1.2 - Scientific method

what is the scientific method

recognition of problem → collection of information → making hypothesis → testing hypothesis → collection of data → make conclusion

Identifying a problem

where scientific investigation begins

Collecting information

may involve observation and lit reviews

Independent variable

factor you change (use units)

Dependent variable

factor you measure (use units)

Control variables

factors you control … ALL ____ THE SAME

making a hypothesis

definite statement that links the variables and allows for a prediction to be made

what is a fair test

a test that has an experimental and a control group

quantitative data

measured

qualitative data

observed

repetition

doing the same experiment multiple times

what must tables have

titles

columns - independent in left

columns have headings with variables and units

what must graphs have

a title summarizing variable relationship

axis labelled with variable names and units (independent usually on X)

scale with equal increments

averages used for dependent variable

line break with a =

how to interpret graphs

state what graph shows

identify trends or patterns

explain results scientifically

conclusion

support or disprove hypothesis

restate hypothesis

back up observations with two data figures

if disproven explain why

validity

degree to which you tested what you set out to test

accuracy

how close you are to the true value

precision

degree of detail the equipment allows

fairness

factors kept the same for a fair test

reliability

consistency of results - can be improved by:

repetition - experimenter conducts more trials

replication - someone else replicated experiment

sample size - larger number in experimental group

human error

mistakes that can be avoided with taking care

random error

unpredictable, i.e: precision, impact can be reduced with averages

systematic error

experiments design, have to change procedure or equipment