## Revision Notes of Ch 10 Motion and Measurement of Distances Class 6th Science

Topics in the chapter

• Transport
• Transport system evolution
• Distance and length
• Measurement
• Standard unit of measurement
• Needs for standard units of measurement
• Rules for writing symbols of units
• Motion
• Types of motion

Transport

→ It is a mechanism in which a thing is carried from one place to another.

Transport system evolution

→ In the earlier times, land transport was done using animals or human backs, while, water transport was done on hollow wooden logs or simple wooden boats.

→ After the invention of wheel, bullock carts, camel carts were developed.

→ Transport then evolved in the 19th and 20th century to bus, trains, cars, and airplane, jets, steam and motor boats, etc.

Distance

→ It is length of the space between two points or between two places is called distance.

→ Example: If the two points are close by, the distance between them will be small otherwise if the two points are far off, then the distance between them will be large.

Length

→ Length tells us how long an object is.

→ Measurement is comparison on an unknown quantity with a known quantity. The known quantity is called Unit.

→ Measurement consists of two parts, a number (quantity) and a unit.

→ Depending upon the unit, the number changes.

Standard Units of Measurements

→ Scientists all over the world have accepted a set of standard units for measurements. This system of units is called International System of Units (SI units).

Needs for standard units of measurement

→ Units like foot, hand span, cubit, footstep etc., vary.

→ They depend upon the size of an individual, hence such units cause confusion in measurements.

→ Example: length-meter, time-second, mass- kilogram.

Rules for writing symbols of units

→ Units are usually written in small letters

→ It is not given in plural form

→ It is not followed by a full stop unless it is at the end of the sentence.

Measuring Length of a Curved line

→ Instead of straight scale using measuring tape for the measurement of curved line or surface.

Motion

→ Any change in position with time can be termed as motion.

→ A motion can be termed as slow or fast based on the distance it covers in a specific amount of time.

→ The objects which are not moving are said to be at rest.

Classification of motion on the basis of the path they follow

(i) Rectilinear Motion : Motion where objects move along a straight line.

Examples: sprinters in race, falling stones etc.

(ii) Circular Motion : Motion where objects move along a circular path.

Examples: rotation of earth.

(iii) Rotational Motion : A type of circular motion where an object spins on its own axis, it is called rotational motion.

Example: rolling ball, spinning top etc.

(iv) Periodic Motion : Motion where the object repeats its motion after a fixed interval of time. Examples: motion of swing, pendulum etc.

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