container more often and with greater force. This increases the pressure if the volume is kept the same. Conversely, if you increase the volume of the container while keeping temperature steady, the pressure decreases because the particles have more space to move. This relationship can be observed in real life: on a hot day, the pressure inside a car tire goes up because the air molecules are moving faster. If a tire is punctured, the volume available for the gas increases and the pressure drops quickly.

These interactions also explain why syringes work. When you pull back the plunger, you increase the volume inside the barrel, so the air pressure drops and liquid is drawn in. When you push the plunger, the volume decreases, the pressure rises, and the liquid is pushed out. Understanding these principles allows people to design safe and effective medical equipment, air pumps, and even scuba diving tanks.

Applications and Broader Connections

The unique properties of gases are essential in many areas of technology and daily life. For example, the compressibility of gases makes it possible to transport oxygen in small tanks for hospitals or to run pneumatic tools in construction. The expansion of gases is used in engines and airbags, and the ability of gases to exert pressure is critical in weather forecasting. Meteorologists study changes in air pressure to predict storms and clear skies. These same principles are part of the larger scientific idea that matter is made of particles whose motion and interactions determine the properties of substances.

By studying the behavior of gases, scientists have developed models that help us understand everything from climate patterns to how our bodies function. The relationships among temperature, volume, and pressure are fundamental to chemistry and physics, and they shape the world we experience every day.

Interesting Fact:
Earth’s atmosphere is made up of about 78% nitrogen gas, 21% oxygen gas, and only around 1% other gases, yet these small differences make a huge impact on life and weather!

What property allows gases to be squeezed into a smaller space?

CompressibilityDensityExpansionTemperature

Which of the following is an example of gas expansion in real life?

A balloon growing larger in the sunA rock sinking in waterSugar dissolving in teaA book falling off a table

What happens to gas particles when the temperature increases?

They move fasterThey stop movingThey become largerThey freeze

In the passage, what is the main function of a syringe related to gases?

It changes the volume and pressure of the gas insideIt measures the temperature of the gasIt cools the gas insideIt separates gases into different types

What does the word "compressibility" mean as used in the passage?

The ability to be squeezed into a smaller volumeThe ability to expand without limitThe ability to transfer heat quicklyThe ability to float in water

What does the word "pressure" mean in the context of gases?

The force gases exert on their containerThe color of a gasThe temperature of a gasThe speed of wind

Why does tire pressure increase on a hot day, according to the passage?

Because gas particles move faster and hit the tire walls with more forceBecause the tire shrinks in sizeBecause air escapes from the tireBecause the tire is made of metal

If you pull back the plunger of a syringe, what happens to the pressure inside?

It decreasesIt increasesIt stays the sameIt disappears

True or False: Gases have a fixed shape and volume.

TrueFalse

True or False: The Earth's atmosphere is made up of mostly nitrogen and oxygen gases.

TrueFalse