Question

1. Bailey wants to find out which frozen solid melts the fastest: soda, gatorade, or orange juice. She pours each of the three liquids into the empty cubes of an ice tray, along with a forth liquid, plain water. She then places the ice tray in the freezer over night. The next day, she pulls the ice tray out and sets each cube on its

own plate. She then waits and watches for them to melt. When the last part of the frozen liquid melts, she records the time.

Independent Variable:
Dependent Variable:
Control(s):
Constants:

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2. Jack wants to find out which laundry detergent cleans the best. So, he takes a cotton sheet and cuts it up into equal squares. He stains four squares with chocolate. He washes one of each of the squares in each of the 3 detergents, and the final square is washed in plain water. For each wash load, he used: the same amount of water, the same amount of detergent, and the same temperature of water.

Independent Variable:
Dependent Variable:
Control(s):
Constants:

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Maverick wants to find out whether or not Miracle Grow really makes plants grow faster. He takes two identical pots, puts ½ cup of dirt into each one, puts 3 pea plant seeds into each one, and tops each off with ½ cup more dirt. He waters the plants the same amount at the same time each day. The only difference is that one plant is watered with regular water, while the other is watered with water that has Miracle Grow in it.

Independent Variable:
Dependent Variable:
Controls(s):
Constants:

Answer 1

First situation:

IV: soda, gatorade, orange juice, and water

DV: state of IV listed above

Control: freezer, and ice tray

Second Situation:

IV: laundry detergent, water

DV: result of the squares after being washed

Control: chocolate, type of cloth, squares of cloth

Third Situation:

IV: Water used, pea plant

DV: growth of pea plant

Control: pots and amount of water plant gets each day

Answer 2

The scientific experiments are performed to test the hypothesis which comprises of three kinds of variables: independent, dependent and constant variables.

1. Independent variables: are the variables which can be manipulated that is controlled and can be changed.

2. Dependent variables: are the variables which are tested in the experiment.

3. Constant variable: the variable which is kept constant throughout the experiments but can affect the dependent variable.

4. Control: The sample which does not contain the dependent variable.

On the basis of this in the given cases the identified variables are:

Case I

Independent variables-Time and night time.

Dependent variables- melting state of liquid

Constant variable- freezer, and ice tray

Control- plain water

Case II

Independent variables- chocolate, type of cloth, squares of cloth

Dependent variables- the type of laundry detergent

Constant variable- the same amount of water, detergent and temperature.

Control- square washed with plain water.

Case III

Independent variables- Time

Dependent variables- plant growth

Constant variable- pots and an equal amount of water provided

Control- pots which were not watered by Miracle