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Scientific Method: steps used by scientists to solve problems

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Presentation on theme: "Scientific Method: steps used by scientists to solve problems"— Presentation transcript:

1 Scientific Method: steps used by scientists to solve problems

2 Steps in the Scientific Method/Experimental Design
Observation Hypothesis Experiment Data Collection/Results Conclusion Repeated Trials/Retest

3 1. Observations Gathered through your senses
A scientist notices something in their natural world Without explanation or interpretation.

4 What is an observation about this frog?
An example of an observation might be noticing that many salamanders near a pond have curved, not straight tails OR What is an observation about this frog?

5 2. Hypothesis A suggested solution to the problem. Must be testable
Usually written as If…Then… statements Predicts an outcome

6 Hypothesis An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.

7 A procedure to test the hypothesis.
3. Experiment A procedure to test the hypothesis.

8 Experiment vocabulary
Variable – things that change Constants -things that stay the same

9 Scientific Experiments Follow Rules
An experimenter changes one factor and observes or measures what happens.

10 Variables The factor that is changed purposefully to be tested is known as the independent variable. (Ask yourself, what am I changing?) The factor that is measured or observed is called the dependent variable.

11 What is the Purpose of a Control?
Control groups are NOT being tested (it’s the one you don’t do anything to) Controls are used for COMPARISON

12 The Constant The experimenter makes a special effort to keep all factors the same except the IV so that they will not effect the outcome. Those factors are called constants.

13 Example of Constants & Variables
In our example, suppose you hypothesize that salamanders near ponds have curved tails. You will observe salamanders near and away from a pond and count the number of curved and straight tails in each location.

14 What are the Variables in Your Experiment?
The location (near or away from a pond) is the independent variable The number of straight and curved tails is the dependent variable Collecting salamanders at both locations on the same day is a constant. What are some other constants?

15 To be a VALID experiment:
Two groups are required: the control & experimental groups There should be only one independent variable

16 Let’s review vocabulary!

17 4. Data/Results Must be organized
Can be organized into charts, tables, or graphs

18 Data/Results Results of the experiment
may be quantitative (measurable/ numbers) or qualitative (descriptive)

19 Quantitative OR Qualitative
The rose is red. Shawn is wearing a Hurley t-shirt. There are 25 students in this class. Water freezes at zero degrees Celsius The bug looked dead This watermelon contains a liter of water.

20 Graphs: Bar or line Use bar graphs for comparing data and when you have only one set of numbers ex. Graphing # of seeds that grew in different types of soil Use line graphs to display data over time and when you have two sets of numbers ex. Graphing number of people over the years

21 5. Conclusion The answer to the hypothesis based on the data obtained from the experiment.

22 In order to validate/verify the results, experiments must be retested.
Repeated Trials In order to validate/verify the results, experiments must be retested.

23 Theory vs. Law Theory: when many experiments show the same conclusion, the hypothesis can become a theory. Theories are NOT proven!! Law: fact of nature ex. gravity

24 Can you name the steps of the scientific method?
Now write down 4 quantitative and 4 qualitative statements that describe you.


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