4.4 Earth's Atmosphere

Question 1

Denitrification

Answer 1

Denitrification is the process by which certain bacteria convert nitrates (NO3-) back into nitrogen gas (N2), completing the nitrogen cycle. This process occurs in oxygen-depleted environments, such as wetlands or waterlogged soils.

Think of denitrification as a “nitrogen escape room.” Just like how people work together to find clues and escape from a locked room, bacteria team up to convert nitrates back into nitrogen gas, freeing it from the cycle.

Question 2

Nitrogen Cycle

Answer 2

The nitrogen cycle refers to the continuous movement of nitrogen between living organisms, the atmosphere, and the environment. It involves various processes such as nitrogen fixation, nitrification, assimilation, ammonification, and denitrification.

Imagine the nitrogen cycle as a giant recycling system for nutrients. Just like how you recycle paper or plastic bottles to be reused again and again, nature recycles nitrogen through different stages to ensure its availability for plants and animals.

Question 3

Photosynthesis

Answer 3

Photosynthesis is the process by which green plants, algae, and some bacteria convert sunlight, carbon dioxide, and water into glucose (a form of sugar) and oxygen. It occurs in chloroplasts within plant cells.

Think of photosynthesis as a solar-powered factory inside plant cells. Just like how a factory uses raw materials to produce goods with the help of machinery, plant cells use sunlight, carbon dioxide, and water to create glucose using specialized structures called chloroplasts.

Question 4

Troposphere

Answer 4

The troposphere starts at ground level and goes up to around 10 kilometers in altitude, about the average height of a cruising airplane. This layer is the shallowest layer of the atmosphere. Within this layer, temperature decreases as altitude increases, as all weather occurs in this atmospheric layer.

Question 5

Mesosphere

Answer 5

The mesosphere goes from 50 kilometers to 80 kilometers in altitude. In this layer, the temperature decreases as you increase in altitude. This layer is very cold, and temperatures in the mesosphere can reach below -80 °C (-115 °F).

Question 6

Thermosphere

Answer 6

The Thermosphere goes from about 80 kilometers to 100 kilometers in altitude. Another name for the thermosphere is the ionosphere because this layer often traps protons, electrons, and other ions given off by the sun. As you increase in altitude in this layer, the temperature increases because this layer receives a lot of UV radiation and energy from the sun.