Defining Physical Science

Defining Physical Science:

Physical Science:

The study of matter and energy

A merging of two major braches of Science:

1. Chemistry: Study of the composition

and changes of matter

2. Physics: Study of energy and laws of

motion (i.e. the behavior of matter)

Advances in Physical Science:

Advances first stem from a need,

followed by inquiry.

Science is the investigation of rational

concepts capable of being tested by

observation and experimentation.

This analytical method distinguishes

science from all other disciplines.

Advances in Physical Science:

Scientists: Question natural

phenomenon

Observe the world around them.

Read a variety of scientific books.

Become science teachers.

You are a scientist if you do any of these!

Advances in Physical Science:

Basic Assumptions of Science:

There is order in the universe.

The human mind is capable of

understanding it.

Natural phenomenon is testable by

experimentation that is repeatable.

A real Scientist will attempt to answer

their questions.

Scientific Method:

• The Scientific Method: A systematic

approach to problem solving.

1. State the problem: Must first define the

problem based on observation of a need.

2. Gather information on the problem: -- “

Leave no stones unturned”– The problem

may already be solved…at least partially.

Scientific Method:

3. Form A Hypothesis: A plausible prediction of the

outcome of experimenting.

- Use deductive reasoning (if/then statement)

- e.g. If I use a fuel additive in my car, then

it should improve its mileage.

- Hypothesis are often stated as a question.

Scientific Method:

4. Experiment: Test the Hypothesis

-Variable: One factor being tested.

-Data: Information outcome of the experiment.

Types of Data:

1. Quantitative: Numerical Data

2. Qualitative: Descriptive Data (color, behavior, etc)

Scientific Method:

Must use a control set-up and experimental set-up.

-The experimental set-up contains the

variable to be tested, the control does not.

-The control is the standard for comparison.

Scientific Method:

5. Record and Analyze data:

-Use Accurate Measurements

6. State Conclusions:

-Only after the experiment has been

repeated to insure accuracy.

Scientific Method: Theory:

The most logical explanation of events occuring in

nature.

Developed through repeated tests.

Law:

A repeatedly tested theory..

Generally accepted as true, but may be modified

after further discoveries.

Fact:

The absolute truth.

Scientific Method In Practice:

1. The problem: A need to lower the

freezing point of H2O to -10°C.

2. Information on the Problem:

-H2O freezes at 0°C

-Ethylene glycol freezes at -30°C

3. Hypothesis: One part ethylene glycol to

10 parts H2O will lower the freezing

point to -10°C.

Scientific Method In Practice:

4. Experiment:

Set up 6 replications of 1:10 ethylene glycol and

H2O mixtures.

Decrease Temperature.

Scientific Method In Practice: 5. Record and Analyze Data

Control: Experiment:

H2O C H2O w/ 1/10 Ethylene Glycol

0 -4

0 -3

0 -2

0 -3

0 -4

0 -2

X= 0 -3°C

Data or

Data Set

Scientific Method In Practice:

6. Conclusion: The freezing point of H2O

with 1/10 ethylene glycol is -3°C.

• Caution: Never test more than one

variable at a time.

• Use graphs to ease in interpreting data.

Time of Freezing of H2O with 1/10

Ethylene glycol (antifreeze)

Time (min) Temp °C

0 25

10 22

20 19

30 12

40 5

50 0

60 -3

-5

0

5

10

15

20

25

0 10 20 30 40 50 60

Time (min)

Te

mp

era

ture

(C

)

Temp

*Spaces between intervals on a graph must be equal.

Q: Does this graph represent the control or experimental set-up?

Scientific Terms:

Q: What does converge mean?

A: Come Together

Q: How would the temperature of a

reacting substance be affected in an

endothermic reaction?

A: Temperature would go opposite of

exothermic.

Scientific Measurements:

Measurements must be accurate,

reliable, and appropriate to the subject

measured.

Scientists use the metric or SI System

(Système International d’Unités).

Scientific Measurements:

Derived Units Volume: Liter

Weight: Newton

Density: Gram/Liter

Temperature: Celsius

SI Base Units

Scientific Measurements:

Length: Measure of distance

1 meter = 39.4 inches ( about 1 yard)

= 100 centimeters

= 1000 millimeteres

1000 meters = 1 kilometer

Common tools for measuring length

Meter Stick

Metric Ruler

Metric Tape

Rolotape

Scientific Measurements:

Prefix Symbol Multiplier Exponential

yotta Y 1,000,000,000,000,000,000,000,000 1024

zetta Z 1,000,000,000,000,000,000,000 1021

exa E 1,000,000,000,000,000,000 1018

peta P 1,000,000,000,000,000 1015

tera T 1,000,000,000,000 1012

giga G 1,000,000,000 109

mega M 1,000,000 106

kilo k 1,000 103

hecto h 100 102

deca da 10 101

1 100

deci d 0.1 10¯1

centi c 0.01 10¯2

milli m 0.001 10¯3

micro µ 0.000001 10¯6

nano n 0.000000001 10¯9

pico p 0.000000000001 10¯12

femto f 0.000000000000001 10¯15

atto a 0.000000000000000001 10¯18

zepto z 0.000000000000000000001 10¯21

yocto y 0.000000000000000000000001 10¯24

Metric prefixes, symbols, and multipliers

Scientific Measurments:

Volume: Amount of space an object takes up

Basic Unit: Liter (L) or Cubic Centimeter (cc or cm3)

Liters are usually used to measure liquid volume.

cm3 is usually used to measure solids.

○ e.g. The volume of a box can be measured by

length x width x heigth

○ 1 cm3 = 1 milliliter (1/1000 liter)

Scientific Measurments:

How could you measure the volume of an irregular shaped object in liters?

Liquid volume is measured using a graduated cylinder.

Measurements are read at the bottom of the meniscus (curved surface)

Bottom of Meniscus

Scientific Measurement:

Mass: The amount of matter in an object.

Basic Unit: Kilogram (1000 grams)

Mass is usually measured using a triple beam

balance.

Note: Mass is not the same as weight.

Scientific Measurements:

Density: The amount of mass in a given

volume of an object.

Density may be affected by:

1. Air trapped in the object.

2. Temperature of an object.

Scientific Measurements:

Density = Mass per unit volume of a

substance

Calculated by:

Density = mass divided by volume

Water density – 1 g/mL

d= m

V

Scientific Measurements:

Q: If wood floats in water, is its density

greater than or less than one?

Scientific Measurements:

Temperature: The amount of heat in an object

Basic Unit: Kelvin (K) Derived Unit: Celsius (C)

0 C = Freezing point of water

100 C = Boiling Point of water

Body Temp: 37 C

Room Temp: 21C

Measured using a thermometer (usually alcohol)

Scientific Measurements:

To convert temperatures:

K = C + 273

C = K -273

F = 9/5(C + 32)

C = 5/9(F − 32)

Dimensional Analysis:

Dimensional Analysis (DA): Method of

converting one unit to another

Uses a conversion factor- a factor that is

always equal to one

e.g. 1000 grams 1 or 1kilogram 1

1 kilogram 1000grams

Dimensional Analysis:

Convert 1350 grams to kilograms

1350 grams x 1 kilogram

1 1000grams

Cancel grams and multiply.

1350 x 1 kilogram = 1350 kg =1.35kg

1 1000 1000

Lab Safety:

Never do anything until you are

instructed.

Wear safety glasses in the lab when

you:

Use fire of any kind.

Handle hot glass.

Measure, mix or pour hot chemicals.