Question

chemistry i experimental design hw
name: shaudee benner hr. 3rd
independent variable:
dependent variable(s):
constants:
control:
sue was a chemistry student who liked to cook. one day she noticed that her mom put salt into the water before she boiled it to make noodles. she asked her mom if that was just for taste. sues mom said that taste was one reason but she also said it made the pasta cook faster. sue figured that salt must make the water boil faster so the food cooks quicker.
she wanted to see if she was right so she asked her chemistry instructor if she could perform a little experiment. sue put 100ml of water into three 150ml beakers. the first beaker she left as plain water; in the second she put 5g of salt; and in the third she put 10g of salt. she set each at the same height above bunsen burners on the same setting and measured the amount of time it took for the water to boil. to her surprise, she found that the sample with no salt actually boiled soonest, while the beaker with the most salt took the longest.
sue realized there must be something else going on. she wondered if salt actually made the water boil at a higher temperature; which would explain why it would take longer to boil and also might explain why it cooks the food faster. she performed the same experiment as before except this time she measured the temperature of the water when it began to boil instead of the amount of time. sue found that the first sample boiled at 100°c, the beaker with 5g of salt boiled at 102°c, and the sample with 10g of salt boiled at 105°c. her results for both experiments are below...
experiment #1

sample	amount of salt / 100ml water	time to boil (min:sec)
2	5g	6:02
3	10g	6:56

experiment #2

sample	amount of salt / 100ml water	boiling temp (°c)
2	5g	102°c
3	10g	105°c

Explanation:

Step1: Identify variables

Independent variable is the amount of salt added to 100mL of water (none, 5g, 10g). Dependent variables are the time to boil and the boiling - temperature of water. Constants are the volume of water (100mL), height above Bunsen burners, Bunsen burner setting. The control is the beaker with plain water (no salt).

Answer:

Independent Variable: Amount of salt added to 100mL of water (0g, 5g, 10g)
Dependent Variable(s): Time to boil, Boiling temperature of water
Constants: Volume of water (100mL), height above Bunsen burners, Bunsen burner setting
Control: Beaker with plain water (no salt)