Scientific Methods and Processes. I. Introduction to Science 1. What is science?

Scientific Methods and Processes

I. Introduction to Science

1. What is science?


1. What is science? An organized, step-by-step process used to

solve problems or investigate nature.


2. What are some characteristics of scientists?


2. What are some characteristics of scientists? Organized, curious, intelligent, driven, honest,

systematic, creative, hard-working, caring


3. What do scientists do?


3. What do scientists do? Investigate things that happen in nature. Try to answer scientific questions. Try to solve problems of society. Observe nature Perform experiments

II. Scientific Process

1. Identify a problem, question or subject to study.

2. Make initial observations. a. Determine what needs to be studied. b. Observations need to be made without bias

– ideas about what the scientists should see without any proof – prejudice.


3. Create a hypothesis. a. Hypothesis is a proposed answer to the

question. b. Hypotheses give the scientist a place to

begin testing. c. Does not need a lot of proof to be useful.


4. Test the hypotheses. a. May be done by making more observations. b. May be tested by running experiments. c. Hypotheses are tested to see which ones

have some proof.


5. Develop a theory. a. A theory is the best answer to the question. b. Theories are never completely proven. c. Theories are considered good if we can

repeat the process; it stands up to new information; and can be used to make predictions.

III. Experimental Design

1. A good experiment can have only two variables.

a. Variables are parts of the experiment that can change.

b. Variables must be easy to observe and be measurable


c. Independent variable is changed by the scientist.

d. Dependent variable is changed as a result of the independent variable being changed.

e. The dependent variable is measured and recorded


2. An experiment is poorly designed if more than two variables are tested.

a. Everything else should remain constant. b. If two independent variables are used at the

same time, the experiment cannot show which one caused the change in the dependent variable.

c. Two dependent variables may interfere with each other.

d. If a third variable is needed, do the experiment again.


3. Variables must be chosen carefully to accurately test the hypothesis.

4. Variables need to be clearly defined. 5. Measurements need to have the proper

units.

IV. Reporting Data

1. Data is recorded in a table. a. Usually, the independent variable is on the

left and the dependent variable is on the right. b. Tables give the scientist a quick way to look

for relationships in the data.

IV. Reporting Data

Distance Time

10 meters 1.5 seconds





IV. Reporting Data

2. For more detailed analysis, scientists use graphs.

a. Three graphs are line graphs, bar graphs, and pie charts.

b. Different graphs are used for different kinds of data.

c. The scale (spacing) is very important to show the relationship clearly.

IV. Reporting Data

3. Line graphs are used to see the relationship between two variables that are measured.

a. The independent variable is on the y-axis and the dependent variable on the x-axis.

b. Data is placed as points on the graph paper and lines are used to connect the dots.

IV. Reporting Data

4. Bar graphs are used to show a variable that is counted over a period of time or during repeated intervals.

a. The dependent variables are displayed as columns or rectangles with the values displayed on the y-axis.

b. The time intervals are displayed on the x-axis.

c. Can show more than one set of intervals by using two different columns.

IV. Reporting Data

5. Pie graphs are used to show percentages of a whole.

a. The whole is represented by a circle. b. The percentages are shown as different

sized pieces of the pie.

Study Guide

A. Definitions

1. Hypothesis – Proposed answer to a scientific question that can be tested.

2. Theory – The best answer to a scientific question that has been tested.

3. Law – A scientific relationship that can be shown mathematically.

4. Bias – A strongly held opinion.

Study Guide

5. Variable – A factor in an experiment that can change.

6. Constant – A factor in an experiment that does not change.

7. Independent Variable – The part of an experiment that is being tested; The part in which the scientist makes the changes in the design of the experiment.

Study Guide

8. Dependent Variable – The part of the experiment that is measured and recorded; it changes in response to the independent variable.

9. Control Group – A group of participants in an experiment that does not receive the treatment.

Study Guide

B. Short Answer

1. Repeat of the process gets the same result; New information supports the theory; Can make predictions from the theory.

2. The hypothesis is the beginning of the process, the theory needs more proof.

Study Guide

3.A. Independent Variable – Doses of Vitamin C.

Dependent Variable – Number of people with colds.

Hypothesis – The more vitamin C a person takes less likely they will get a cold.

B. Independent Variable – Value of the Car

Dependent Variable – Number of times stolen.

Hypothesis – The more expensive the car, the more likely it is to be stolen.

Study Guide

4. A. Line Graph

B. 40.00 m/s

C. 8 sec

5 A. Bar

B. December, October

C. $825.00

Study Guide

6. A. Circle Graph or Pie Chart

B. Coal

C. 15%

D. Solar, Wind, Hydroelectric, Geothermal

7. Organized, curious, intelligent, driven, honest, systematic, creative, hard-working, caring

Study Guide

C. Multiple Choice

1. C

2. D

3. D

4. A

5. B

6. B

Study Guide

7. C

8. A

9. D

10. A

Scientific Methods and Processes. I. Introduction to Science 1. What is science?

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