1. MEASUREMENT
We obtain an understanding of our environment by observing the physical world through measurements.
Measurement is a comparison of physical quantity with a standard unit.

2. MEASUREMENT It is expressed with numbers and units.
Physical characteristics can be expressed in terms of fundamental quantities.
Our comprehension of the physical world is based on fundamental quantities.

3. FUNDAMENTAL QUANTITIES
Four quantities have been identified and specified as
fundamental.
These are:
Length
Mass
Time
Electric charge
They form the basis for other quantities
necessary to describe and understand the
physical sciences.

4. Length We use length to measure location or size.
Length is defined as the measurement of space in any direction.
Note: Space has three dimensions, each is measured by length.
Consider a box:
Length (l)
Width (w)
Height (h)

5. Time Time is the continuous forward flow of events.
Events allow us to precise time, without events, we have no innate awareness of time.

6. Mass Mass quantifies matter.
Mass refers to the amount of matter an object contains.

7. Electric Charge
Electric Charge is the property associated with some particles, that gives rise to electric forces and electrical phenomena.

8. STANDARD UNITS
A standard unit is a fixed and reproducible value for the purpose of taking accurate measurements.
A set of standard units is referred to as a system of units.

9. British System British System uses the familiar unit of: Length: foot
Mass: Slug
Weight: pound
Time: Second
Electric Charge: Coulomb
Note: It is also called the Gravitational System of Units.

10. Metric System Metric System is considered to be simpler
than the British System as the conversion is by a
factor of ten.
The standard units of:
Length – meter, m
Mass – kilogram, kg
Time – seconds, s
Electric Charge: Coulomb
They are called the International System of Units (SI
units).

11. Systems of units Metric System Length – meter, m Mass – kilogram, kg
Time – seconds, s
Electric Charge - Coulomb
British System
Length: foot
Mass: Slug
Time: Second
Electric Charge: Coulomb
Weight: pound

12. International System of Units
There are seven base units of the International
System of Units.
Meter, m, measures length.
Kilogram, kg, measures mass.
Second, s, measures time.
Ampere, A, measures electric current.
Kelvin, K, measures temperature.
Mole, mol, measures amount of substance.
Candela, cd, measures luminous intensity.

13. Derived Quantities
Derived Quantities are formed by combining two or more of the fundamental quantities.
Examples:
Area = length x width
Volume = length x width x height
Speed = distance/time
Density = mass/volume

14. Density Density refers to how compact or crowded a
substance is, that is, the amount of mass
located in a definite volume.
Density is simply the mass per unit volume.
Density = mass/volume

15. Measurement Errors Systematic Errors:
Systematic errors are associated with instruments or the technique used.
They are as a result of:
Improperly calibrated instrument
Error incurred from observer’s reading

16. Measurement Errors Random Errors:
Random Errors result from unknown and unpredictable variations in experimental situations.
Such as fluctuation in electrical voltage.
Changes in temperature, pressure, etc

17. Accuracy / Precision
Accuracy indicates how close measurement comes to the true value.
Precision refers to the agreement among repeated measurement, that is, how close they are together.

18. Converting Quantities
Use a conversion factor, a ratio relating
one unit to another.
Choose the appropriate form of the conversion factor(s) so that the unwanted units cancel.
3. Check to see that the unit cancel and that
you obtain the desired unit.

19. Converting Quantities
Desired quantity and units = given
quantity and units x conversion factor

20. Common relationships 1 kg = 2.2 lbs. 1 lb. = 453.6 g 1 inch = 2.54 cm
1.06 qt = 1 L
1.0 mile = km

21. Temperature A measure of hotness or coldness of an object .
Types of temperature scales:
Fahrenheit: on this scale the normal freezing and boiling points of water are taken to be 32F and 212F respectively.
Celsius: Boiling point is 100C and the freezing point is 0C

22. 0ºC = 32ºF
32ºF
0ºC

23. 100ºC = 212ºF
0ºC = 32ºF
0ºC
100ºC
212ºF
32ºF

24. Relationship Between oC and oF
oF = 1.8 oC + 32
There is no direct relationship between K
and oF. Therefore, one must go through oC
in order to get temperature in K.
K = oC