STD IX – MEASUREMENT AND EXPERIMENTATION – (Online)

MEASUREMENT

Systems of unit and units in S.I system

The International System of Units (Système international d’unités) abbreviated as SI,  is the modern form of the metric system and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units. The system also establishes a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units.

In this topic, you will learn some important definitions and terms related to measurement, fundamental and derived units, and some units of measure.

EXPERIMENTATION

Measurement of length

If you have seen athletes running the 100-metre dash in the Olympics or any other track and field event, you will have noticed that even a nano-second counts. Timing and speed are everything for an athlete to be the first to reach the finishing line. To compare performances of different athletes, three different quantities are measured, distance, time and speed.

While the distance is already laid down on the track using a tape, time is measured using a stopwatch and speed is measured by devices like radar guns. At home, you can use devices made for individual use like your phones, pedometers, fitness trackers etc to measure speed, distance and time if you are going running or walking.

Similarly, there are many other quantities that need to be measured in everyday lives. For example, the speed of a car, the weight of fruits and vegetables consumed in your home, the amount of sugar in coffee, the correct amount of chemicals required in an experiment, the amount of fuel required by an aeroplane, etc.

Measurement of length of an object using Vernier callipers

Vernier Callipers | Principle of Vernier | Use of Vernier | Least Count of Vernier Callipers

Screw Gauge | Principle of Screw | Least Count of a Screw Gauge | Zero error in screw gauge

Measurement of time and simple pendulum

How much sugar is needed to bake a cake? How much space will the car occupy in the garage? How much luggage is allowed by your airline? In how much time can you finish writing the exam? Here are some instances that require you to measure weight and time.

Every object has a mass that needs to be measured accurately if you want to put it into use. For example, a weighing scale or balance is used to measure different kinds of weights.

Shopkeepers use the grocer’s balance, vegetable vendors use a beam balance, you can check your weight with the bathroom scales etc, although all these traditional balances have slowly been replaced by electronic weighing scales that measure different weights.