Introduction to Physical Science

What is Science? Is a system of knowledge and the methods you use to find that knowledge Science begins with curiosity and often ends with discovery

What is Physical Science Covers a broad range of study that focuses on non-living things –Two Branches: Chemistry and Physics Chemistry—is the study of the composition, structure, properties and reactions of matter Physics—is the study of matter and energy and the interactions between the two through forces and motion

Scientific Method An organized plan for gathering, organizing and communicating information The goal of any scientific method is to solve a problem or to better understand an observed event

Steps in the Scientific Method 1.Problem/Question  what you want to know 2.Research  gather information about the question 3.Hypothesis  is a proposed answer to the question or educated guess

Steps in the Scientific Method 4. Perform an Experiment  test the hypothesis 5. Analysis of Data 6. Conclusion

Parts of an Experiment Trial  repeating the experiment Variable  any factor that can change in an experiement –Independent/Manipulated  factor you change –Dependent/Responding  factor that changes as a result of the independent/manipulated variable

Parts of an Experiment Constant  factors that does not change Controlled experiment  is an experiment in which one variable is deliberately changed at a time

Theory verse Law TheoryLaw  A well-tested explanation for set of observations  not widely accepted  Can be proven wrong  Is a statement that summarizes a pattern found in nature  widely accepted  99% true

Measurement SI UNITS –SI = Standard International –By adhering to one system of units, scientists can readily interpret one another’s measurements

Measurement—Length The straight line distance between two points SI unit: meter (m) Tools: meter stick or ruler

Measurement—Mass How much matter is in an object SI Unit: kilogram (kg) Tools: balances, electric scales, spring scales

Measurement—Temperature Amount of heat given off by an object SI unit: Kelvin (K) Tool: thermometer

Measurement—Volume Amount of space an object takes up Volume of a liquid –Use a graduated cylinder –Unit: liter (L) Volume of Regular Object (a block) –Use a ruler (LxWxH) –Unit: cubic centimeters (cm 3 )

Measurement—Volume Volume of Irregular Solid (a rock) –Use water displacement: the difference in water level when something is placed in a graduated cylinder –Unit: liter (L)

Density Density = mass / volume Units: g/mL or g/cm3 Density of Water = 1g/mL Any object’s density greater than water will sink Any object’s density less than water will float

Density Practice 1.What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3? 2.A piece of wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0 grams. What is the density of the wood? Would the piece of wood float in water?

Density Problems 3.The density of aluminum is 2.70 g/mL. If the mass of a piece of aluminum is 244 grams, what is the volume of the aluminum? 4.An ice cube measuring 5.80 cm by 5.80 cm by 5.80 cm has a density of g/mL. What is the mass?

Conversions within The Metric System King Henry Died By Drinking Chocolate Milk Kilo—King—k--1,000 Hecto—Henry—H—100 Deka—Died—dK—10 Base—By--m,L,g Deci—Drinking—d--0.1 Centi—Chocolate—c Milli—Milk—m

Practice g to _________ kg mL to ________ L km to ________ mm L to ________ mL kg to ________ g

Data Information gathered from experiments Qualitative –Data in forms of words –Usually observations –Ex: The floor is made of tile Quantitative –Data in forms of numbers –Ex: Jim jumps 5 meters in the air

Graphs Parts X-axis –Horizontal Axis –Independent/Manipulat ed variable –Cause Y-axis –Vertical Axis –Dependent/Respondin g variable –Effect

Types of Graphs Line Graph –Useful for showing changes that occur in related variable (ex: time) –Direct proportion—as one variable increase the other variable increases as well –Inverse proportion—as one variable increase the other variable decrease –Constant graph—as one variable increases the other variable stays the same

Types of Graphs Bar Graph –Often used to compare a set of measurements, amounts or changes Circle Graph –Is a divided circle that shows how a part or share of something relates to the whole