Ms. Hirsh Physical Science What is Science? Ms. Hirsh Physical Science

Scientific Method (5 Steps) An organized plan for gathering, organizing and communicating information Used to solve a problem or better understand an observed event Observation/Question  Hypothesis  Controlled Experiment  Data Collection  Conclusion

Parts to a Good Experiment Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged or controlled Controlled Experiment – Only 1 variable Control – the factors in an experiment that remain the same and do not change Variable – the factors in a experiment that change. A good experiment only contains 1 variable Manipulated Variable – Variable that deliberately changes Responding Variable – Variable that changes in response to the manipulated variable

Example Experiment Plants grow best under green light 10 basil plants are started from the seed and grown under various types of light 5 are grown under white light and 5 are grown under green light After several weeks the plants are measured and the average height of the plants are recorded What is the variable (the part of the experiment that changes)? Variable – green light Manipulating variable – green light Responding variable - plant growth What is the control (the parts of the experiment that are kept the same)? Control – white light, # and type of plants, amount of water, sunlight, temperature, ect.

Theory verse Law As evidence from an investigation builds up, a hypothesis may become so supported that scientists consider it a theory Hypothesis – scientific testable explanation for an observation or phenomenon Theory – Well tested explanation for a set of observations Subject to change, may be revised Never proved, only disproved Widely accepted by scientific community Law – Statement that summarizes a pattern in nature Law states how something will behave and a theory explains how it works ***REMEMBER*** theories and laws are not absolute, science is always subject to change

Branches of Science Chemistry – composition, structure, properties and reactions of matter Physics – matter and energy and interactions between the two through forces and motion Geology – origin, history and structure of earth Astronomy – universe beyond earth Biology – origin and behavior of living things Physical science – physics and chemistry