SCIENCE
PHYSICAL SCIENCES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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amount of water
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amount of salt in water
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temperature at which water freezes
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all of these
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Detailed explanation-1: -We are told that the amount of salt will be kept at a constant value and as such the amount of salt is a controlled variable. Similarly, the amount of water present (100 mL) will also be kept constant making it a controlled variable.
Detailed explanation-2: -Hypothesis: The more salt added into the water, the density of the water will be increased because salt weighs more than water. Therefore, the water will have a lower freezing point. Independent: the difference in each cup is the amount of salt added to the water.
Detailed explanation-3: -VARIABLES: The independent variable is the different amounts salt that will be added to the water (what is done by the scientist). The dependent variable is the boiling temperature of the water (what is being measured).
Detailed explanation-4: -Fresh water freezes at 32 degrees Fahrenheit but seawater freezes at about 28.4 degrees Fahrenheit, because of the salt in it. When seawater freezes, however, the ice contains very little salt because only the water part freezes. It can be melted down to use as drinking water.