Class 5 Notes - Measurement of Length

Introduction

Length is a fundamental physical quantity that helps us determine how long or short an object is. Measurement of length is crucial in everyday life, engineering, architecture, and science.

Units of Length

1. Non-Standard Units

  • Handspan: Distance from the thumb to the little finger.
  • Cubit: Length from the elbow to the middle finger.
  • Footstep: Length of a step taken by a person.

2. Standard Units

  • Millimeter (mm)
  • Centimeter (cm)
  • Meter (m)
  • Kilometer (km)

Conversion of Units

Understanding conversions between units is essential:

  • 1 km = 1000 m
  • 1 m = 100 cm
  • 1 cm = 10 mm

Example: Convert 5 km to meters:

5 km = 5 × 1000 = 5000 meters.

Measuring Instruments

  • Ruler
  • Measuring Tape
  • Meter Rod
  • Odometer
  • Vernier Caliper

Methods of Measuring Length

1. Direct Measurement

Using rulers, measuring tapes, etc.

2. Indirect Measurement

Used for large distances like roads or rivers.

Word Problems

Problem: A rope is 6 meters long. If it is cut into 3 equal parts, what is the length of each part?

Solution: 6 m ÷ 3 = 2 m each.

Summary

Length measurement is an essential concept that involves units, conversions, and different tools for accuracy.