Question

1. you decide to clean the bathroom. you notice that the shower is covered in a strange green slime. you try to get rid of this slime by adding lemonade juice. you spray half of the shower with lemonade juice and spray the other half of the shower with water. after 3 days of spraying equal amounts 3 times a day, there is no change in the appearance of the green slime on either side of the shower.

iv
dv
cg

1. you decide to clean your bedroom. you notice that your floor is covered with clothes. you try to get rid of the clothes by throwing them into the air. you throw clothes from 1/3 of the room into the closet and a second 1/3 of the room straight up in the air. the last 1/3 of the room you leave the clothes on the floor. after 30 minutes of “cleaning,” the floor of the room is now visible.

iv
dv
cg

1. you want to test which size of soccer (football) ball is easiest to juggle with your feet. you test a size 3, size 4 and a size 5 ball. you count the seconds the ball stays in the air for each of the trials. you allow yourself to use both of your feet, knees, and head to juggle the ball.

iv
dv
c
© ngss life science 2015

Explanation:

Step1: Identify IV, DV and CG for first experiment

The independent variable (IV) is what is being changed. Here, it's the liquid sprayed (lemonade juice or water). The dependent variable (DV) is what is being measured, which is the appearance of the green - slime. The control group (CG) is the group with no treatment change, so the side sprayed with water is the control group.

Step2: Identify IV, DV and CG for second experiment

The IV is what is done with the clothes (thrown into closet, thrown in air, left on floor). The DV is whether the floor is visible or not. There is no traditional control group as all parts of the room are being manipulated in some way, but the part with clothes left on the floor can be considered a baseline for comparison.

Step3: Identify IV, DV and C for third experiment

The IV is the size of the soccer ball (size 3, size 4, size 5). The DV is the number of seconds the ball stays in the air. There is no control group in the traditional sense, but the general juggling conditions (using feet, knees, head) are kept constant.

Answer:

1. IV: Liquid sprayed (lemonade juice or water)

DV: Appearance of green slime
CG: Shower side sprayed with water

1. IV: What is done with the clothes (thrown into closet, thrown in air, left on floor)

DV: Visibility of the floor
CG: Clothes left on the floor

1. IV: Size of the soccer ball (size 3, size 4, size 5)

DV: Number of seconds the ball stays in the air
C: None (but juggling conditions are constant)