I am embarking on a project in which I hope to demonstrate that salt makes ice melt. The experiment would involve exposing ice to different concentrations of salt and measuring the melting rate. How can I best express my hypothesis for such an experiment?
Anyone who lives in a section of the country where highways freeze probably knows that salt is sometimes sprinkled on the roadways to promote melting of the ice. From this knowledge, or other observations, or perhaps through reasoning such as that included in the reference, one might come up with the hypothesis that salt promotes melting of ice.
Your hypothesis should be stated clearly and briefly such as the following:
Hypothesis: Exposure of ice to salt will increase the speed at which the ice melts.
You would then outline your experiment, perhaps in a fashion similar to the following.
Method: Ice cubes freshly removed from the freezer will be placed in several glasses of salted water, all of which are at room temperature. The salt concentration in each glass will be recorded. Two ice cubes will be placed in each glass simultaneously. The glasses will be recorded by a video camera such that the time at which the ice cubes in each glass disappear can be measured. The results will be expressed as melting times plotted against salt concentration. In this manner the hypothesis will be tested.
Please see the reference for a good description and tutorial on the scientific basis underlying the fact that salt does indeed speed up the rate at which ice melts.
You have to conduct an experiment to test how the concentration of salt affects the rate of melting in ice cubes. For this you can write an if-then statement about what you are doing.
Now you already know that salt makes ice melt, so this would not be a good hypothesis that we can derive from the first statement.
A better way is to write it as: If more salt is added on ice cubes to increase the concentration of salt, then the ice cubes melt at a faster rate.
Here "more salt is added on ice cubes to increase the concentration of salt" is the hypothesis and "the ice cubes melt at a faster rate" is the conclusion.