Do Now…

How is a scientific investigation done?

Methods of ScienceObjectives:- Differentiate among control, independent variable, and dependent variable- Identify the scientific methods a biologist uses for research-Describe the difference between Theory and a Law

Ms. Scerra

The Scientific Method

• Biologists work in different places in order to answer a question they may have. • Biologist all use similar methods to gather information

and to answer questions, the Scientific Method• Even though scientists do not use scientific methods in

the same way each time they conduct an experiment, they observe and infer throughout the entire process.

Quick Review• Observation – direct way of gathering information in an

orderly way.• Inference – the process of combining what you know

with what you have learned to draw a logical conclusion.

Form a Hypothesis

• After observing, reviewing prior information and questioning, a biologist is able to format a hypothesis.• A Hypothesis is a testable explanation of a

situation.• A Hypothesis that is supported through experiments

and data is then accepted in the scientific community.

Serendipity

• The occurrence of accidental or unexpected but fortunate results.

For example: • The discovery of Penicillin.• A petri dish was left out overnight and the next

morning the scientist discovered a green fuzzy substance growing on it. Later they discovered it properties that it destroyed bacteria cells.

Think-Pair-Share• Can you think of an event that was serendipitous?• Has serendipity occurred in your life?• Can you think of something that came about or was

discovered through serendipity?

Experimental Design• With that hypothesis, an experiment is created.• Experiment – investigation of a phenomenon in a controlled

setting to test a hypothesis.• Each Experiment has: • Control Group – a group used for comparison.• Experimental Group – the group exposed to the factor being

tested.• Independent Variable – the tested factor and may affect the

outcome of the experiment.• Dependent Variable – results from or depends on changes to the

independent variable. • Constant – a factor that remains fixed during an experiment.

Variables

Collect and Gather Data

• Data- information gained from observations.• Quantitative Data- measurements of time, temperature,

length, or other factors.• Qualitative Data- descriptions of what our senses detect.

Displaying Data-Organize your data into a chart-Make a graph out of the chart

Analyze Your Data to Form a Conclusion• What can we conclude from this graph?

Report Your Conclusions

• After experimenting you must come to some type of conclusion either disproving or proving your hypothesis!

• Conclusions are published so others can review the results and discuss the merit of the experiment.

Do Now!

• What is the SI unit system of measurement?

• Why is it used?• What unit would I use to describe length?

Mass? Volume?

Objectives

• Explain the nature of science• Compare and contrast the English and

metric systems• Practice conversions between metric units.

Nature of Science• *Uses Scientific Theory…• Theory– Explanation of natural phenomenon supported by

many observations and experiments over time– Explains how or why something happens.– Ex: The Big Bang Theory (not the show!), Cell Theory

• Law– A statement about an event that occurs in nature– Doesn’t give us the “how” or “why” explanation– Usually expressed as a mathematical equation– Ex: The Law of Gravity, Boyle’s Law, etc.

Expands Scientific Knowledge

• Science is under constant reevaluation of what is known.

• Ex. Classification, Food Pyramid• Can lead to new knowledge• Reevaluation cycle continues!

Challenges Accepted Theories

• Scientists debate each other’s ideas• Science accommodates new information

as it is discovered

Questions Results

• Scientist can find data that is not consistent with current scientific understanding

• These inconsistencies often lead to further investigations

Test Claims

• Conclusions are reached after – Controlled experiments– Unbiased investigations– Large amounts of data

Undergoes Peer Review

• Experiments are reviewed by scientist’s peers. (Peer review )

Evaluated by other scientists who are in the same field or who are conducting similar research.

Measurements Used in Science

• Different methods used for measuring• International System of Units (SI)- what

scientists all over the world use – Measured in groups of 10

Length - SI

• SI uses the meter

• Measures how long something is• Tools: Ruler, meter stick

Volume

• SI uses m3

• Most often we use liter • Measures how much space

Something takes up

Mass and Weight

• Mass = how much matter something has• SI units are kilogram (kg)• Weight = force of gravity on an object

Time and Temperature

• Time: period between two events– SI unit is seconds (s)

• Temperature: how much heat contained in an object (how hot or cold something is)– SI unit is Kelvin (K)– Scientists often use Celsius (C)

Conversions

• 4 kiloliters= ___________ hectoliters

• 36.87 millimeters= ________ decameters

• 0.098 meters = ___________ micrometers

• 56.7 decimeters= _________ decameters

Now Work on Metric Mania