Ch. 1

What is science?

The Unknown

• In the past, myths and legends were used in order to explain the unknown.– Diseases are caused by evil spirits.– The world is flat.– The sun revolves around the earth.

• Today, science used in order to explain the unknown.

How were these statements first proven

wrong?• Diseases are caused by evil spirits.

– Germ Theory • Louis Pasteur – 1862

• The world is flat.– Ancient Greece (approx 384B.C)

• Lunar Eclipse.

– Pictures from space.

• The sun revolves around the earth.– Galileo – 1610

The Goal of Science

• Science is an organized way of using evidence to learn about the natural world

• Investigate and understand the natural world.

• Explain events in the natural world.

• Use explanations to make useful predictions.

Current scientific research

• What is being studied by scientists today?– AIDS– Cancer– Heart Disease– Stem cells– And MUCH more!

How has scientific research improved our lives?

• Longer average life span.– Average life span of an American is now

approximately 74 yrs.– Average life span 2,000 years ago was

approximately 24 yrs.• Many diseases and illnesses are now

curable or can be treated.– Many forms of cancer can be cured or

treated.– Penicillin (Alexander Fleming) can be

taken to prevent infections.• Better understanding of how our bodies work and

the world around us

Why is studying science important to us?

• Learn to look at things more objectively.

• Approach problems from different angles.

• Ask more questions.• Become more analytical.• Understand issues concerning health,

society and the environment.• Gain an understanding of ourselves and

the world around us.

Biology• Biology is the study of living

organisms.• Biology consists of many

specialized fields.–Zoology, ecology, genetics, microbiology, molecular biology, evolutionary biology, marine biology, anatomy and physiology….

Data Collection and Analysis

Chapter I

A. The Metric System1. The metric system (International

System of Units) is used when describing experiments and data.

2. Based on multiples of 10.

B. Length

1. The basic unit of length is the meter (m)

C. Metric Units of Length

1. 1 meter (m) = 100 centimeters (cm)

2. 1 cm = 1x10-2 m (1/100)3. 1 m = 1,000 millimeters (mm)4. 1 mm = 1x10-3 m (1/1000)5. 1 m = 1,000,000 micrometers

(μm)6. 1 μm = 1x10-6 m (1/1,000,000)

C. Metric Units of Length

7. 1 m = 1,000,000,000 nanometers (nm)

8. 1 nm = 1x10-9 m (1/1,000,000,000)9. 1000 m = 1 kilometer (km)10. 1,000,000 m = 1 megameter (Mm)11. 1,000,000,000 m = 1 gigameter

(Gm)

D. Volume

1. Amount of space an object occupies.

2. Metric Units are the Liter (L) for liquids.

3. Metric Units are cubic centimeters (cc or cm3) for solids.

E. Mass1. The amount of matter in an object.2. Metric measurement is the

kilogram (kg). 3. Small objects are measured in

grams (g).4. 1 kg = 1000 g5. 1g = 1000 mg

F. Temperature

1. Metric system uses the Celsius scale

2. Water freezes at 0ºC and boils at 100ºC

3. Body temperature is 37 ºC

G. Converting Measurements

1. Converting Measurementsa. What unit your measurement is given?b. What unit should it be expressed?c. What is the conversion factor?d. The conversion factor is the relationship between

the given units and the desired units. The conversion factor is expressed as a fraction.

e. The units should cancel out leaving the desired units.

Accuracy vs. Precision• Accuracy = How close a measured

value is to the true value.• Precision = How close the measured

values are to each other.

High accuracy, high precision

High accuracy, low precision

Low accuracy, high precision

IV. The Scientific Method

Chapter 1

Science As a Way of Knowing

• Science is an ongoing process.• Scientists continually ask

questions.• Good scientists are skeptics.

How to Use the Scientific Method

1. The first step in the scientific method is to make observations and ask a scientific question or state a problem. a. Be as specific as possible.

i. Allows the scientist to devise better experiments.

How to Use the Scientific Method

2. The second step is to collect background information.a. Literature, peer feedback, prior

research, databases.

How to Use the Scientific Method

3. The third step is to form a hypothesis based on your observations.

a. A hypothesis is a possible explanation.

b. Must be testable.

How to Use the Scientific Method

4. The fourth step is to test the hypothesis.a. This is done by performing controlled,

reproducible experiments.

How to Use the Scientific Method

5. Controlled experiments allow researchers to isolate and test the effects of a single experimental variable.1. Variable - the factor in the

experiment that can change. (temperature, light, time…)

2. Only one variable should be tested at a time al other variables should be kept the same.

How to Use the Scientific Method

6. Identify the manipulated, responding and controlled variables.

a. Independent variable - the variable that is changed (light, temperature, time…)

b. Dependent variable - the variable that changes in response to the manipulated variable. (result, depends on the independent)

c. Controlled variables - The variables which do not change.

How to Use the Scientific Method

7. Set up and run the experiment

a. Control setup - Exposed to normal conditions.

b. Experimental setup(s) - exposed to the manipulated variable.

How to Use the Scientific Method

8. The fifth step is to record and analyze the data.

a. Graphs, charts.

9. The sixth step is to form a conclusion based on the data

Reproducing an Experiment

1. The experiment must be reproducible.2. Scientists are continuously repeating

and varying experiments to test a hypothesis.

3. When a hypothesis is tested numerous times it may become a theory.a. A well-tested explanation.

4. A theory can become a scientific law.a. Newton’s law of gravity

Reproducing an Experiment

5. What if a scientist performs the same experiment as another scientist and the results do not agree. What might be the reason for this?a. Error in the first experiment.b. Second scientist did not correctly follow

the procedure or duplicate the experiment.c. First scientists results due to chance.d. Second scientist introduced a second

variable.

Possible Errors When Applying the Scientific

Method1. The hypothesis may not be

specific enough.2. Errors in collecting data.3. Errors in analyzing data.4. Mathematical errors.5. Experimental errors.6. Procedural errors.

Summary

1. Make observations and ask a scientific question or state a problem

2. Background research.3. Form a hypothesis.4. Test the hypothesis.5. Record and analyze the data.6. Form a conclusion.