Measuring the Length of a Room

# Objective

To measure the length of your classroom by counting the number of steps and to express the length in cm/m.

# Theory

Measurement means the comparison of an unknown quantity with some known quantity. This known fixed quantity is called a unit. The result of a measurement is expressed in two parts. One part is a number. The other part is the unit of the measurement. For example, if you measure the length of the room using your foot and the length of the room is found to be 12 lengths of your foot, then 12 is the number and 'foot length' is the unit selected for the measurement.

Measurement plays a crucial role in our daily lives. When we buy things in a store, we usually say that we need 1 kg of apple, 5 m of cloth, etc. That is we need to quantify things. If you walk into the store and say, "I need some sugar," the amount of sugar you have in your mind may not be the same as what the store owner understands. Now, let us assume you say “I need a handful of sugar.” But even now, the amount of sugar you can hold in your hand will not be the same as the amount the shopkeeper can hold in his hand. If instead you say you need 1 kg of sugar, he will know exactly how much sugar to give. The kilogram used here is referred to as the standard unit; it will remain the same regardless of who measures it or where it is measured. That is we need a common set of units in measurement that is uniform and can be used by everyone. Such a system is called a standard of measurement. In contrast, a nonstandard unit of measurement is something that may vary in length or weight. For example, using a stick, block or foot to measure is unreliable because the length of each stick or block will be different. Likewise, a human foot cannot be used to measure length because everyone's foot is of distinct size.

In ancient times people developed unique methods of measurement with the tools which were available to them. It was usually associated with body parts such as hand span, foot length etc. To solve the issue of different measurements, a universal system of measurements known as the International System of Units (SI Units) was found and accepted. Scientists and other experts use the SI system to make measurements. In the SI system, length is measured in meters. Depending on the length to be measured, we can convert a meter into different units such as millimeters (mm), centimeters (cm) and kilometers (km). Likewise, the SI unit of weight is kilograms and time is seconds.

# Learning Outcomes

• Students can learn the concept of measurements.
• Students can get an idea of different methods used to measure length.
• Students can understand the importance of standard units of measurement.
• Students can learn to distinguish standard and non-standard units of measurement.