Chapter 5, Measurement of Length and Motion discusses how we measure length accurately and how we describe the movement of objects around us. The chapter begins with the story of a girl named Deepa and her friends, who try to measure the length of a table using their handspans and discover that everyone gets a different answer. This simple observation shows that because body based units like handspan, angula and dhanusa vary from person to person, they cannot be used as reliable standards and the world needs a common system that gives the same result regardless of who is measuring.
The chapter first discusses the ancient Indian units of measurement, leading up to the modern International System of Units, which establishes the metre as the standard unit of length. Students then learn how to use a ruler correctly, how to measure curved lengths using a thread and how to convert between millimetres, centimetres, metres and kilometres.
It also introduces the concept of motion, classifying motion into linear, circular and oscillatory types. NCERT Solutions for Class 6 Science for this chapter cover all in text and back exercise questions, helping CBSE Board Class 6 students build confidence for their exams. Chapter 5 involves numbers, units and conversions, making it the foundation for all the quantitative work that students will do in science from this chapter onwards.
Download NCERT Solutions for Class 6 Science Chapter 5 PDF
Download the NCERT Solutions for Class 6 Science Chapter 5 - Measurement of Length and Motion PDF for free and study anytime, anywhere. These solutions are prepared in simple language according to the latest CBSE syllabus and provide accurate answers to all NCERT exercise questions. Use this PDF to complete homework, revise important concepts like units of measurement, length conversion and types of motion, and prepare confidently for your school exams.
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Class 6 Science Chapter 5 Measurement of Length and Motion NCERT Solutions
NCERT Solutions for Class 6 Science Chapter 5 given below cover all the questions in this chapter. These solutions are prepared according to the latest CBSE Board Class 6 syllabus and are designed to help students understand the concepts clearly and write accurate and well-structured answers. By practicing these solutions regularly, students can improve their understanding of the chapter and prepare confidently for school tests and exams.
Q1. Some lengths are given in Column I of Table 5.5. Some units are given in Column II. Match the lengths with the units suitable for measuring those lengths.
| Column I | Column II |
|---|---|
| Distance between Delhi and Lucknow | Kilometre |
| Thickness of a coin | Millimetre |
| Length of an eraser | Centimetre |
| Length of school ground | Metre |
Q2. Read the following statements and mark True (T) or False (F) against each.
(i) The motion of a car moving on a straight road is an example of linear motion.
Answer: True (T)
A car moving on a straight road travels in a straight line, so it shows linear motion.
(ii) Any object which is changing its position with respect to a reference point with time is said to be in motion.
Answer: True (T)
If an object's position changes with time when compared to a reference point, it is said to be in motion.
(iii) 1 km = 100 cm
Answer: False (F)
The correct conversion is:
1 km = 1000 m
and
1 m = 100 cm
Q3. Which of the following is not a standard unit of measuring length?
(i) millimetre
(ii) centimetre
(iii) kilometre
(iv) handspan
Answer: (iv) Handspan
Explanation: A handspan is not a standard unit because it is different for different people. Standard units such as millimetre, centimetre and kilometre are the same everywhere.
Q4. Search for the different scales or measuring tapes at your home and school. Find out the smallest value that can be measured using each of these scales. Record your observations in a tabular form.
Answer:
| Measuring Instrument | Smallest Measurement |
|---|---|
| 15 cm ruler | 1 mm |
| 30 cm ruler | 1 mm |
| Measuring tape | 1 mm |
| Metre scale | 1 mm |
Note: Your observations may be slightly different depending on the measuring tools available.
Q5. Suppose the distance between your school and home is 1.5 km. Express it in metres.
Answer: We know that:
1 km = 1000 m
So,
1.5 km = 1.5 × 1000 = 1500 m
Answer: 1500 metres
Q6. Take a tumbler or a bottle. Measure the length of the curved part of the base of glass or bottle and record it.
Answer: This is an activity-based question. Students should perform the activity using a thread and a ruler.
Sample Observation:
Object: Water bottle
Length of the curved part of the base: 24 cm
Note: The answer may vary depending on the size of the tumbler or bottle used.
Q7. Measure the height of your friend and express it in (i) metres (ii) centimetres and (iii) millimetres.
Answer: This is an activity-based question. Students should measure the height of their friend using a measuring tape or a metre scale.
Sample Answer: Suppose your friend's height is 1.4 m.
In metres: 1.4 m
In centimetres: 140 cm
In millimetres: 1400 mm
Note: Your answer may be different depending on your friend's actual height.
Q8. You are given a coin. Estimate how many coins are required to be placed one after the other lengthwise, without leaving any gap between them, to cover the whole length of the chosen side of a notebook. Verify your estimate by measuring the same side of the notebook and the size of the coin using a 15-cm scale.
Answer:
This is an activity-based question.
Sample Observation:
Length of notebook = 24 cm
Length of one coin = 2 cm
Number of coins required:
24 ÷ 2 = 12
Answer: About 12 coins are needed to cover the length of the notebook.
Note: Your answer may vary depending on the size of the notebook and the coin used.
Q9. Give two examples each for linear, circular and oscillatory motion.
Answer:
Linear Motion
A car moving on a straight road.
A train moving on a straight railway track.
Circular Motion
The blades of a ceiling fan.
A merry-go-round.
Oscillatory Motion
A swing moving to and fro.
A pendulum of a clock.
Q10. Observe different objects around you. It is easier to express the lengths of some objects in mm, some in cm and some in m. Make a list of three objects in each category and enter them in Table 5.6.
| Size | Objects |
|---|---|
| mm | Thickness of a coin, Pencil lead, Thickness of a notebook page |
| cm | Eraser, Spoon, Mobile phone |
| m | Door, Blackboard, Height of a person |
Note: Students may write other suitable examples found around them.
Q11. A rollercoaster track is made in the shape shown in Fig. 5.19. A ball starts from point A and escapes through point F. Identify the types of motion of the ball on the rollercoaster and corresponding portions of the track.
Answer:
| Portion of the Track | Type of Motion |
|---|---|
| A to B | Linear motion |
| B to C | Curved motion |
| C to D to E (Loop) | Circular motion |
| E to F | Linear motion |
Explanation: The ball first moves along a straight path, so it shows linear motion. It then moves through a curved part of the track. While passing through the loop, it moves in a circular path, which is called circular motion. After coming out of the loop, the ball again moves along a straight path until it reaches point F.
Q12. Tasneem wants to make a metre scale by herself. She considers the following materials for it-plywood, paper, cloth, stretchable rubber and steel. Which of these should she not use and why?
Answer: Tasneem should not use paper, cloth or stretchable rubber to make a metre scale.
These materials can tear, fold, bend or stretch easily, so they cannot give accurate measurements.
She should use plywood or steel because they are strong, do not stretch easily and help measure length correctly.
Q13. Think, design and develop a card game on conversion of units of length to play with your friends.
Answer: Sample Card Game: "Length Match"
Materials Required
Small cards
Pen or marker
How to Prepare
Write different lengths on some cards, such as 1 km, 2 m, 50 cm, 1000 mm.
Write their equivalent values on separate cards, such as 1000 m, 200 cm, 0.5 m, 100 cm.
How to Play
- Shuffle all the cards.
- Place them face down.
- Players take turns picking two cards.
- If the two cards show the same length in different units, the player keeps the pair.
- The player with the most correct pairs wins the game.
This activity makes learning unit conversions fun and helps students remember them easily.
Chapter Overview
Chapter 5 begins by explaining why standard units of measurement are necessary. Through the story of Deepa and her friends, students learn that measuring objects using handspans gives different results because everyone's handspan is different. The chapter also introduces ancient Indian units of measurement such as angula, dhanusa and yojana before explaining the International System of Units (SI units). It was developed to provide a common and universally accepted system of measurement. It also explains that every measurement consists of two parts: a number and a unit.
The chapter discusses the SI units of length and explains the relationship between kilometre, metre, centimetre and millimetre. Students learn the conversion rules: 1 km = 1000 m, 1 m = 100 cm and 1 cm = 10 mm. The chapter also explains the correct method of measuring length using a scale, including how to measure accurately when the zero mark is damaged or missing. It introduces the thread method for measuring curved lines by placing a thread along the curve and then measuring its length with a ruler.
The chapter explains that the position of an object is described with respect to a reference point. An object is said to be in motion if its position changes with time relative to a reference point, while it is said to be at rest if its position does not change. Students also learn that rest and motion depend on the reference point chosen. For example, passengers sitting inside a moving bus are at rest with respect to each other but are in motion with respect to the road.
The chapter explains three types of motion. Linear motion takes place along a straight line, circular motion takes place along a circular path and oscillatory motion is a to-and-fro motion about a fixed point. It also explains periodic motion, which is any motion that repeats itself after equal intervals of time. Through simple activities, the chapter helps students understand how measurement and motion form the foundation of physics.
Topics Covered in This Chapter
- Why standard units of measurement are necessary.
- Traditional Indian units of length and their historical significance.
- Evidence of measurement in the Harappan Civilization.
- The International System of Units and the SI unit of length.
- Millimetre, centimetre, metre, kilometre and their conversion.
- Correct technique for using a ruler.
- Measuring curved lengths using a thread or flexible measuring tape.
- The concept of a reference point and how it is used to describe position.
- The Concept of Motion.
- Types of Motion with examples.
How to Prepare for This Chapter Using NCERT Solutions?
For Chapter 5, start by reading the NCERT textbook and make sure you understand why standard units are needed. Understanding the reasoning makes the rest of the measurement concepts much easier. If you are unsure about any exercise, refer to the NCERT Solutions after attempting it yourself. Next, learn the unit conversions thoroughly. Remember that 1 km = 1000 m, 1 m = 100 cm and 1 cm = 10 mm. Then practice converting units.
Convert km to metres, then to centimetres and millimetres. Convert mm to centimetres, then to metres and kilometres. The exercise questions in this chapter include matching lengths to appropriate units and expressing a measurement in multiple units. For measurement questions, remember two things clearly. First, when the zero mark of a ruler is broken, start from any clear marking, note that value and subtract it from the final reading. Second, curved lengths are measured using a thread, not a rigid ruler.
For motion, learn the three types of motion with at least two examples of each. Once the examples are clear, apply them to the roller coaster question. A straight portion of the track gives linear motion. A loop gives circular motion. A back and forth dip gives oscillatory motion. The roller coaster question is important for school exams. For the concept of reference points and relative motion, always remember that an object's motion or rest is not absolute but depends on the chosen reference point. This concept often appears as a reasoning type question.
After completing the chapter, practice all the textbook questions yourself before checking the solutions. For Class 6 Measurement of Length and Motion MCQs, the most frequently asked questions are the SI unit of length, the conversion relationships between units, the rules for writing units correctly, the definition of motion relative to a reference point, the three types of motion with examples and the method of measuring curved lengths.
