Analysis of the Earth and Environment Lecture 8: Units

Question 1

Define Physical quantities

Answer 1

Physical Quantities: Those quantities which can be measured and, are necessary to describe any physical phenomenon.

Question 2

Define and list the fundamental physical quantities

Answer 2

Fundamental physical quantities - Quantities which are
independent and do not depend on other quantities. Length (L),
Mass (M) and Time (T)

Question 3

Define Derived quantities

Answer 3

Derived quantities - Quantities which can be expressed in
terms of fundamental quantities. Force, Work, Area, volume
etc.

Quantities that are measured through an equation/ maths.

Question 4

What is the Systeme internationale

Answer 4

The SI, or metric system of units is the internationally
accepted system of units for measurement in the field of
sciences, including Environmental science, Geology and
Geography.

The SI units consists of base units and derived units

Question 5

List the base quantities and their symbols

Answer 5

Base Quantity SI Unit Symbol

Length Meter m
Mass Kilogram kg
Time Second s
Electric current Ampere A
Temperature Kelvin K
Luminous-
Intensity Candela cd
Amount of
substance mol mol

Question 6

Define Astronomical unit

Answer 6

astronomical unit(average
distance of sun from earth)

AU

1.496 X 1011 m

Question 7

What is scientific notation and the order of magnitude

Answer 7

All scientific quantities should be written as scientific notation, which employs powers of 10.
e.g.

Additionally in scientific notation the “3.56” number must be between 1 and 10.

3,560,000,000 = 3.56 x 10⁹ m

The order of magnitude is the number denoting the amount of the power of 10. For example in 3.56 x 10⁹, the order of magnitude is ⁹.

Question 8

What is 2.3×10⁴ in normal form

Answer 8

23000
Add 0s after first number, however include following numbers as 0s if present.

Question 9

Define Accuracy

Answer 9

Accuracy – how close a measurement comes to
the “true value”.

Like if someone throws a dart, the “ true value “ is the bullseye.

Question 10

Define precision

Answer 10

Precision – how close a series of
measurements are together.

Consistency in measurements

Question 11

What is percentage error and how do you calculate it

Answer 11

Percent error is used to estimate the accuracy of a measurement.

Percent error =

           True value then X100

= Percent error

Question 12

Define Significant figures

Answer 12

Zeros between non-zero digits are significant.

That is, 508 cm has 3
significant figures.

Leading zeroes merely locate the decimal point and are never
significant.

That is, 0.0497 cm equals
4.97 x 10⁻²cm and has 3
significant figures.

Trailing zeros are significant as follows: 50.0 mL has 3 significant
figures, 50. mL has 2 significant figures, and 50 mL has 1 significant figure.