CBSE Class 6 Science Motion And Measurement Notes

CBSE Class 6 Science - Motion and Measurement Learning the important concepts is very important for every student to get better marks in examinations. The concepts should be clear which will help in faster learning. The attached concepts made as per NCERT and CBSE pattern will help the student to understand the chapter and score better marks in the examinations. 

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, timesecond, 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.

Q1. Name few means of transport available in ancient times before the invention of wheel.

Ans1. Boats and domestic animals.

Q2. Which invention made a great change in modes of transport

Ans2. invention of the wheel.

Q3. Name some commonly used units of measurements in ancient times.

Ans3. the length of a foot, the width of a finger, and the distance of a step, a handspan  and a cubit.

Q4. In taking measurement of a length using a scale, what precautions should we take?

Ans4. we need to take care of the following:

1. Place the scale in contact with the object along its length as shown in Fig.10.7. NCERT

2. In some scales, the ends may be broken. You may not be able to see the zero mark clearly (Fig.10.8 (a)]. In such cases, you should avoid taking measurements from the zero mark of the scale. You can use any other full mark of the scale, say, 1.0 cm . Then you must subtract the reading of this mark from the reading at the other end.

3. Correct position of the eye is also important for taking measurement. Your eye must be exactly in front of the point where the measurement is to be taken.

Q5. How do you decide whether an object is in motion or at rest?

Ans5. If a body changes its position with respect to its surroundings, it is said to be in motion, and if it does not change its position with respect to its surroundings, it is at rest.

Q6. How can we decide that how fast or slow a motion is.

Ans6. Motion is a change in the position of an object with time.

The change in this position can be determined through distance measurements.

This allows us to know how fast or slow a motion is.

The movement of a snail on the ground, ----SLOW

An aeroplane flying high up in the air - Fast

Q7. Name the S.I. unit of length.

Ans.7 Metre is the unit of length in SI unit.

Q8. The ball is rolling on the ground – Name the type of motion exhibited by it.

Ans.8 the ball undergoes a rectilinear motion as well as rotational motion.

Q9. What do you mean by measurement?

Ans.9 measurement means the comparison of an unknown quantity with a known quantity.

Q10. In how many parts do we express the result of a measurement ?

Ans.10 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 in Activity 1, the length of the room is found to be 12cm. 12 is the number and cm is the unit selected for the measurement.

Q11. When is the motion of a body said to be rectilinear ,circular, periodic ?

Ans.11 When objects move along a straight line,the type of motion they possess is rectilinear motion.

When the distance of the object from the centre remains the same, the type of motion It possesses is circular motion.

When an object or a part of it repeats its motion after a fixed interval of time, the type of motion It possesses is periodic motion.

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