Al wonders if adding salt to water will affect how long it takes the water to freeze. Al thinks that
salt water will freeze more quickly than fresh water. He decides to check his hypothesis by
conducting an experiment. Al takes two ice trays and fills one with distilled water and the other
with distilled water that has two tablespoons of salt added. He makes sure he puts exactly the
same amount of water in each ice tray. Al takes the trays and puts them side by side in the
freezer. Al checks the ice trays every 10 minutes to see if the water in each tray has begun to
freeze. Al finds that after 20 minutes the water in the ice tray without the salt has started to form
ice, while the ice tray with the salt water is still completely liquid. What would be the independent, dependent and control variable for the experiment