Science Basics SNC2D

What is Science? When asked this question most students would immediately start to visualize Albert Einstein. But, is that what science really is? Are doing experiments science?

Science Defined The word science comes from the Latin word scientia. It can be defined as the effort to discover, understand, or to better understand how the natural world works. To simplify the definition, you can think of it as trying to figure out why or how the natural world works. With this definition, anytime you ask the question “why” or “how”, you are being a scientist.

The Natural World Another important idea in the definition is the term “natural world”. o This means things exist in the physical world and you can describe them through your senses. For example, you can see stars and describe them but they are just stars and they don’t have the power to control your life. o That is why astronomy is science and astrology is not.

The Scientific Method Scientists will often follow a procedure to discover facts about the natural world. Galileo made the scientific method famous. o It is just one of the methods that is used along with controlled experiments to make new discoveries. Galilean moons

Flowchart of the Scientific Method This is a simplified version of the flowchart found in your textbook.

The Hypothesis Using the scientific method, a scientist will ask a question about something they want to know more about. They would then formulate a hypothesis that can be tested. This is often written as an "if…then” statement.

The Controlled Experiment Once the hypothesis is made, the scientist can design a controlled experiment to test the hypothesis.

The Variables In a controlled experiment all variables are kept the same except the variable you are testing. o The things that stay the same are called the control variables. o The variable that the scientist changes are called the independent variable. o The data collected for analysis is called the dependent variable. To ensure that the data is valid, the experiment is replicated a number of times to make sure the results are always the same.

Examples of Variables in a Controlled Experiment You want to find out which gasoline gives you better fuel mileage. o Independent variable:  What will you control?  grade of gasoline o Dependent variable:  What will you measure?  how far you travel o Control variables:  Things that should not change?  same car for the test  drive at same speed  same driver  same weather conditions  windows closed What is the difference between qualitative data and quantitative data?

Representing Data Graphing is a very useful tool for representing quantitative data Types of graphs o Scatterplot o Line graph o Bar graph o Pie chart For most types of graphs the independent variable is on the x- axis and the dependent variable is on the y-axis However, sometimes a simple table is all you need to represent data (especially if it is qualitative data)

Observation vs. Inference Observations are things you directly observe. You notice that the ground is wet when you leave your house. You observe that the ground is wet. Inference is a mental process that uses what you observe to make a conclusion. o You can infer that the ground is wet because it rained before you came outside. o However, you can make mistakes with inferences. For example, what if the ground was wet because of melted snow?

From Hypothesis to Theory Once the hypothesis is proven true by repeated experimentation a scientist will publish the results for other scientists to review. Other scientists will also repeat the process to validate whether the hypothesis is true or not. Once a large number of scientists have validated the hypothesis, everyone will likely accept it as a fact. Once enough facts have been collected then they can be put together into a theory.

Final Thoughts An important thing about science is that it never stops growing. Theories are constantly evolving and being improved upon. If new information comes along that disproves a theory, scientists will throw away the old theory and immediately get to work on building a new theory based on the new and improved data. Science never says, “because I said so”, it is always based on evidence. Everything in science has been tested and verified in an effort to get to the truth about how the universe works.

Credits