Question

1. an automobile was tested in the lab for gas mileage. the lab test eliminated differences in wind resistance and road surface. the speeds ranged from 30 mph to 80 mph. independent variable: speed dependent variable: gas mileage controls: road surface and wind resistance 7) a bleach is tested to see what effect it has on different dye colors. the same kind of fabric is used in this experiment and is subjected to the bleach for the same amount of time. independent variable: dependent variable: controls: 8) four different antacids were tested in the lab to determine their effectiveness in neutralizing acid. the same strength and kind of acid was used. antacid was added to determine how much of each would be needed to neutralize a given quantity of the acid. independent variable: dependent variable: controls: 9) scientists hypothesized that finer grain iron oxide on video tapes would result in better recording and playback. they produced ten tapes with a range of particle sizes, recorded them, and tested the quality of the playback. human visual reaction was used to determine whether there was any significant

Explanation:

Step1: Identify independent variable for bleach - dye experiment

The factor being changed is the type of dye color, so the independent variable is dye color.

Step2: Identify dependent variable for bleach - dye experiment

The outcome being measured is the effect of bleach on the dye, so the dependent variable is the effect of bleach on dye.

Step3: Identify controls for bleach - dye experiment

The same fabric and same exposure time are kept constant, so the controls are type of fabric and exposure time to bleach.

Step4: Identify independent variable for antacid - acid experiment

The factor being changed is the type of antacid, so the independent variable is type of antacid.

Step5: Identify dependent variable for antacid - acid experiment

The outcome being measured is the amount needed to neutralize acid, so the dependent variable is amount of antacid needed to neutralize acid.

Step6: Identify controls for antacid - acid experiment

The same strength and kind of acid are kept constant, so the controls are strength and kind of acid.

Step7: Identify independent variable for iron - oxide - tape experiment

The factor being changed is the particle size of iron oxide, so the independent variable is particle size of iron oxide on video tapes.

Step8: Identify dependent variable for iron - oxide - tape experiment

The outcome being measured is the quality of playback, so the dependent variable is quality of playback.

Step9: Identify controls for iron - oxide - tape experiment

No specific controls are mentioned other than the production of ten tapes under similar conditions, but if we assume the same type of tape base etc., we can say type of tape base (assumed) could be a control.

Answer:

7)
Independent variable: dye color
Dependent variable: effect of bleach on dye
Controls: type of fabric, exposure time to bleach
8)
Independent variable: type of antacid
Dependent variable: amount of antacid needed to neutralize acid
Controls: strength and kind of acid
9)
Independent variable: particle size of iron oxide on video tapes
Dependent variable: quality of playback
Controls: type of tape base (assumed)