Question

Ben and Anne are testing if ice added to salt lowers the freezing point of water. Which experimental design would best allow them to test this?

O They get 3 cans. They add ice and salt to all 3 cans and measure the temperature at which they see frost form.
O They get 2 cans. They add ice to both cans but salt only to one can and measure the temperature at which they see frost form.
O They get 2 cans. They add ice to both cans and measure the temperature at which they see frost form.
O They get 2 cans. They add ice to both cans and salt to only one can. They place one can outside and 1 can inside. They measure the temperature at which they see frost form.

Answer 1

The best experimental design for testing if salt lowers the freezing point of water involves using two cans, adding ice to both, but only adding salt to one, and then measuring the temperature at which frost forms.

Step-by-step explanation:

Ben and Anne are testing if ice added to salt lowers the freezing point of water. The most scientifically sound experimental design to test this hypothesis would be to get two cans. In both cans, they should add ice, but only add salt to one of the cans. This allows for a control (the can without salt) and a variable (the can with salt). They should then measure the temperature at which frost forms. By having one can with only ice and another with both ice and salt, Ben and Anne can directly compare the freezing points and determine the effect of the salt This design allows them to compare the freezing points of water in the can with ice and salt to the can with just ice. If adding salt lowers the freezing point, they would expect to see frost form at a lower temperature in the can with salt. This design isolates the effect of salt on the freezing point while controlling for other variables.