# CBSE Class 6 Science Notes Chapter 10 Motion and Measurement of Distances

CBSE Class 6 Science Notes Chapter 10 Motion and Measurement of Distances are given below. Our notes are designed by the subject experts and are as per the NCERT guidelines. These notes include all the important points of the chapter in detailed way, so you can refer to this whenever required. Study Path provides CBSE Class 6 Science Notes Chapter 10 that are easy to understand and also free downloadable PDF format, so students can practice it for their studies and get good marks in their examinations.

## Motion and Measurement of Distances Class 6 Notes Science Chapter 10

Introduction

With the changing times, transport also has gone through various modifications i.e. from animals to the invention of wheels. The evolution of transport is evident when we observe the fast cars, bullet trains etc. Even today new modes of transport are being researched upon.

Distance: How far an object travels constitutes distance!! The GPS system introduced these days accurately measures the distance from one place to another.

Arbitrary ways to measure the length or width:

Measuring using handspan and measurement by a string were used in ancient times but these methods are not so reliable and hence some standard units of measurement have been introduced.

Standard Units of Measurement

Earlier the ‘cubit’ was accepted as a standard unit in Egypt. A cubit meant the length between fingertips and elbow. Owing to the differences in the length of body parts of each person these arbitrary systems became obsolete. Other units used earlier were ‘foot’, end of outstretched arm and chin, fist, etc.

Nowadays, the International System of units or the SI units have been accepted all over the world as a standard unit of measurement.

1 m = 100 cm
1 kg = 1000 g
1s = 1/60 min

The MKS system i.e. the metre-kilogram-second system is called the SI System.

Standardising length measurement

• Scientists from all over the world have accepted a common standard units of measurement.
• The International System of Units (S.I unit) was set up as the convention for measurement worldwide.
• A metre is the SI unit of length. It has 100 equal divisions called as centimetres.
• To measure large distances we use kilometres. 1 Km = 1000 metres.

Zero error and Correct way to measure length

• Scale must be in contact with the object being measured.
• If scales are broken or the zero mark is not visible, it can lead to a zero error. Then measuring from a different mark must be carried out.
• The correct reading will be obtained by subtracting the value from the full mark considered as the zero.
• While measuring the eye must be exactly above the point where the measurement is to be taken, in order to avoid parallax errors.

Parallax

Parallax is the displacement or the change in the apparent position of the object when viewed from two different points of views. This type of error while measuring is called as parallax error.

Correct Way to Use a Mater Scale

Step 1: Keep the scale in contact with the object to be measured.

Step 2: Start measuring from the 0 mark of the scale.

Step 3: To avoid taking incorrect measurements the eye position should be correct. Consider the following figure:

The eye position in the centre is correct to get an accurate measurement, while the ones in the left and right direction will give some error in measurement.

Measurement Along Curved Line

Is it possible to measure a curved line with a metre scale? Well, it is not so. Hence to measure a curved line the following steps can be taken into account:

• Take a thread and tie a knot at one end.
• From this end measure a small portion of the curved line which is somewhat straight and put the thumb.
• Now again start from the thumb marked position and measure another small portion of the line.
• Repeat this process until you reach the end of the line. Tie a knot on the thread on reaching the end. Now measure the two knots using a metre scale.

Motion

• A body is in a state of rest when it does not change its position with respect to time.
• A body is said to be in motion when it changes its position with respect to time.

Means of transport

• Ever since ancient times, humans have devised different means of transport to traverse from one place to another.
• They designed boats that resemble the shapes of animals living in water to travel across water bodies. They invented the wheel, which led to inventions like carts and other animal driven modes of transport.
• During the beginning of the 19th-century humans designed the steam engine, which was followed by automobiles and motorised vehicles.

Measuring Length: A History

Length and distance

• Distance is the measure of how far or long something is. E.g.: the length of a table, or a soccer field or, how far is Mumbai from Delhi?
• Length can be measured in terms of a unit. A unit is a comparison of an unknown quantity with that of a known quantity. It is required to establish a common standard or convention in order to make calculations and analysis easier worldwide.

Traditional methods of measuring length were the use of the length one’s foot or other body parts. But, was inconsistent since this varies from person to person and lacks uniformity.

Motion and Its Types

Rectilinear Motion: When an object moves along a straight line, it is said to be undergoing rectilinear motion. For Example, A train moving along a railway track.

Circular Motion: Have you seen the hands of a clock? The motion exhibited by the hands of a clock is called Circular Motion.

Periodic Motion: When an object repeats its motion after a fixed interval of time it is said to be undergoing periodic motion. For Example, Pendulum

Rotational Motion: This motion can be easily understood by imagining Earth’s rotation. When the Earth spins on its own axis it is said to be undergoing rotational motion.

Time

Time is the unit that measures how long it takes to do anything. Distance is measured with respect to time.

If an object is moving with some speed ‘s’ for a time interval ‘t’, then the distance covered in that time will be = s × t

### Revision Notes for CBSE Class 6 Science Chapter 10 – Free PDF Download

Our Class 6 Revision Notes will provide a quick glimpse of the chapter and improve the learning experience. We have made these revision notes keeping the convenience of students in mind so that it proves more effective. You can easily read these Class 6 notes just by clicking on the chapter names provided above.