Water and Experimental Group

Name:________________________ Period: ______
Identifying Scientific Variables
For the following experiments identify the three variables for each experiment and what the experimental and control groups should look like.
1) TQ: Does the type of fertilizer affect the number of flowers on a rose bush?
Scenario: Different rose bushes are grown in a greenhouse for two months. The scientist is interested in seeing how fertilizer affects the growth of the plants. The number of flowers on each bush is counted at the end of the experiment.
Manipulated Variable-
Type of fertilizer
Responding Variable
Number of flowers on the rose bush
Controlled Variable(s)
Amount of water, type of plant, greenhouse
d. Experimental group (what should the experimental group(s) look like?)
My experimental group should have variations of fertilizer
e. Control Group (what should the control group look like?)
My control group should have no fertilizer in the plants pot.
2) TQ: Does the amount of salt given to a plant affect plant height?
Scenario: You water three sunflower plants with salt water. Each plant receives a different concentration of salt solution. A fourth plant receives pure water. After a two week period, the height is measured.
a. Manipulated Variable
The amount of salt given
b. Responding Variable
_The height of the plants
c. Controlled Variable(s)
_The sunflower, the water, amount of light
d. Experimental group (what should the experimental group(s) look like?)
The experimental group should have different concentrations of salt.
Control Group (what should be included in the control group?)
The control group should have pure water
3) TQ: Does humidity affect the growth (height) of a tree?
Scenario: 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.
a. Manipulated Variable
_Humidity levels
b.