NEETClass 11thClass 12thClass 12th PlusJEEClass 11thClass 12thClass 12th PlusClass 6-10Class 6thClass 7thClass 8thClass 9thClass 10thOnline CoursesDistance LearningInternational OlympiadNEETClass 11thClass 12thClass 12th PlusJEE (Main+Advanced)Class 11thClass 12thClass 12th PlusJEE MainClass 11thClass 12thClass 12th PlusClass 6-10Class 6thClass 7thClass 8thClass 9thClass 10thKCET/MHT-CETKCETMHT-CETNEET20262025202420232022JEE20262025202420232022Class 6-1020262025JEE MainPrevious Year PapersSample PapersMock TestResultAnalysisSyllabusExam DatePercentile PredictorAnswer KeyCounsellingEligibilityExam PatternJEE MathsJEE ChemistryJEE PhysicsJEE AdvancedPrevious Year PapersSample PapersMock TestResultAnalysisSyllabusExam DateAnswer KeyEligibilityExam PatternRank PredictorNEETPrevious Year PapersSample PapersMock TestResultAnalysisSyllabusExam DateCollege PredictorAnswer KeyRank PredictorCounsellingEligibilityExam PatternBiologyNCERT SolutionsClass 6Class 7Class 8Class 9Class 10Class 11Class 12TextbooksCBSEClass 12Class 11Class 10Class 9Class 8Class 7Class 6SubjectsSyllabusNotesSample PapersQuestion PapersICSEClass 10Class 9Class 8Class 7Class 6State BoardBiharKarnatakaMadhya PradeshMaharashtraTamilnaduWest BengalUttar PradeshOlympiadMathsScienceEnglishSocial ScienceNSOIMONMTCTALLENTEXASATInstant Online ScholarshipAIOT(NEET)ALLEN for SchoolsAbout ALLENBlogsNewsCareersRequest a call backBook a demo
CBSE Notes Class 6 Science Chapter 5 Measurement of Length and Motion
Measurement is an important part of our daily life. We measure things like length, height, and distance to understand their size. This chapter introduces students to the concept of measurement and explains how to measure length using standard units.
Students learn about different measuring tools, such as rulers and measuring tapes, and understand why standard units are important for accurate measurement. This chapter also explains how measurement and motion are used in everyday life.The chapter PDF summarises the main concepts in a simple format for quick revision. Students can also explore Class 6 Science Notes to revise other chapters and strengthen their understanding of key science concepts.
1.0Measurement of Length and Motion Class 6 Science Chapter 5 - Revision Notes
Measurement compares an unknown physical quantity against a fixed standard unit to determine size, distance, or length accurately. Motion occurs when an object changes its position over time relative to a fixed reference point, taking forms such as translational, circular, rotational, periodic, and oscillatory motion.
Key Concepts:
- Measurement: The process of comparing an unknown physical quantity with a known fixed standard quantity of the same kind.
- Types of Motion: Include rectilinear, curvilinear, circular, rotational, periodic, and oscillatory motion.
- Parts of Measurement: A complete measurement consists of a numerical magnitude and a standard unit.
- Non-Standard Units: Ancient units based on human body parts, such as handspans, cubits, fathoms, and paces, varied between individuals and lacked uniformity.
- SI System: The International System of Units provides globally accepted standards for consistent scientific communication, with the metre (m) as the standard unit of length.
- Motion and Rest: An object is in motion if its position changes over time relative to a stationary reference point. It is at rest if its position remains unchanged.
Need for Standard Units and the SI System
Earlier, people measured length using body parts such as handspans, cubits and foot lengths. Since these measurements varied from person to person, they were not reliable. The metric system was introduced in France in 1790 to standardise measurements. Scientists later adopted the International System of Units (SI) for uniform measurements worldwide, with the metre as the SI unit of length.
Unit Conversions and Measuring Tools
Length measures the distance between two points. Millimetres and centimetres are used for small lengths, metres for everyday distances and kilometres for longer distances. Important conversions include 1 m = 100 cm, 1 m = 1,000 mm, 1 km = 1,000 m, 1 cm = 10 mm and 1 inch = 2.54 cm. Tailors use flexible measuring tapes, while rulers and metre scales are suitable for straight lengths.
Describing Position and Relative Motion
To describe an object's position, we use a fixed reference point called the origin, a direction, and the distance from the origin. Motion and rest depend on the reference point. For example, a passenger sitting in a moving car is at rest relative to another passenger but in motion relative to trees along the roadside.
Classification of Types of Motion
- Translational Motion: When an object moves from one place to another without changing its orientation. Rectilinear motion follows a straight path, like a train on straight tracks, while curvilinear motion follows a curved path, like a ball thrown in the air.
- Circular Motion: An object moving along a circular path around a fixed point, such as an athlete running on a circular track.
- Oscillatory Motion: Repeated to-and-fro movement around a mean position, such as a swinging girl or a rocking horse. All oscillatory motions are periodic, but not all periodic motions are oscillatory because some, like Earth's rotation, do not involve to-and-fro movement.
- Rotational Motion: An object spins around an axis passing through its body, such as a spinning top, windmill blades or Earth rotating on its axis.
- Periodic Motion: Motion that repeats at equal time intervals, such as Earth's revolution around the Sun or a clock pendulum's motion.
- Rolling Motion: A combination of translational and rotational motion. For example, a bicycle wheel rotates around its axle while moving forward along the road.
2.0Terminologies to know - Measurement of Length and Motion
- Measurement: The comparison of an unknown physical quantity with a known standard quantity of the same kind.
- Standard Unit: A fixed, internationally accepted quantity used as a reference to express physical measurements.
- Reference Point: A fixed starting location, also called the origin, used to specify the position of an object.
- Parallax Error: An apparent shift in scale reading caused by viewing the scale alignment from an oblique angle rather than vertically above the mark.
- Rectilinear Motion: Movement of an object in a straight line.
- Rotational Motion: The spinning of an object around an internal fixed axis.
- Oscillatory Motion: The back-and-forth movement of an object about its central position.
3.0Learning Guide for Class 6 Science Measurement of Length and Motion- Chapter 5
Textbook Experiments and Activities:
- Activity on Non-Standard Units:
Students measure the length of a table using their handspan and compare results with classmates. Purpose and Observation: Handspan measurements differ among students because hand sizes vary, proving that body parts lack uniformity and cannot serve as standard units.
- Activity on Measuring Single Sheet Thickness:
Count 100 consecutive sheets of a textbook, press the stack firmly, measure total thickness using a metric scale, and divide total thickness by 100. Purpose and Observation: Single sheet thickness is too thin for direct ruler measurement, so averaging across a large stack provides an accurate value.
- Activity on Measuring a Curved Line:
Place a flexible thread tightly along a curved line, mark the endpoints with a pen, straighten the thread, and measure the distance between marks against a scale. Purpose and Observation: Rigid scales cannot bend along curves, but a flexible thread transfers curved lengths into straight measurements.
- Activity on Bicycle Distance Counter:
Wrap a string around a bicycle wheel edge to find its circumference, attach a flexible strip to a spoke that clicks against the frame per rotation, count total clicks during a ride, and multiply circumference by rotation count. Purpose and Observation: Total distance equals wheel circumference multiplied by number of revolutions, demonstrating mechanical distance measurement.
Everyday Examples:
- Measuring height or waist girth using a flexible tape rather than a rigid metre scale.
- Observing a ceiling fan or windmill blades demonstrating rotational motion around an axis.
- Watching a child on a playground swing illustrating oscillatory and periodic motion.
Revision Tips:
- Remember that 1 m = 100 cm = 1000 mm, and 1 km = 1000 m.
- Remember that all oscillatory motions are periodic, but periodic motions like Earth's rotation are not oscillatory because they do not reverse direction.
Safety Rules and Measurement Care:
- Place the measuring scale in contact with the object along its entire length.
- If the zero mark of a scale is broken or worn out, align the object with another clear mark like 1.0 cm and subtract that starting value from the final reading.
- Position the eye directly vertically above the mark being read to avoid parallax error.
4.0Explore Chapter-wise Class 6 Science Notes
5.0Additional Study Materials for Class 6 Science
6.0Find the Right Study Resources for Class 6
7.0Key Features of CBSE Class 6 Science Notes Chapter 5 : Measurement of Length and Motion
- Logical Process Breakdowns: Detailed, step-by-step guides on how to measure curved lines using a thread and how to avoid Parallax Error by positioning the eye correctly.
- Enhanced Visual Learning: Features clear diagrams distinguishing between different types of movement and the evolution of transport, making history and physics visually connected.
- Real-World Connectivity: Bridges the classroom to the world—from calculating the distance to school to understanding the rotation of a ceiling fan or the swing of a pendulum.
- Global Standard Units: A look at the SI System and how it ensures that a "meter" is the same length in India as it is in any other country.
- The Toolbox of Measurement: Mastering the use of rulers, measuring tapes, and meter scales for different surfaces.