th
8
Grade Science
State Standard Number: SPI
0807.Inq.1
Local Standard Number: 801
INTROIDUCTION
Design a simple experimental procedure with an
identified control and appropriate variables.
Key vocabulary:
hypothesis
experiment
variable
independent variable
dependent variable
control factor
control setup
experimental setup
Design a simple experimental procedure with an
identified control and appropriate variables.
Key concepts/skills:
Level 1: Define key vocabulary.
Level 2: Given a hypothesis, identify independent and dependent
variables.
Level 3: Compare and contrast experimental setup and control
setup (identify control factors.)
Design a simple experimental procedure with an
identified control and appropriate variables.
Steps in the Scientific Method (Review of Previous Learning)
1. Observation2. Question3. Hypothesis4. Testing5. Analysis6. Conclusion-
Design a simple experimental procedure with an
identified control and appropriate variables.
For this standard, we will concentrate on understanding steps
three and four, “hypothesis” and “testing.”
Design a simple experimental procedure with an
identified control and appropriate variables.
Today we will practice this skill:

Analyzing the hypothesis to determine what the
independent and dependent variables are.
Identify the variables in the hypothesis
Example
Hypothesis: Adding salt to water will raise the boiling point of the water.
Independent variable - The variable that you, the scientist, will
change on purpose to see what effect it has on the results of the
experiment.
Question: What is the independent variable in the above hypothesis?
Answer: Adding salt is the independent variable because you can change
whether you add salt to the water or not and how much salt you add
to see how it changes the boiling point of the water.
Identify the variables in the hypothesis
Example
Hypothesis: Adding salt to water will raise the boiling point of the water.
Dependent variable - The variable that depends on how you
change the independent variable. It is the result of the test that you
will record.
Question: What is the dependent variable in the above hypothesis?
Answer: The boiling point is the dependent variable because it depends on
how you change the amount of salt in the water. It is the result that
you will measure and record.
Practice Part 1
Identify the independent variable in each of following hypotheses:
1. Warmer temperatures decrease the hatching times for robin eggs.
2. Crickets chirp more when they get more food.
3. Dogs howl more when the moon is full.
Answers:
1. temperature-you change the temperature in each test
2. amount of food-you change the amount of food in each test
3. amount of moonlight-you change the amount of moonlight in each test
Practice Part 2
Identify the dependent variable in each of following hypotheses:
1. Warmer temperatures decrease the hatching times for robin eggs.
2. Crickets chirp more when they get more food.
3. Dogs howl more when the moon is full.
Answers:
1. hatching time-it depends on the temperature
2. amount of chirping-it depends on the food
3. amount of howling-it depends on the amount of moonlight