The 3rd step of the Scientific Method
Experiment
The variable that is measured
Dependent Variable
An educated guess that predicts the outcome of an Experiment, written as an "if, then" statement
If, then
One grape is placed in tap water and another grape is placed in salt water. The change in their mass is measured after a day.
What are the Independent and Dependent variables?
IV: type of solution
DV: Mass of grape
The 1st step of the Scientific Method
Problem
The group that does not receive treatment and is used as a comparison
Control
TRUE or FALSE: It is okay to measure more than one variable in an experiment
FALSE
TRUE or FALSE. It is okay if your results after doing an Experiment don't support your hypothesis.
TRUE
The heart rate of a goldfish is measured. The goldfish is then placed in cold water and the heart rate is measured again.
Identify the IV and DV.
IV: temperature
DV: heart rate
The 5th step of the Scientific Method
Conclusion
The variable is changed in the experiment
Independent Variable
Does amount of sleep affect test performance?
Write a HYPOTHESIS for this problem.
If someone gets more sleep then they will perform better on their test.
A stapler is used to staple 100 papers, it jams 5 times during the trial. A different brand of stapler performs the same test; it jams 22 times.
Identify the IV and DV.
IV: Brand of stapler
DV: Number of paper jams
The 2nd step of the Scientific Method
All the parts of an Experiment that stay the same to ensure only one variable is being tested.
What type of relationship does the graph below illustrate?
Indirect Relationship
Does sunlight affect plant height?
Write a HYPOTHESIS for this problem.
If a plant gets more sunlight then it will grow taller.
Javier sleeps 9 hours the night before his science exam. His twin sister has the same exam and sleeps 6 hours the night before the test. Afterwards, they compare their scores.
Identify the IV and DV.
IV: Amount of Sleep
DV: Score on Science Exam
The final step of the Scientific Method
Communication
Experimental Group
You are testing to see if amount of sunlight affects plant growth, which of the following would be the control group?
#1
A bug repellent is sprayed on one arm the other arm is not sprayed. The number of bug bites is recorded after 2 hours.
Write a HYPOTHESIS for this problem.
If bug spray is used then the person will have less bug bites.
Group A exercises for a month. Group B does not exercise. They measure the amount of weight they gained.
Identify the IV and DV.
IV: Exercise
DV: Weight gained