Finding the Control Group
This group is compared to the other groups as the one that does not get the change or independent variable.
The control group
The one thing that is varied in the experiment.
independent variable.
Is the thing that will change, that you intend to measure.
dependent variable.
Must stay the same between the groups.
control variables.
The first step of the scientific method.
Make an observation.
You decide you want to compare which music makes you fall asleep faster. Week 1 you listen to rock music. Week 2 you listen to country music. Week 3 you listen to classical music. Week 4 you listen to no music. What week is the control?
Week 4
Is the size of fish affected by the depth of the ocean they live? What would be the Independent Variable?
depth of ocean.
A group of scientists test the behavior that women find men without earrings more attractive than men with earrings. What is the Independent Variable?
Men wearing earrings.
You are testing if different amount of light affect plant growth. What needs to be the same between all the plants for experiment to be valid?
Soil, fertilizer, type of plants, amount of water, time of test
The if...then statement that is testable.
a hypothesis.
Bart believes that mice exposed to radio waves will become extra strong. He has two groups of ten mice. He places group A near a radio for 5 hours. Group B that had not been exposed to radio waves. To test the hypothesis he placed a wood block to block the door to the mice food. After 5 hours he found that 8 out of 10 of Group A mice were able to push the block away. 7 out of 10 of Group B mice were able to do the same. What group is the control group?
Group B
Is photosynthesis production of starch faster when plants are exposed to different amounts of light? What would be the Dependent Variable?
amount of starch produced.
Children who entered kindergarten at age 5 were compared with children who entered kindergarten at age 6 on measures of academic achievement taken at grade 5. Results indicate that children who entered kindergarten at age 6 scored higher on standardized tests than those kids that entered at age 5. What is the Dependent Variable?
score on standardized test.
You want to see if students do better on a test if they study with music. You divide up one class into 2 groups of 15 students. Group A listens to music while studying their notes for 1 hour a night. Group B studies their notes with no music for 1 hour a night. After two weeks, a comprehension test was given to all students after they had studied their notes in silence or with music turned on. What are the controls?
two weeks, 1 hour a night, 2 groups of 15 students, test
The part of the scientific method that data is collected.
the results
Pea plant clones are giving different amounts of water for three-week period. The first pea plant receives 400 milliliters a day. The second pea plant receives 200 milliliters a day. The third pea plant receives 100 milliliters a day. The fourth pea plant does not receive any extra water: the plant only receives natural ways of receiving water. The heights of the pea plants are recorded daily. What pea plant is the control?
the pea plant with no water.
Spending time with a pet animal decreases the amount of stress right before taking a test. What is the independent variable??
time with pet.
A researcher wants to investigate the types of social behaviour that develops in children in day care depending on the amount of time the child spend in day care. What is the Dependent Variable?
Social behaviour in children.
One tank of gold fish is fed the normal amount of food once a day. A second tank is fed twice a day. A third tank is fed four times a day during a six week study. The fish’s weight is recorded daily. What are the controls?
3 tanks of goldfish, 6 week study, weight recorded daily.
When experiments have been conducted multiple times, data is analyzed and the results are shared and compared with others, what are you ensuring?
Reliability
The design of a good experiment that only tests one variable at a time.
One control group, independent variable, dependent variable, and control variables.
Students at a University were split into two groups and each received a different text for a philosophy course. Once group received a traditional text book, while the other received an interactive textbook on a tablet computer. After the course, the final exam marks between the two groups of students was compared. What is the dependent variable?
final exam marks
Three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. The heights of the trees are measured once a week. Independent Variable? and Dependent Variable?
Independent Variable-different humidity levels
Dependent Variable-Height of redwood tree
In order for a experiment to be valid and develop creditable data this is needed.
A control group.
Explains a natural phenomenon, a explanation of many different hypothesis that have been tested widely.
A theory.