Vocabulary
The Variable the scientist changes
Independent/ Test Variable
the first step in the scientific method
making an observation or asking a question about the natural world.
using your five senses
Observation
A scientist wants to determine whether the amount of water given to bean plants affects their growth. Group A receives 50 mL of water each day, Group B receives 100 mL, and Group C receives 150 mL. All plants are kept in the same type of soil and receive the same amount of sunlight. What is the independent variable?
The amount of water given to each plant.
A scientist tests a new fertilizer.
Question: Which group is the experimental group?
Group B
The Variable that the scienist measures
Dependent/ outcome variable
the second step in the scientific method
gather information
one!!
Students investigate whether different types of soil affect how quickly a plant grows. They record the height of each plant every three days for four weeks. What is the dependent variable?
Plant growth/height.
In the fertilizer experiment, which group serves as the comparison?
Answer: Group A — the control group
The variable that we keep the same in the experiment to make the experiment valid
Constants/Control Variable
the third step in the scientific method
state a hypothesis
a company wants to test a new dog food that is supposed to help overweight dogs lose weight. 50 dogs are chosen to get the new food, and 50 more continue their normal diets. After one month, the dogs are checked to see if they lost any weight. What is the dependent variable and independent variable?
IV: New dog food DV: Weight lost
A coach investigates whether different types of warm-ups affect volleyball players' serving accuracy. One group stretches, another jogs, and another performs jumping exercises. All players serve from the same distance using the same type of volleyball. Name two control variables.
A basketball coach wants to know if a new shooting technique improves free-throw accuracy.
Team A uses the old technique.
Team B uses the new technique.
Question: Which team is the experimental group?
Answer: Team B
Group that receives the test variable
Experimental group
the 4th step in the scientific method
Conduct an Experiment
A student asks:
“Does the amount of sunlight affect how tall a plant grows?”
Question: What step is this
Question
A group of students wants to know whether a new type of fertilizer increases plant growth.
After four weeks, students compare the height of the plants. Which is the experimental group?
Group B, because it receives the variable being tested.
A scientist tests two types of fertilizer.
Question: Can we automatically call Group A the control group?
Answer: No.
Group that does not receive the test variable (Normal Conditions)
Control Group
the last two steps in the scientific method
organize and analyze data and state a conclusion
A student follows this process:
Observation → Question → ______ → Experiment → Analyze Data → Conclusion
Question: What step is missing?
Hypothesis
Students test whether background music affects memory.
However, Group 2 takes the test immediately while Group 1 waits 20 minutes before taking it.
Question: What is wrong with this experiment?
The time between studying and testing is not controlled. It could affect the test scores, making it difficult to know whether music caused the difference.
A researcher wants to know if drinking water before a test improves concentration.
Question: Why is Group B useful?
Answer: It provides a control/comparison to determine whether drinking water affected performance.