Scientific MethodLab Safety

What is Forensic Science?

• is the application of a broad spectrum of sciences to answer questions of interest to a legal system. This may be in relation to a crime or a civil action.

• Forensic science has shaped the world of justice, fuelling crime investigations and signifying the progress of modern technology.

The methods of Scientific The methods of Scientific studystudy

• Scientists use controlled experiments to obtain data that either do or do not support a hypothesis. By publishing the results & conclusions of an experiment, a scientist allows others to try to verify the results. Repeated verification over time leads to the development of a theory.

                           

The Scientific MethodThe Scientific Method• Scientific methods are used by scientists to

answer questions or solve problems. – Observations (ask ? & research background)– Make hypothesis– Design experiment– Implement experiment– Collect & analyze data– Draw conclusions (prove or disprove hypothesis)– Publish results

Designing a valid experimentDesigning a valid experiment

• Hypothesis

• Control

• Independent Variable

• Dependent Variable

• Data

HypothesisHypothesis

• An explanation for a question or a problem that can be formally be tested.

• It must be written as a testable statement.

• It needs to be specific & measurable

ControlControl

• The group in which all conditions are kept the same.

• Used to compare an experimental group against. (experimental group changes just 1 thing, ex. Amount of water given to plants)

Independent VariableIndependent Variable

• In an experiment only one condition is changed at a time. The condition that is changed is the independent variable.

• Ex. How much water a plant is given

Dependent VariableDependent Variable

• In an experiment scientists observe and measure changes that result from the independent variable. These changes are dependent on what happened in the experiment.

• Ex. How much plant growth was there based on amount of water given.

DataData• Information gained in a scientific

investigation

• Data is sometimes called experimental results

• Often in numerical form.

TheoryTheory

• A hypothesis that is supported by a large body of scientific evidence.

• By 1839 many scientific observation supported the hypothesis that cells are fundamental to life, so it became a theory.

Nature of ScienceNature of Science

• Scientists do their work in laboratories & in

the field. They collect both quantitative &

qualitative data from their experiments and

investigations.

QuantitativeQuantitative

• Numerically collected data.

• Experiments that result in information that can be counted or measured.

• Measured in SI (metric)

SI- International System of Measurement

• Scientific measurement used. It is a decimal system based on tens or portions of tens.

• Ex. Meter for length, Grams for mass, Liter for volume, Celsius degrees for temperature & Seconds for time.

Qualitative DataQualitative Data

Purely observational data. (describe in words or illustrations)

Useful because some experiments are not easily expressed by numbers.

Lab SafetyLab Safety

You must follow all guidelines You must follow all guidelines and instructions to ensure lab and instructions to ensure lab

safety! safety!

                                                                                      

Scientific Safety SymbolsScientific Safety Symbols