Introduction to Science The Scientific Method

Metric System There are different ways to make scientific measurements of objects Length Mass Temperature Volume

Metric System In the USA, United Kingdom, Liberia and Myanmar use the English System of measurement They measure Distance in the foot Weight in the pound Temperature in the degree (Fahrenheit) Volume in the gallon

Metric System In science and in most areas of the world the Metric System is used to make measurements The metric system is a standard system that takes basic units and uses prefixes to determine amount

Prefixes In the metric system prefixes determine how many powers of ten a measurement is off from a base unit Different prefixes mean different sizes in measurement They are across all types of measurement

Prefixes

The Scientific Method How exactly did someone discover bacteria? How do we know what we breathe? Why do scientists think that the universe started with a bang?

The Scientific Method The scientific method is an organized approach to learn how the natural world works It is a system that allows for logical process It gives a framework to people who wish to discover, question or solve

The Scientific Method Observe Hypothesis Experiment Analyze results Draw conclusions

The Scientific Method Often considered the first step in the scientific method Observations are bits of knowledge that are gathered from the outside world

The Scientific Method Observations can be made anywhere by anybody However scientists often use instruments to help them record their observations

Example Experiment Observation: There seem to be more gnats buzzing around my head when I use Head and Shoulders

The Scientific Method A hypothesis is a proposed explanation for an observable phenomenon In science a hypothesis is an idea that is backed by previous knowledge and data

The Scientific Method It is very important for a hypothesis to be testable An experiment should be able to prove or falsify a hypothesis

Example Experiment Observation: There seem to be more gnats buzzing around my head when I use Head and Shoulders Hypothesis: If I used Head and Shoulders then gnats will be attracted to my hair. I can measure this by counting the number of gnats around my hair during three different thirty second periods.

The Scientific Method Experiments are set up to test specific variables These variables are the only things that should be tested in experiments Experiments that test multiple variables will not get clear results

The Scientific Method When conducting an experiment, scientists collect and record data Once the experiment is completed scientists review the data

Example Experiment Designing an Experiment: We will expose gnats to the same human after he has washed his hair with Head and Shoulders and after no shampoo. The amount of gnats attracted to the hair will be recorded as data

The Scientific Method Once data has been gathered it can be reviewed The data has to be looked at without bias in order to get a fair assessment at what is going on It often helps to compare the results of your experiment to other experiments of the same type

Example Experiment Analyzing Results: 15 gnats of 100 were attracted to the hair when using Head and Shoulders 45 gnats of 100 were attracted to the hair when using no shampoo

The Scientific Method Once the data has been analyzed, conclusions can be drawn from it These conclusions can be then compared back to your hypothesis They can prove or falsify your hypothesis Having your hypothesis falsified does not make it a bad experiement

Example Experiment Drawing Conclusions: Since more gnats were attracted to the person with no shampoo, Heads and Shoulders does not attract gnats.

That’s Just a Theory Several words have different meanings The word “set” has over 50 definitions The word “theory” is a term that has many different definitions

That’s Just a Theory In science, a theory is a proposed explanation for a question that is supported up by data This means that theories are things that can be supported by evidence and research Theories are not thoughts or ideas that come at random

Experiments Scientists work with variables during every experiment Correctly identifying and manipulating these variables is something every scientist must understand

Experiments There are three main types of variables Dependant Variable Independent Variable Control Variable

Variables In an experiment, the independent variable is the variable that is varied or manipulated by the researcher This means that the scientist actively changes something to make the independent variable

Variables The dependent variable is a response to the independent variable The dependant variable depends upon the independent variable to change Meaning… the dependant variable is the part that you measure

Variables The independent variable is something that the scientist changes The dependant variable is part that you measure

Variables The control variable is included in every experiment It is an example that shows what would have happened if nothing had been changed Generally the control variable is unchanged through an experiment

Now You Decide… Watch the following video clip List what the dependent, independent and control variables are Little gross… sorry https://www.youtube.com/watch?v=pRC5R1jRO58