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ACID RAIN SCORING 2

Full Credit

Code 2:

Any one of car exhausts, factory emissions, burning fossil fuels such as oil and coal, gases from volcanoes or other similar things.

• Burning coal and gas.

• Oxides in the air come from pollution from factories and industries.

• Volcanoes.

• Fumes from power plants. [«Power plants» is taken to include power plants that burn fossil fuels.]
• They come from the burning of materials that contain sulfur and nitrogen.

Partial Credit

Code 1:

Responses that include an incorrect as well as a correct source of the pollution.

• Fossil fuel and nuclear power plants. [Nuclear power plants are not a source of acid rain.]

• The oxides come from the ozone, atmosphere and meteors coming toward Earth. Also the burning of fossil fuels.

Responses that refer to «pollution» but do not give a source of pollution that is a significant cause of acid rain.

• Pollution.

• The environment in general, the atmosphere we live in – e.g., pollution.

• Gasification, pollution, fires, cigarettes. [It is not clear what is meant by «gasification»; «fires» is not specific enough; cigarette smoke is not a significant cause of acid rain.]

• Pollution such as from nuclear power plants.

Scoring Comment: Just mentioning «pollution» is sufficient for Code 1. Any accompanying examples are only assessed to see if the response merits Code 2 instead.


No Credit

Code 0:

Other responses, including responses that do not mention «pollution» and do not give a significant cause of acid rain.

• They are emitted from plastics.

• They are natural components of air.

• Cigarettes.

• Coal and oil. [Not specific enough – no reference to «burning».]

• Nuclear power plants.

• Industrial waste. [Not specific enough.]

Code 9:

Missing.

ACID RAIN SCORING 5

Full Credit

Code 2:

To compare with the test of vinegar and marble and so show that the acid (vinegar) is necessary for the reaction.

• To make sure that rainwater must be acidic like acid rain to cause this reaction.

• To see whether there are other reasons for the holes in the marble chips.

• Because it shows that the marble chips don’t just react with any fluid since water is neutral.

Partial Credit
Code 1:

To compare with the test of vinegar and marble, but it is not made clear that this is being done to show that the acid (vinegar) is necessary for the reaction.

• To compare with the other test tube.

• To see whether the marble chip changes in pure water.

• The students included this step to show what happens when it rains normally on the marble.

• Because distilled water is not acid.

• To act as a control.

• To see the difference between normal water and acidic water (vinegar).


No Credit
Code 0:

Other responses.

• To show the distilled water wasn’t an acid.

Code 9:

Missing.


SUNSCREENS SCORING 5


Full Credit

Code 2:

A. With explanation that the ZnO spot has stayed dark grey (because it blocks sunlight) and the M spot has gone white (because mineral oil absorbs very little sunlight).

[It is not necessary (though it is sufficient) to include the further explanations that are shown in parentheses.]
• A. ZnO has blocked the sunlight as it should and M has let it through.

• I chose A because the mineral oil needs to be the lightest shade while the zinc oxide is the darkest.

Partial Credit

Code 1:

A. Gives a correct explanation for either the ZnO spot or the M spot, but not both, and does not give an incorrect explanation for the other spot.

• A. Mineral oil provides the lowest resistance against UVL. So with other substances the paper would not be white.

• A. Zinc oxide absorbs practically all rays and the diagram shows this.


No Credit

Code 0:

Other responses.

• A because ZnO blocks the light and M absorbs it.

• B. ZnO blocks the sunlight and mineral oil lets it through.

Code 9:

Missing.