The Scientific Method

The Steps to Success

The Scientific Method

What is the scientific method? It is a process that is used to find answers to questions about the world around us.

Is there only one “scientific method”?

No, there are several versions of the

scientific method.

Some versions have more steps,

while others may have only a few.

However, they all begin with the

identification of a problem or a

question to be answered based on

observations of the world around us.

They provide an organized method for conducting and analyzing an experiment.

What is a hypothesis?

It is an educated

guess based on

observations and

your knowledge

of the topic.

You state it as a

possible answer

to a question.

Stated in the “If….., then….” format

Example: IF I water three plants with different sodas, THEN the plant that receives Sprite will grow the tallest.

What is data? It is information gathered during an experiment.

It is organized into a data table and displayed visually as a graph.

Graphs BAR GRAPHS: can be used to

show how something changes over time or to compare items. have an x-axis (horizontal)

and a y-axis (vertical) the x-axis has time period or

what is being measured the y-axis has numbers for

the amount of stuff being measured.

good when you're plotting data that spans many years (or days, weeks...), has really big changes from year to year (or day to day...), or when you are comparing things.

LINE GRAPHS: can be used to show how something changes over time

x-axis has numbers for the time period

y-axis has numbers for what is being measured.

can be used when you're plotting data that has peaks (ups) and valleys (downs), or that was collected in a short time period.

Used for two sets of numerical data (ex: time and temp)

1. Choose a problem: State the problem as a question.

2. Research your problem: Read, get advice, and make observations.

3. Develop a hypothesis: Make a prediction about what will happen.

4. Design an experiment: Plan how you will test your hypothesis.

Steps of the Scientific Method

5. Test your hypothesis: Conduct the experiment and record the data.

6. Organize your data: Create a chart or graph of your data.

7. Draw conclusions: Analyze your data and summarize your findings.

Identifying Variables

Independent VariablesDependent VariablesControlled Variables (Constants)

Independent Variable – something that is changed by the scientistWhat is testedWhat is manipulated (changed)

3 Kinds of Variables

Dependent Variable – something that might be affected by the change in the independent variableWhat is observedWhat is measuredThe data collected during the

investigation “the numbers”Example: how tall the plant grew, how

far the paper airplane flew

Example:

Controlled Variable – a variable that is not changedAlso called CONSTANTSAllow for a “fair test”Everything in the experiment except for the IV should be kept constant

Give a detailed explanation of how you will conduct the experiment to test your hypothesis

Be clear about the variables (elements you change) versus your constants (elements that do not change)

A control is the group that you use as a comparison to see if change has occurred. Example: In a medicine study, the group

of people who don’t get the medicine are the control group

Procedure

Be very specific about how you will measure results to prove or disprove your hypothesis. You should include a regular timetable for measuring results or observing the projects (such as every hour, every day, every week)

Conclusion: your results or findings based on data collected during the experiment

Answer your problem/purpose statement What does it all add up to? What is the

value of your project? What further study do you recommend

given the results of your experiment? What would be the next question to ask?

If you repeat this project, what would you change?

Conclusion

For Example:

Students of different ages were given a jigsaw puzzle to put together. The scientist wanted to see if the students’ ages affected how long it took to put the puzzle together.

Independent Variable (IV):Ages of the studentsDifferent ages were tested by the scientist

Dependent Variable (DV):The time it took to put the puzzle together

The time was observed and measured by the scientist

Identify the Variables in this Experiment:

(1) Same puzzleAll of the participants were tested

with the same puzzle. It would not have been a fair test if

some had an easy 30 piece puzzle and some had a harder 500 piece puzzle.

Other constants: (2) same location, (3) same stopwatch, (4) same person timing the experiment

What were the constants?

An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.

Another Example:

IV: Sizes of nailsThese were changed by the scientist

DV: Number of paper clips picked upThe number of paper clips observed and counted (measured)

Constants: Battery, wire, type of nailNone of these items were changed

What are the Variables?

Let’s Practice!

If I use a heavier bowling ball, then the ball will travel faster down the lane.

IV: weight of bowling ballDV: speed it traveled down lane

2) If I use different brands of paper towels, then Bounty will absorb more water per minute than Sparkle or Quilted.

IV: brand of paper towelDV: amount of water

absorbed per minute

3) If I put 3 spider plants in different locations, then the plant in the sunlight will grow taller in a one-week period than the plants in the closet and basement.

IV: location of the plantsDV: height of plants