Question

1. for the experiment shown below, identify the following variables and groups location a location b a. independent variable: b. dependent variable: c. controlled variables (give at least 3): d. control group: e. experimental group: f. for the experiment in the previous problem, write a testable hypothesis in the \if...then...because...\ format. 10. a classmate suggests a new hypothesis: \hamsters are better and rats because hamsters are cuter.\ explain why this hypothesis is not scientific. 11. why does it make sense for scientists to test just one variable in a controlled experiment? 12. explain the difference between a control group and an experimental group.

Explanation:

Step1: Identify independent variable

The factor being changed is nitrogen addition, so the independent variable is the addition of nitrogen.

Step2: Identify dependent variable

The outcome likely being measured is something about the grass, so the dependent variable could be grass growth (or another measurable aspect of the grass like height, density etc.).

Step3: Identify controlled variables

Possible controlled variables are: type of grass, amount of sunlight, amount of water, soil type.

Step4: Identify control group

The group without the variable being tested is the control group. So the control group is the grass in Location B with no nitrogen added.

Step5: Identify experimental group

The group with the variable being tested is the experimental group. So the experimental group is the grass in Location A with nitrogen added.

Step6: Write hypothesis

If nitrogen is added to the grass, then the grass will grow taller because nitrogen is an essential nutrient for plant growth.

Step7: Answer question 10

The hypothesis "Hamsters are better than rats because hamsters are cuter" is not scientific because "cuteness" is a subjective quality. Scientific hypotheses must be testable and objective. There is no objective way to measure "cuteness".

Step8: Answer question 11

Testing just one variable in a controlled experiment makes sense because it allows you to clearly determine the effect of that variable. If multiple variables are changed at once, it is impossible to know which variable caused the observed results.

Step9: Answer question 12

A control group is a group in an experiment that does not receive the treatment (the variable being tested) and is used for comparison. An experimental group is the group that receives the treatment (the variable being tested) so that the effects of the treatment can be observed.

Answer:

a. Addition of nitrogen
b. Grass growth (or other measurable aspect of grass)
c. Type of grass, amount of sunlight, amount of water, soil type
d. Grass in Location B with no nitrogen added
e. Grass in Location A with nitrogen added
f. If nitrogen is added to the grass, then the grass will grow taller because nitrogen is an essential nutrient for plant growth.

1. The hypothesis is not scientific because "cuteness" is a subjective quality and scientific hypotheses must be testable and objective.
2. Testing one variable allows you to clearly determine the effect of that variable. Multiple - variable changes make it impossible to know which variable caused the results.
3. A control group does not receive the treatment and is for comparison. An experimental group receives the treatment to observe its effects.