Classification of Matter

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Fundamental Graph Drawing in Science

Why do we need graph in science?
*Scientific studies involve experiments and collection of data. Data are mere number and can not be used unless interpreted. Graphs are commonly used to interpret data.
*Graphs serve as visual aid to display clearly how two (or more) quantities are related each other in any experiments.
*Sometimes you have to accept uncertainties in experiments due to error in conducting experiments, these can be shown by graph drawing.

What should be found in a graph?
*The common used title is graph of (quantity) against (quantity)
*Basically, there are 2 axes (horizontal axis and vertical axis), it is a good practice to draw the 2 axes, 2 cm from the edge of the graph
Give label of the 2 axes as quantity / unit or quantity
unit
*Scale if necessary, it should be fives or tens.

What you should do
*Always begin from the origin (the point where you start your experiment) for example if you start your experiment at 400C then you have to begin at 400C, do not try to lengthen the line below 400C.
*One axis is for the independent variable, the other for the dependent variable.
*When you plot the graph, make the line or the curve pass through as many points as possible, and draw firmly, do not go over the line / curve again.



So what is gradient?
The value is the division of vertical side with the horizontal side (do not forget its unit).
Gradient will be the constant of the relation of the variables.
From the graph also, we can conclude that degree of X is degree of Fahrenheit, there are still many conclusion can we make by interpreting the graph.

Try below exercise :D

Measurement and Physical Quantities

Measurement is comparison of one thing with another thing that has already been a standard where an observation is needed. In physics, Measurement is ratio of one physical quantity with another physical quantity that has standard. Measurement is needed in our daily life but sometimes we don’t realize that we have already measured, for example: We know the tallest boy in the class or the most generous person in the school. We can say that almost all occupations need to measure such as a carpenter who will make a shelf or a table and an automotive designer who will make a good design of a car, etc.

Physical quantity is a quantity that can be measured. If it could not be measured, it was not a physical quantity such as sweetness, virtues (discipline, kindness, etc), beauty, wildness, etc. A physical quantity has a SI unit (System International unit). SI Unit is a unit that is accepted by whole countries in the world as a standard unit.

TWO KINDS OF PHYSICAL QUANTITIES
There are two kinds of physical quantities:
1)Base Physical quantities
This physical quantity is very basic and not derived from other physical quantities. There are 7 base physical quantities, as follow :

















2)Derived physical quantities
Derived physical quantities are quantities derived from base physical quantities. For example:

















STANDARD FORM NUMBERS


Sometimes we can find kind of number which is too long to write for example 1.000.000.000 to simplify we use standard form number as 10^9 or prefix as 1 Giga.
















There are some rules to use standard form number :
* The number should have more than two zeros or thousandth up. If it is still hundredth, we don’t need to convert into standard form. See examples below:
100 No need to convert into standard form number.
1.000 10^3
10.000 10^4
100.000 10^5
0,01 No need to convert into standard form number.
0,001 10^–3
0,0001 10^–4
*To convert usual numbers into standard form numbers, we must let the number between 1 - 10. There are two ways to convert according to the numbers, as follows:
a)if the number is more than 1
We count how many zeros that the number has or how many steps we moved the comma of the numbers. See examples below:
-1.000 has three zeros so that we can write as 10^3 in standard form number.
-10.000 = 10^4
-11.000 = 1,1 x 10^4
-27.000 = 2,7 x 10^4
-340.000= 3,4 x 10^5
b)if the number is less than 1
We count how many steps we moved the comma of the numbers. See examples below:
-0,001 = 10^–3
-0,0001 = 10^–4
-0,004 = 4 x 10^–3
-0,0007 = 7 x 10^–4
-0,0025 = 2,5 x 10^–3
*Operation in standard form numbers.
Multiplication
Add the power of the standard form numbers and multiply the numbers in front of the cross sign. For examples:
-10^3 x 10^4 = 10^(3 + 4) = 10^7
-2 x 10^3 x 3 x 10^4 = 2 x 3 x 10^(3 + 4) = 6 x 10^7
Division
Subtract the power of the standard form numbers and multiply the numbers in front of the cross sign. For examples:
-10^8 : 10^3 = 10^(8 - 3) = 10^5
-(8 x 10^9) : (2 x 10^6) = 4 x 10^(9 - 6) = 4 x 10^3