Unit Prefixes

Here are some examples of the use of prefixes:

• 70 000 m can be written as 70 km (kilometre)

• 0, 001 g is the same as 1 × 10^−3 g and can be written as 1 mg (milligram)

• 2, 6 × 10^6 N can be written as 2, 6 MN (meganewton)

Average Speed and Average Velocity

Average Speed is the ration of distance per unit time.

• Speed is always positive.
• In the SI system, the unit of speed is the meter per second (m/s)
• In practice, the speed of automobiles, aircraft, and other everyday objects is ofteneasured in kilometers per hour (km/h):

Average Velocity is the ratio of the change of position and the time interval.

is also written as:

• In the SI system, the unit of speed is the meter per second (m/s)
•  Velocity can be positive or negative. A negative velocity refers to motion in the negative direction for the coordinate axis chosen.
• We cannot tell the velocity is positive or negative until the direction at the x-axis is specified.

Newton's Law of Motion (Law of Dynamics)

• 1st Law, Law of Inertia: In the absence of a net force, a body at rest remains at rest and a body in motion will continue in motion at constant velocity 
• 2nd Law, Law  of Acceleration: When a net force acts on a body, it will be accelerated in the direction of the force with an acceleration directly proportional to the mass. (equation of motion)
• 3rd Law, Law of Interaction: When a body exerts a force on another body, the 2nd body exerts a force on the 1st body of the same magnitude but in the opposite direction.

MULTIPLES AND SUBMULTIPLES OF THE METER

kilometer (klick) - 1 km - 103 m
meter - 1 m
centimeter - 1 cm - 10 2 m
millimeter 1 mm 10 3 m
micrometer (micron) 1 m 10 6 m
nanometer 1 nm 10 9 m
angstrom 1 Å 10 10 m
picometer 1 pm 10 12 m
femtometer (fermi) 1 fm 10 15 m

Greek Alphabet

What is the importance of wiping the ice before introducing it to water in the calorimeter?

The specific heat of water is different from the specific heat of ice and also of wet ice. If the ice is not wipe before introducing into a calorimeter experiment it can increase the mass of water in the calorimeter and become source of inaccuracy.

Atoms

Atoms are the smallest particles of  matter. Atoms cannot be divided into smaller parts without changing their  properties. Atoms have a nucleus surrounded by a cloud of electrons. 

An atom consists of a tiny dense nucleus surrounded by electrons that are spread throughout a relatively large volume of space around the nucleus. The nucleus contains positively charged protons and neutral neutrons, so it is positively charged. The electrons are negatively charged. Because the amount of positive charge on a proton equals the amount of negative charge on an electron, a neutral atom has an equal number

of protons and electrons. Atoms can gain electrons and thereby become negatively

charged, or they can lose electrons and become positively charged. However, the number

of protons in an atom does not change.

Protons and neutrons have approximately the same mass and are about 1800 times

more massive than an electron. This means that most of the mass of an atom is in its

nucleus. However, most of the volume of an atom is occupied by its electrons, and that

is where our focus will be because it is the electrons that form chemical bonds.

Matter

Matter is anything that occupies space and has mass. Example, wood, plates, clothes, shoes, etc.

Classification of Matter
a. Pure Substance
     i. Element - the simplest pure substance
                     - composed of only one kind of material
                     - ex. silver, iron, aluminum
    ii. Compound - consists of two or more elements always in the same proportion
                          - can be separated into simpler substances by chemical means
                          - ex. salt, water
 b. Mixtures - two or more types of substances
                   - variable composition, can be separated by physical mean
    i. Homogeneous - the composition is uniform throughout the sample
                              - ex. air, salt water
    ii. Heterogenous - nonuniform composition
                              - ex. pizza, water and sand

States of Matter
a. Solid - has both distinct shape and definite volume
            - atoms are arranged orderly
b. Liquid - has a distinct volume but dependent of its container that is occupies
c. Gas - does not have definite shape or volume
           - particles are far apart, there's only little attraction
           - conforms to the volume and shape of it's container

Properties of Matter
a. Physical Property - a characteristic of the substance that can be observed/measured, such as color, shape, odor, luster, size, melting/boiling point and density
b. Chemical Property - a characteristic that indicates the ability of a substance to form another substance, this cannot be determined just by observing or touching the substance,
                                 - ex. Heat Combustion
c. Intensive Property - a property of matter that is dependent of the quantity of the substance but depends on the kind of matter
                                - ex. Density, boiling and melting point, specific gravity
d. Extensive Property - depends of quantity of a substance
                                 - ex. Mass, Volume

Changes of Matter
a. Physical Change - a change in physical property that retains the identity of the substance: a change in size, or a change in shape or in appearance or state
                               ex. water boiling, water freezing, sugar dissolving in water
b. Chemical Change - a change in which the original substance is converted to one or more new substances
                                - ex. paper burns, iron rusts, silver tarnishes

Elements of Scientific Method

1. Observations and measurements (quantitative data).
2. Hypothesis. A possible explanation for the observations—in other words, a tentative answer or an educated guess.
3. Experiments. The testing of a hypothesis under controlled conditions to see whether the test results confirm the hypothetical assumptions, can be duplicated, and are consistent. If not, more observations and measurements may be needed.
4. Theory. If a hypothesis passes enough experimental tests and generates new predictions that also prove correct, it takes on the status of a theory, a well-tested explanation of observed natural phenomena. (Even theories may be debated by scientists until experimental evidence decides the debate. If a theory does not withstand continued experimentation, then it must be modified, rejected, or replaced by a new theory.)
5.  Law. If a theory has withstood the test of many well-designed, valid experiments and there is great regularity in the results, that theory may be accepted by scientists as a law. This is a concise statement in words or mathematical equations that describes a fundamental relationship of nature. Scientific laws are somewhat analogous to legal laws, which may be repealed or modified if inconsistencies are later discovered. Unlike legal laws, however, scientific laws are meant not to regulate but to describe.

Science and its branches

Science (from the Latin scientia, meaning “knowledge”) - is an organized body of knowledge about the natural universe and the processes by which that knowledge is acquired and tested.

1. Social Sciences - deal with human society and individual relationships

1. Natural Sciences - investigate the natural universe.

• Biological Science (also called "Life Science") - the study of living matter
• Physical Science - the study of nonliving matter.

5 Major Divisions of Physical Science

• Physics, the most fundamental of the divisions, is concerned with the basic principles and concepts of matter and energy.
• Chemistry deals with the composition, structure, and reactions of matter.
• Astronomy is the study of the universe, which is the totality of all matter, energy, space, and time.
• Meteorology is the study of the atmosphere, from the surface of the Earth to where it
• ends in outer space.
• Geology is the science of the planet Earth—its composition, structure, processes, and history.

Happening this afternoon at Dumaguete City. Let's get involved! Lets make a difference!

I don't know what am I going to do with my life. :(
So much problems!