Nature of Science and Methods of Science Biological Basics Nature of Science and Methods of Science

What is Science SCIENCE IS….. a way in which answers related to NATURAL events are proposed a way in which people can learn and UNDERSTAND events in the NATURAL WORLD. based on OBSERVABLE EVENTS a study of the NATURAL WORLD a method of DISCOVERY and UNDERSTANDING by using a PROBLEM SOLVING process called the????

Essential Questions What are the differences between an observation and an inference? What are the differences among a control, independent variable, and dependent variable? What are the scientific methods a biologist uses for research? Why are the metric system and SI important? Copyright © McGraw-Hill Education Methods of Science

Ask a Question Scientific inquiry involves asking questions and processing information from a variety of reliable sources. Methods of Science Copyright © McGraw-Hill Education

Scientific Methods The methods scientists use to gather data and answer questions are referred to as Scientific Methods. Methods of Science Copyright © McGraw-Hill Education

1. OBSERVATIONS Scientific inquiry begins with OBSERVATION a direct method of gathering information in an orderly way. Uses 5 senses

Inferences The process of combining what you know with what you have learned to draw logical conclusions is called inferring or PREDICTING; the conclusions themselves are called INFERENCES. These are based on what you see, hear, smell etc.

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2. Form a Hypothesis A HYPOTHESIS is a testable explanation of a situation formed based on your observations. NOT just an educated guess anymore If the owl is up at night, then it is nocturnal. Methods of Science Copyright © McGraw-Hill Education

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How do we test a Hypothesis?

3. Controlled Experiments When a scientist conducts an EXPERIMENT They investigate a phenomenon in a controlled setting to test a hypothesis. Should only test ONE Variable at a time. Methods of Science Copyright © McGraw-Hill Education

2 Groups in an Experiment The control group in an experiment is the group used for comparison. An experimental group is a group exposed to the factor being tested.

Experimental variable A. Independent variable—the tested factor that might affect the outcome of the experiment AKA Manipulated Variable Usually the NONLIVING THING in the experiment What scientists can change/control in the experiment On a graph, variable on X-axis Methods of Science Copyright © McGraw-Hill Education

AKA Responding Variable Usually the LIVING THING in the experiment B. Dependent variable—results from or depends on changes to the independent variable. AKA Responding Variable Usually the LIVING THING in the experiment Change in this variable is caused by the Independent Variable On a graph, variable found on the Y-axis Copyright © McGraw-Hill Education Methods of Science

Experimental design Constant/Controlled Variable—a factor that remains fixed during an experiment while the independent and dependent variables change. Methods of Science Copyright © McGraw-Hill Education

4. Data gathering Not all scientific inquiry is based on controlled experiments Investigations rely on observation and collection of data rather than manipulating variables Copyright © McGraw-Hill Education Methods of Science

Types of Data As scientists test their hypotheses, they gather data– information gained from observations. Methods of Science Copyright © McGraw-Hill Education

Qualitative data are descriptions of what our senses detect. Types of Data Quantitative data can be collected as numbers, such as measurements of time, temperature, length, mass, etc. Qualitative data are descriptions of what our senses detect. Data is organized in notebooks and tables Methods of Science Copyright © McGraw-Hill Education

5. Analyze the Data After data collection, scientists use analyses to ask questions, such as “Has my hypothesis been supported?” or, “Are more data needed?” Patterns in data can be displayed in tables and graphs. Data analysis determines if the hypothesis is supported or rejected. Methods of Science Copyright © McGraw-Hill Education

When a hypothesis is supported by data from multiple investigations, the hypothesis is usually considered valid and is accepted by the scientific community. If the hypothesis is not supported by scientific investigations, the hypothesis is revised, and additional investigations are conducted .

6. Report Conclusions Before a scientist can publish their findings, it must be peer-reviewed. If the reviewers agree on the merit of a paper, it is published in a scientific journal. Other scientists use published papers to evaluate and develop their own research. Methods of Science Copyright © McGraw-Hill Education

Theory or Law Scientific conclusion can then become a Theory or a Law

Theory vs Law A THEORY is an explanation of a natural phenomenon supported by many observations and experiments over time. A SCIENTIFIC LAW describes relationships under certain conditions in nature, but does not explain why the relationship is the way it is. Theories do not become laws and laws do not become theories. The Nature of Science Copyright © McGraw-Hill Education

No Longer True…. Theories aren’t 100% true and laws are 100% true This is OLD School thinking

What is True… Because theories are continually being studied and data is continually being collected, theories can change over time. Because Laws are not continuously being studied, they remain constant.

Putting It All Together 1. Observation 2. Form Hypothesis 3. Experiment 4. Gather Data 5. Analyze Data 6. Report Conclusion

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Metric System Notes and Practice

Metric system is based on the power of 10. Meter is a measure of length Gram is a measure of mass Liter is a measure of liquid volume Celsius is a measure of temperature

Prefixes Kilo (k) 1000 103 Hecto (h) 100 102 Deka (da) 10 101 Base Unit 1 100 meter(m) liter(L) gram(g) Deci (d) 1/10 10-1 Centi (c) 1/100 10-2 Milli (m) 1/1000 10-3

Remember King kilo Henry hecto Died deca Unexpectedly base unit Drinking deci Chocolate centi Milk milli

Some things to remember when converting units. To convert from a larger to smaller metric unit you always multiply moving the decimal place to the right To convert from a smaller to larger unit you always divide moving the decimal place to the left

For every step upward (or to the left) on the chart you are dividing by 10 or moving the decimal one place to the left..

For every step downward on the chart you are multiplying by 10 or moving the decimal one place to the right.. Example:    To convert 2 kilometers to meters you move 3 steps down on the chart so you move the decimal 3 places to the right 2 kilometers = 2000 meters

Example:    To convert 345 milligrams to grams you move 3 steps up on the chart so you move the decimal 3 places to the left 345 mg = .345 g