2. Contents
Phenomena and illusions
Measuring length, mass, and time
Estimating quantities
Accuracy of measurement
Heat and temperature
3. Physics???
the branch of science concerned with the
nature and properties of matter and energy.
Matter?
with mass and size. Or occupies physical
space
Matter can exist in several states, also called
phases.
The three most common states are known
as solid, liquid and gas.
4. Phenomenon (phenomena
plural)
Scientific context that is observed or exist.
Phenomena is something that you perceive with
your senses
Ex: Natural phenomena which includes gravity,
tides, oscillations(movement back and forth in a
regular rhythm.)
Rocket launch
When rocket is launched you can see light and
hear sound
Which one reaches to your senses first?
5. Phenomena
Rocket Launch Example
You can see light first
Reason: Light travels faster than sound and in
straight lines (299 792 458 m / s) or 3x1010 m/s or
186 thousand miles in a second
Sound speed 343 m / s and it travel in wave form.
8. What do you meant by
measurement?
Comparing an unknown quantity with some known
quantity is called measurement.
Some physical quantities(anything which can
measurable ) are:
10. Arbitrary unit of measurement
Before the development of standard unit
people used arbitrary unit of measurement.
Some of them are still in use
Ex:
13. Standard unit of measurement
Why?
To maintain uniformity in measurement, SI
unit of measurement introduced.
Full form – International system of units
Most widely used system in the world
14. Result of measurement
Result of measurement has two parts; one is
number and another part is unit.
Ex: height of person is 60 cm
Here 60 is the number and unit is centimeter
15.
16.
17. Standard unit of measurement
It is based on MKS (Meter – Kilogram –
Second) system.
Length, Weight and Time are considered as
basic quantities of measurement and other
quantities are derived from them
also called as derived units.
19. Standard unit of measurement
Fundamental unit
Unit name Unit abbreviation Measurement
metre m distance
kilogram kg mass
second s time
ampere A electrical current
kelvin K temperature
mole mol number of particles
candela cd light intensity
20.
21. Derived Units
Derived quantity Name Symbol
Area Square meter m2
Volume Cubic meter m3
Speed, velocity Meter per second m/s
22. Velocity = that measures displacement (or
change in position, Δs) over the change in
time (Δt), represented by the equation v =
Δs/Δt.
Difference b/w distance and displacement?
video
23. Units of Length
kilometer km 1,000 m
hectometer hm 100 m
decameter dam 10 m
meter m 1 m
decimeter dm 0.1 m
centimeter cm 0.01 m
millimeter mm 0.001 m
Micrometer µm 0.000001m
Nanometer nm 0.000000001m
32. Accuracy
Accuracy depends up on measuring instrument and
its calibration.
Depends up on how well the scale on the instrument
has been constructed.
Depends on how well you use the measuring
instrument.
Care in setting up the device is needed
Example: A stopwatch the measure the time by
seconds can’t be used to measure the tenth of the
second.
33.
34. Heat & Temperature
A thermometer is a tool that measures
temperature — how hot or cold something is.
Thermometers are used to see if you have a
fever.
thermo (heat) and meter (measuring device)
Who invented the thermometer?
Galileo Galilei in 1593
In 1714, Gabriel Fahrenheit invented the
modern mercury thermometer.
35.
36.
37. Thermometer
Two liquids that are commonly used in
thermometer are mercury and alcohol.
Mercury freezing point -39 degree Celsius
Mercury boiling point 360 degree Celsius
Alcohol freezing point -112 degree Celsius
Alcohol boiling point 78 degree Celsius
39. In Celsius scale, the melting point of ice is
taken as 0 °C and the boiling point of water as
100 °C. The difference between the two points
is divided into 100 degrees.
In Fahrenheit scale, the lower fixed point or
the melting point of ice is 32 °F and the upper
fixed point or the boiling point of water is 212
°F. The difference between these two points is
divided into 180 degrees.
In Kelvin scale, 0 °C corresponds to 273 K
and 100 °C corresponds to 373 K.
Celsius scale and Fahrenheit scale:
42. answer: Digital thermometers contain a device
called a thermo resistor. The thermo resistor has
an electrical current running through it, and the
resistance, or how freely the current can flow,
changes with temperature. A small computer or
other circuit measures the resistance, and
converts it to a temperature. The temperature is
then displayed on the thermometer screen.
44. Work Assignment
1. Arrange the following lengths in their increasing
magnitude.
1 meter, 1 centimeter, 1kilometer , 1 millimeter
2. The height of a person is 1.65 meters. Express it
in cm and mm.
3. Why do we need standard unit of measurement?
4. Pg no.194- pg no 198
