QUESTIONS Lessons 4-5

Question 1

Open vs. Closed system (with examples)

Answer 1

An open system is where energy and matter can leave. ex. hot cup of coffee, stove
A closed system is where energy can leave but matter cannot. ex. thermos of coffee, boiling water in a closed pot

Question 2

Positive vs Negative feedback loops (with examples)

Answer 2

Positive = speeds up warming
ex. As ice and snow melt in polar regions, the Earth’s surface becomes darker/ having lower albedo, leading to increased warming and further ice melt.

Negative = slows down warming
ex. As temperatures rise, increased evaporation can lead to more cloud formation. Clouds reflect sunlight back into space, which can have a cooling effect on the Earth’s surface.

Question 3

How thermal energy from the sun is transferred through radiation, conduction, and convection

Answer 3

Radiation: Short waves of radiation heat the ground while long waves heat the air.

Conduction: Molecules collide from the ground and air, transferring energy and heating the air.

Convection: Cool air from the atmosphere goes down and warm air from the ground goes up

Question 4

How wind, heat, and salinity contribute to thermohaline circulation, and how global warming disrupts this circulation pattern

Answer 4

Changes in temperatures and salinity (amount of salt dissolved in the water) affect thermohaline circulation.

As Earth’s climate warms, the water also warms melting sea ice. This warming could make the water less cold and less likely to sink. Without sinking cold water, the ocean currents could slow down or stop in some places.

Question 5

How reflection and absorption of solar radiation keeps Earth’s energy budget balanced, and how global warming disrupts this budget.

Answer 5

The energy that Earth receives from sunlight is balanced by an equal amount of energy radiating into space. Global warming causes more energy to be received by Earth than received back into space (greenhouse effect)

Question 6

Sources and sinks of greenhouse gases
(methane, nitrous oxide, ozone)

Answer 6

Methane -
Sources:
Natural: From melting permafrost (positive feedback)
Human: Livestock, fossil fuels
Sink: Atmosphere for about 12 years

Nitrous oxide -
Sources:
Natural: bacteria
Human: Chemical fertilizers, vehicle exhaust
Sink: Destroyed naturally by sunlight (takes about 115 years in the atmosphere…)

Ozone -
Sources:
Naturally in the stratosphere & makes up the ozone layer which blocks UV radiation
Ground-level ozone forms smog from car exhaust
Sink: None

Question 7

Ways to reduce the effects of greenhouse gases

Answer 7

Use less electricity.
Generate electricity without emissions.
Shrink the footprint of food. Travel without making greenhouse gases.
Reduce household waste