Scenario+3

Al's Salt Water Experiment

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 tray__s 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 tray__ __after 20 minutes the water in the__ __ice wit__ __hout the salt has started to form ice while the ice tray with the salt water is completely liquid.__

Complete each of the following:
 * 1) Identify Al's hypothesis: Salt water will freeze more quickly than fresh water.
 * 2) Identify the independent variable: The saltwater.
 * 3) Identify the dependent variable: The quickness of the saltwater and fresh water freezing.
 * 4) Identify the other variables Al needs to consider/control during this experiment: The temperature of freezer, amount of water, amount of salt added to the water, the kind of salt,how much power the freezer has, the kind of freezer, how big the ice trays are, how much water there is, how many spaces the ice trays have, how warm the water is at first, the kind of water (bottled/tap), how long the water has been sitting out.
 * 5) Identify the control group in this experiment: The fresh water without any salt.
 * 6) Identify the experimental group: The water with salt in it or the saltwater.
 * 7) What conclusions might Al draw from this data? That freshwater freezes before satwater, also the more salt in water the longer it takes to freeze in cold temperatures.
 * 8) What recommendations might you suggest for further study or for improvement? Add less salt, check both of the water's temperature, get a repair technician to check the freezer to see if the freezer is working correctly, make the temperature in the freezer colder, get a stopwatch to check every ten minutes, get different kinds of ice trays.