Science : is an organized way of using evidence to learn about the natural world
Scientific thinking usually begins with: Observations : the process of gathering information about events or processes in a careful, orderly way. Observations generally involve using the senses.
Information gathered from observations is called data .
Quantitative data : expressed as numbers, obtained by counting or measuring
Qualitative data : descriptive and involve characteristics that can’t usually be counted
Scientists may use data to make inferences .
I nference: an interpretation
or explanation of an
After initial observations, scientists propose one or more hypothesis .
Hypothesis : a proposed scientific explanation for a set of observations. Scientists generate hypothesis based on prior knowledge, logical inference, and informed creative imagination.
Scientific hypotheses must be proposed in a way that enables them to be tested.
Science is a way of knowing science is an ongoing process scientific understanding is always changing. Good scientists are skeptics. Scientists assume that in the universe, basic natural laws govern all events and objects.
Identify a problem
Gather Information (research)
Test the hypotheses
Analyze the results
Variables : The factors in an experiment that can change. Examples: equipment used, type of material, amount of material, temperature, light, time, etc.
Whenever possible, a hypothesis should be tested by an experiment in which only ONE variable is changed at a time! This type of experiment is called a controlled experiment
The variable that is changed is called the manipulated or independent variable.
The variable that is observed and that changes in response to the manipulated variable is called the responding or dependent variable
Variables in experiment that need to stay the same!!
a standard to which your experiments can be compared.
Problem – which type of dish soap works the best???
Hypothesis – Dawn works the best at washing grease off of a pan.
type of soap used
- how much grease is left on pan (what you measure!!!)
types of pans, amount of soap, temperature of water, type of washer, etc.
wash a pan without any soap!!!
Recording and Analyzing Results Often done with technology
Experiments Must Be Repeated
you cannot do an experiment once and get valid results
Drawing A Conclusion
use the data from an experiment to evaluate the hypothesis and draw a conclusion
Science assumes that experimental results can be reproduced because nature behaves in a consistent manner
Scientists often publish reports in scientific journals, where other scientists review the experiments to make sure there were no flaws.
Scientists also often repeat experiments done by others to check for flaws.
When Experiments are Not Possible
example: determining the effect
on people of a chemical suspected
of causing cancer
How a Theory Develops
As evidence from numerous investigations builds up, a particular hypothesis may become so well supported that scientists consider it a theory
Scientific Theory: a well tested explanation that unifies a broad range of observations.
theory that has never (and scientists think will never) be disproven
A theory or a law enables scientists to make accurate predictions about new situations.