Grady is doing an experiment about the solubility of sugar. He puts 100 milliliters of water in each of three beakers. He leaves the
first beaker at room temperature, heats the second beaker to 60°C, and heats the third beaker until the water boils at 100°C.
To the first beaker, he adds sugar, one spoonful at a time, until not all of the sugar can dissolve when he stirs it. He records the
number spoonfuls that dissolved. Then he repeats the same process of adding sugar and stirring for the beakers of hot water and
boiling water.
What variable does Grady change on purpose in the investigation?
A. the volume of water in each beaker
B. the amount of sugar added to each beaker
c. the size of each of the beakers
D. the temperature of the water in each beaker