Feedback loops: changes that grow or shrink themselves
Grade 9 Science Worksheet
Circle the best answer.
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?
- Positive, since it is good for plants
- Negative: it shrinks part of the rise
- Negative: it removes the added carbon dioxide completely
- Positive: carbon dioxide and plants both increase
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: the extra vapor cancels the warming
- Positive: it more than doubles the warming
- Negative, since more vapor is a bad thing
- Not a feedback; water vapor is the original cause
“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 it has − links in it
- Positive, but just because one link is +
- Positive: two − links make the loop +
- Negative, since melting ice is bad
The plant loop has two links: carbon dioxide → plant growth (+); plant growth → carbon dioxide (−). What is the loop's sign, by Luz's count?
- Negative, so carbon dioxide returns to its old level
- Negative: one − link makes the loop −
- Positive, since it has a + link
- Positive, since plant growth is good
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?
- Positive, since a warm home is good
- Positive: two + links outnumber one −
- Negative, so the room ends up colder than the setting
- Negative: one − link makes the loop −
The same 200 W/m² falls on open ocean with an albedo of 0.06. How much does the ocean absorb, by Pia's math?
- 188 W/m²
- 12 W/m², the reflected part
- 194 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 less is absorbed
- 108 W/m² more is absorbed
- 268 W/m² more is absorbed
- It absorbs the same amount
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?
- More ice went along with warmer air
- The data show a negative loop
- The ice loss was the starting forcing in 1985
- Less ice went along with warmer Arctic air
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?
- From 10 to 13 units
- From 10 to 0 units; the rise stops
- From 10 to 7 units, about 30% smaller
- It does not change the rise
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, showing vapor started the warming
- Vapor rises with warming, so the loop is negative
- Vapor rises with warming, adding more warming
- Vapor falls as the air warms