Module 1 - Measurement in Science

The process of determining the size, quantity, or extent of something using a standard unit.

Parts of the human body used for measuring length, like the span, cubit, and foot. They are not very accurate and vary from person to person.

Ancient systems of measurement used across different regions of the world, like the Indian system (using units like the danda, hasta, and angul), the Egyptian system, and the Roman system.

The need for a consistent and unified system of units that can be understood and used globally. It allows for accurate communication and comparison of measurements across different regions and fields.

Fundamental units in a system of measurement that are independent of other units. Examples are meter (m) for length, kilogram (kg) for mass, and second (s) for time.

Units derived from the combination of base units. Examples are area (m²) derived from length (m), volume (m³) derived from length (m), speed (m/s) derived from length (m) and time (s).

Prefixes added to the base units to represent multiples or fractions of the base units. Examples are kilo (k) for 1000, milli (m) for 0.001, and micro (µ) for 0.000001.

A standard quantity used to express the magnitude of a physical quantity.

A numerical value representing the size or amount of a measured quantity.

A physical quantity that can be measured, such as length, mass, time, or temperature.

The difference between the true value of a measurement and the measured value.

A standardized system of units used for measurement, such as the metric system or the imperial system.

The set of all possible values of a measurable quantity.

Accurate measurement is crucial in daily life and scientific research, ensuring clarity and preventing conflicts.

Measurement plays a vital role in scientific and technological advancements, enabling us to understand the world around us and create solutions.

Units based on body parts are unreliable because they vary from person to person. This causes inconsistencies in measurements and creates difficulties in trade and daily transactions.

The need for a consistent and universally accepted standard of measurement was recognized due to the limitations of body part units.

The Egyptians established a standard unit called the 'cubit', which was defined as the distance between the elbow and the tip of the middle finger of the ruling Pharaoh.

Standard cubit sticks were created, ensuring a consistent reference point for all Egyptians.

The British king Henry I established the 'yard' as the distance from his nose to his outstretched thumb.

Queen Elizabeth I defined a 'mile' as eight 'furlongs,' with a furlong being the distance an ox team could plow without stopping.

These standards proved helpful but were short-lived, since they were linked to individual rulers and changed when they were replaced.

The need for a stable and enduring system of measurement prompted the development of standardized units that are independent of individual rulers.

A physical quantity that can be measured.

Units are standard quantities used to measure physical quantities.

A system of units based on the meter, kilogram, and second. Used worldwide for trade and science.

The seven fundamental units in the SI system, from which other units are derived.

The base unit for length in the SI system. Originally defined by a metal bar, now defined based on the speed of light.

The base unit for mass in the SI system. Originally defined by a platinum-iridium cylinder, now defined based on Planck's constant.

The base unit for time in the SI system. Defined based on the vibrations of a Cesium atom.

Units derived from the combination of base SI units, such as area (m²), volume (m³), speed (m/s), etc.

Prefixes like kilo (k), milli (m), and micro (µ) added to base units to represent multiples or fractions of the base unit.

Units used for various physical quantities like length, mass, time, temperature, electric current, luminous intensity, and amount of substance.

To derive a unit for a physical quantity, we need to find the relationship between the quantity and base quantities, then substitute their units. For example, area is length × length, so its unit is m² (meter squared).

Force is defined as mass × acceleration, and acceleration is change in velocity/time, which is length/time². So, the unit of force can be derived as kg × m/s² (kilogram-meter per second squared).

The SI unit for area is m² (square meter), and for volume is m³ (cubic meter).

Derived units can be expressed using combinations of base units. For example, the unit of speed (m/s) is derived from length (m) and time (s).