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1.2 Physical measurements

A student measured Understanding experimentation
the length of an object When people began to explore the world, they first made observations
using 3 different of physical phenomena. But if you only observe, it is impossible to get

rulers. What are the precise answers about why something happens. People then started
differences between to make purposeful observations and record them. They then began
to perform experiments, to reproduce and test their observations in a
these 3 types of
systematic way.
measurement?
ACT Why do we perform and repeat experiments in science? What can
you say about a claim that cannot be observed and/or tested? What do
1 you understand by the word systematic?
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Measurements in Physics
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0 CM 1 2 3 4 5 6 7 28 29 30 In order to conduct experiments, you should carry out different
measurements of the phenomena you are interested in. Measurements
3 are carried out by means of scientific instruments designed to
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measure specific things. Most measurement devices have their own
scale that helps quantify a physical quantity.

ACT Look at the images. What is:
A thermometer (a scientific
A textbooks nis edu kz
a) the name of each instrument? instrument to measure
temperature) has a scale.
b) the physical quantity it is measuring?
This scale has divisions
indicated by marks.

Units of measurement of quantities
Scientists have assigned units to physical quantities to carry out
B
measurements and make better calculations. A physical quantity
is a quantity that describes properties of a physical body or physical
phenomena, and can be measured using instruments as well as
calculated using specific formulas. Each physical quantity has its own
symbol and a unit of measurement.
C
REMEMBER! The International System of Units (SI units) was established
to standardize measurements and calculations across the sciences. Each
unit has a corresponding standardized symbol.

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