1. UNIT 1 PART 1: THE SCIENTIFIC METHOD
The SCIENTIFIC METHOD uses a series of steps to solve problems.
All scientists try to solve problems in the same way.
This allows experiments to be repeated and verified.
If your experiment can’t be repeated with the same results, it is not valid.

2. A Good Experiment… Can be repeated with the same results.
Has a large sample size.
Is performed for a long time.
Tests only one variable. It has a control.
Is peer reviewed – looked at by others.
Does not have to agree with the hypothesis.
Is objective; not based on opinion; unbiased.

3. DESIGNING AN EXPERIMENT
Form a hypothesis
Define the variables
Describe the materials and conditions
Perform the experiment
Collect data
Interpret the data
Draw a conclusion

4. STEP 1: FORM A HYPOTHESIS
A hypothesis is an educated guess, or prediction, of what you think might happen.
It must be a statement, NOT a question.
It must be testable – a yes or no type statement, or an if…then statement. For example:
Plants need light to grow.
If plants do not have light then they will not grow as tall.

5. STEP 2: DEFINE THE VARIABLES
The INDEPENDENT variable is what is being tested, Ex. The amount of light. This is what YOU change in the experiment. On a graph, it is always on the X axis.
The DEPENDENT variable is what is measured when the independent variable is changed,
Ex. Height of the plants.
On a graph it is always
on the Y axis.
DEPENDENT
INDEPENDENT

6. STEP 3: MATERIALS AND CONDITIONS
What is needed for the experiment?
Plants, soil, pots, water
What conditions must be kept the same?
Amount of water, type of plants, type of soil, size of pots, temperature
What will be changed (independent)?
Amount of light
What will be measured (dependent)?
Height of plant

7. STEP 4: PERFORM THE EXPERIMENT
Collect what is needed and set up as many identical experimental setups that are required. All experiments have at least 2.
The experimental group(s) are being tested. They will have different amounts of the independent variable. (light)
The control group is “normal” and usually has none of what is being tested. (kept in dark)

8. STEP 5: COLLECT DATA
As the experiment is performed, make observations and measurements. (height of plants)
These may include temperature readings, height, weight, amounts of variables, etc.
Data is often organized into tables to make it easier to read and graph. These usually go in increasing or decreasing order of the independent variable in the first column with the dependent variable in the second column. (make a table for our example)

9. STEP 6: INTERPRET THE DATA
Compare your experimental data to the control data
Make a graph and/or drawing
Are there any trends in the data?
Were there any problems during the experiment?
For our example:
Label each axis
Make a scale

10. STEP 7: DRAW A CONCLUSION
Does your data support your hypothesis?
If not you must reject your hypothesis.
Explain your results either way. This means you must describe WHY your hypothesis is supported or rejected.
If your hypothesis is rejected, how could you change it?