What does the Ozone Layer do — Reading Comprehension

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"This science reading passage explores the crucial role of the ozone layer as Earth's natural protective shield. It is designed for middle school students and aligns with NGSS standards related to Earth's systems and human impact. The passage details how the ozone layer, located in the stratosphere, absorbs harmful ultraviolet (UV) radiation from the sun, preventing it from reaching the planet's surface. It explains the natural cycle of ozone formation and destruction and highlights the significant real-world connections, such as the impact of UV radiation on human health and ecosystems. Key scientific vocabulary, including 'stratosphere' and 'UV-B radiation,' is defined and emphasized. This module provides a foundational understanding of atmospheric science and the importance of global efforts, like the Montreal Protocol, in protecting this vital component of our planet. It is an excellent resource for self-study or classroom use, helping students grasp the complex interplay between atmospheric chemistry and life on Earth."

CONTENT PREVIEW

Earth with a blue ozone layer in its atmosphere, which is deflecting and absorbing harmful purple UV radiation from the sun. — The ozone layer in the stratosphere acts as a protective shield, absorbing the sun's harmful UV radiation.

The ozone layer is a vital part of Earth's atmosphere, acting as an invisible shield that protects life from the Sun's most harmful radiation. Located within the stratosphere, this thin layer of gas is composed of ozone molecules, which each contain three oxygen atoms (O3). While ozone at ground level is a pollutant that can harm living things, ozone high in the atmosphere is essential for our planet's well-being. Without it, life on Earth would be exposed to dangerous levels of ultraviolet (UV) radiation.

The ozone layer's primary function is to absorb the Sun's high-energy UV radiation, particularly the most damaging types, UV-B and UV-C. This absorption process is a continuous cycle. When UV-C radiation strikes an oxygen molecule (O2), it splits it into two separate oxygen atoms (O). These single, highly reactive oxygen atoms then combine with other O2 molecules to form ozone (O3). This ozone molecule can then be broken apart by UV-B radiation, and the process begins again. This natural cycle effectively filters out most of the sun’s harmful UV rays before they can reach the Earth's surface.

The protective role of the ozone layer has a direct and significant impact on our daily lives. Overexposure to UV radiation can cause serious health problems in humans, including skin cancer, cataracts, and a weakened immune system. It also poses a threat to ecosystems by damaging crops and harming marine life like phytoplankton, which form the base of many oceanic food chains. Therefore, the ozone layer is not just a scientific concept; it is a critical component of the environmental system that sustains all life. Protecting it has been a global effort, as evidenced by international treaties like the Montreal Protocol, which aimed to phase out chemicals that deplete the ozone layer.

Fun Fact: The "hole" in the ozone layer isn't actually a literal hole. It's a region where the ozone concentration is significantly thinner than normal, particularly over Antarctica.

What is the primary function of the ozone layer?

To produce oxygen for us to breathe.To absorb harmful ultraviolet radiation.To regulate Earth's temperature.To create clouds for precipitation.

In which layer of the atmosphere is the ozone layer located?

TroposphereMesosphereStratosphereThermosphere

What is the chemical formula for an ozone molecule?

O2OO4O3

Which of the following is NOT a potential effect of increased UV radiation reaching Earth?

Increased rates of skin cancer.Damage to agricultural crops.A decrease in global temperatures.Harm to marine phytoplankton.

What does the passage suggest about ozone at ground level?

It is the same as the ozone in the stratosphere.It is a harmful air pollutant.It helps to protect against UV radiation.It is a harmless, natural gas.

The natural cycle of ozone formation and destruction is most similar to which of the following processes?

A light switch being turned on and off.A car engine consuming gasoline.A dam regulating the flow of a river.A plant absorbing sunlight for photosynthesis.

Which of the following best summarizes the main idea of the passage?

The ozone layer is a complex part of the atmosphere.Humans are the sole cause of ozone layer thinning.The ozone layer is an essential shield that protects life from UV radiation.The Montreal Protocol successfully fixed all environmental issues.

If the ozone layer were to completely disappear, what would be the most immediate consequence for humans?

Global sea levels would rise.The climate would become much colder.The risk of skin cancer would increase significantly.It would be impossible to grow any food crops.