Scientific Investigations

Science Fusion – Holt McDougalSciencesaurus – Great Source Education Group

Testable (scientifically testable) ––A term used to describe a question that can be answered through an experiment or observation.

An organized scientific study of the natural world that may include making systematic observations, asking questions, gathering information, analyzing data, summarizing results, drawing conclusions, and/or communicating results.

Investigation

A scientific test or procedure that is carried out under controlled conditions to answer a scientific question.

Experiment

Controlled variable—A factor or condition in a scientific experiment that is purposefully kept the same.

•There are experiments that can be done in the field, but fewer conditions can be controlled.

•Sometimes discoveries can be made without conducting experiments.

Observation––Information about the natural world gathered through the senses and/or scientific instruments.

Inference- logical explanation of an observation that is drawn from prior knowledge

Hypothesis––A statement that can be tested scientifically through experiments and/or other scientific investigations.

•A hypothesis can be tested through an experiment or investigation.

•Variable—An event, condition, or factor that can be changed or controlled in order to study or test a hypothesis in a scientific experiment.

Test variable (independent variable)—The variable manipulated by the experimenter in order to study changes in the outcome variable.

•The hypothesis will identify the test variable.

•A simple experiment should have one test variable; all other variables should remain constant so that they do not affect the results.

•The hypothesis is tested by measuring the outcome variable.

•Outcome variable (dependent variable)—A factor, usually being measured or observed, that responds to, or depends on, another factor (test variable).

Control group—A group in a scientific experiment that serves as a reference for comparison to the experimental group; a group that is untreated by the factor being tested.

•Data is gathered through observation or experimentation.

•Everything that occurs needs to be recorded as well as the set up and procedures of an experiment.

•Data is analyzed to determine the relationship between the test and outcome variables.

•Then conclusions can be drawn and a determination made whether the data supports the hypothesis.

Scientific Study• Defining a problem• Forming a hypothesis and making a

prediction• Planning an investigation• Identifying variables• Collecting and organizing data• Interpreting data and analyzing

information• Drawing and defending conclusions.

•Data/Results should be verified through repetition and replication.

Repetition versus Replication•Repetition—Making multiple sets of measurements or observations in a scientific investigation.

•Repetition is when an activity is repeated by the same person(s).

Repetition versus Replication•Replication—The reproduction of a scientific investigation by another person to ensure accuracy.

•Replication is when an activity is reproduced (or copied) by a different person(s).

Scientists and researchers verify results through repetition and replication to ensure accuracy and reliability.

• Inference- a logical explanation of an observation that is drawn from prior knowledge (knowledge you already have) or experience

• In the SI system, the prefixes identify the size of the unit

• Mean- Average of the data• Median- number that is in the middle

of a set of data• Mode- the number that appears most

often in a set of data• Range- the difference between the

largest and smallest numbers in a data set

Validity and Reliability Neither Valid nor Reliable

Reliable but not Valid

Valid & Reliable

Fairly Valid but not very Reliable

Think in terms of ‘the purpose of tests’ and the ‘consistency’ with which the purpose is fulfilled/met