Feedback loops: changes that grow or shrink themselves
Grade 9 Science Worksheet
Circle the best answer.
“Loop diagram:” Warming thaws permafrost. The thawed soil releases carbon dioxide and methane, which warm the air more (NASA). What kind of loop is this, by Bo's reading?
- Not a feedback; the gases are the starting forcing
- Negative, since the gases are harmful
- Positive: it amplifies the warming
- Negative: the thawing uses up the warming
More carbon dioxide helps many plants grow more, and the extra growth takes some carbon dioxide back out of the air (NASA). What kind of loop is this, by Esme's reading?
- Negative: it removes the added carbon dioxide completely
- Positive, since it is good for plants
- Positive: carbon dioxide and plants both increase
- Negative: it shrinks part of the rise
Warmer air holds more water vapor, a greenhouse gas, which warms the air further. NASA estimates this more than doubles the warming from carbon dioxide alone. What kind of loop, by Jun's reading?
- Negative, since more vapor is a bad thing
- Not a feedback; water vapor is the original cause
- Negative: the extra vapor cancels the warming
- Positive: it more than doubles the warming
“Loop diagram:” The ice-albedo loop has these links: temperature → sea ice (−); sea ice → sunlight absorbed (−); sunlight absorbed → temperature (+). What is the loop's sign, by Kira's count?
- Negative, since melting ice is bad
- Positive, but just because one link is +
- Negative, since it has − links in it
- Positive: two − links make the loop +
A home heating loop: room temperature → thermostat calls for heat (−); call for heat → furnace output (+); furnace output → room temperature (+). What is its sign, by Milo's count?
- Negative: one − link makes the loop −
- Negative, so the room ends up colder than the setting
- Positive, since a warm home is good
- Positive: two + links outnumber one −
Sunlight of 200 W/m² falls on sea ice with an albedo of 0.6. How much does the ice absorb, by Noah's math?
- 0.4 W/m²
- 120 W/m², the reflected part
- 200 W/m²
- 80 W/m²
That patch of sea ice (albedo 0.6) melts into open ocean (albedo 0.06) under the same 200 W/m². How does the energy it absorbs change, by Ren's math?
- 108 W/m² more is absorbed
- It absorbs the same amount
- 108 W/m² less is absorbed
- 268 W/m² more is absorbed
Read this first
Arctic in late summer (model data)
Year Sea ice (million km²) Air temperature change (°C) 1985 7.5 0.0 2005 5.9 0.9 2025 3.8 2.1 Which statement do the Arctic data support, by Tala's reading?
- Less ice went along with warmer Arctic air
- More ice went along with warmer air
- The ice loss was the starting forcing in 1985
- The data show a negative loop
Yearly carbon dioxide (model data)
Flow Units per year added by people 10 taken up by extra plant growth 3 People add 10 units of carbon dioxide a year; extra plant growth takes up 3 units. How does the plant loop change the yearly rise, by Zee's math?
- It does not change the rise
- From 10 to 7 units, about 30% smaller
- From 10 to 13 units
- From 10 to 0 units; the rise stops
Warming and water vapor (model data)
Warming (°C) Water vapor change (%) 1 7 2 14 3 21 Which pattern in the table supports a positive water-vapor loop, by Ari's reading?
- Vapor rises with warming, so the loop is negative
- Vapor rises with warming, adding more warming
- Vapor falls as the air warms
- Vapor rises, showing vapor started the warming