Positive and Negative Feedback

In some developing countries poverty causes illness and contributes to poor standards of education. In the absence of knowledge of family planning methods and hygiene, this contributes to population growth and illness, adding further to the causes of poverty; “a vicious circle of poverty.”

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Tags

NGSS.MS-ESS3-4

NGSS.MS-LS2-4

A thermostat in a central heating system can determine the temperature of your living room. It switches the air conditioner on when the temperature increases to a predetermined level and shuts it off when it cools to another level. The room temperature remains within a comfortable level regardless of the temperature outside

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Tags

NGSS.HS-LS1-3

Some organisms have internal feedback systems. Physiological changes occur to prevent breeding when population densities are high and promote breeding when population densities are low.

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Tags

NGSS.HS-LS1-3

You are lost on a snowy mountain. When your body senses that it is cooling below 37°C, various mechanisms such as shivering help to raise your body core temperature again. However if these are insufficient to restore normal body temperature, our metabolic processes start to slow down, because the enzymes that control them do not work so well at lower temperatures. As a result, you become lethargic and sleepy and move around less and less, allowing your body to cool even further. Unless you are rescued at this point, your body will reach a new equilibrium; you will die of hypothermia.

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Tags

NGSS.HS-LS1-3

As carbon dioxide levels in the atmosphere rise, the temperature of the Earth rises. As the Earth warms the rate of photosynthesis in plants increases, more carbon dioxide is therefore removed from the atmosphere by plants, reducing the greenhouse effect and reducing global temperatures.

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Tags

NGSS.HS-ESS2-2

NGSS.HS-LS2-5

As the Earth warms, increased evaporation produces more clouds. Clouds increase albedo, reflecting more light away from the Earth. The temperature falls. Rates of evaporation fall

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Tags

NGSS.HS-ESS2-2

NGSS.HS-ESS2-4

NGSS.HS-ESS3-5

As the Earth warms, evaporation increases. Snowfall at high latitudes increases, icecaps enlarge. More energy is reflected by increased albedo of ice cover. The Earth cools. Rates of evaporation fall.

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Tags

NGSS.HS-ESS2-2

As the Earth warms, polar icecaps melt, releasing large numbers of icebergs into oceans. Warm ocean currents such as the Gulf Stream are disrupted by additional freshwater input into oceans. Reduced transfer of energy to the poles reduces temperature at high altitudes. Ice sheets reform and icebergs retreat. Warm currents are re-established.

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Tags

NGSS.HS-ESS2-2

NGSS.HS-ESS2-4

In a biological system, when a hormone is released to increase blood sugar levels, and this triggers the release of another hormone to decrease blood sugar levels, what type of feedback is this?

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Tags

NGSS.HS-LS1-3

In climate science, when the melting of polar ice reduces the Earth's albedo, leading to further warming and more ice melting, what type of feedback is this?

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Tags

NGSS.HS-ESS2-2