Question

experimental variables worksheet
directions: determine the independent variables (iv), dependent variables (dv), constants, and controls from the following science experiments.

• independent variable (iv): what the experimenter changes during the experiment.
• dependent variable (dv): what the experimenter measures.
• constants: things that are kept the same.
• control: thing to compare against to see if independent variable has any affect.

1. the number of flowers on different breeds of bushes in a greenhouse is recorded every week for two months.

iv:
dv:
constants:
control:

1. you give four sunflowers different watering with either pure water or different concentrations of salt solutions. after a two - week period, the height is measured.

iv:
dv:
constants:
control:

1. three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. one tree is left outside in normal conditions. height of the tree is measured once a week.

iv:
dv:
constants:
control:

Explanation:

Step1: Identify variables for experiment 1

IV is changed breed; DV is measured flower count; constants are greenhouse conditions; no explicit control.

Step2: Identify variables for experiment 2

IV is watering solution type/concentration; DV is measured height; constants are sunflower type, environment; control is pure water group.

Step3: Identify variables for experiment 3

IV is humidity level; DV is measured height; constants are tree type, measurement frequency; control is outdoor tree.

Answer:

1)
IV: Breed of bushes
DV: Number of flowers
Constants: Greenhouse conditions (light, temperature, soil, etc.)
Control: None specified

2)
IV: Type/concentration of watering solution (pure water or salt solutions)
DV: Height of sunflowers
Constants: Sunflower type, growth duration (2 weeks), environment
Control: Sunflower watered with pure water

3)
IV: Humidity level
DV: Height of redwood trees
Constants: Tree type, measurement frequency (weekly), greenhouse (for indoor trees)
Control: Redwood tree left outside in normal conditions