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

Theory LawA 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

(cm3)

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 0.917 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--0.01 • Milli—Milk—m--0.001

Practice

1. 7.09 g to _________ kg

2. 5.0 mL to ________ L

3. 3.2 km to ________ mm

4. 0.054 L to ________ mL

5. 67.5 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/

Manipulated variable– Cause

• Y-axis– Vertical Axis– Dependent/

Responding 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