NCERT Question-Answer Solution for Class 6 Science Chapter 5 – Measurement of Length and Motion
Complete NCERT Question–Answer Set for Class 6 Science (Curiosity Textbook) – Chapter 5: Measurement of Length and Motion
Class 6 Science NCERT Solution – Chapter 5 Measurement of Length and Motion
Measurement of Length and Motion – Full NCERT Question–Answer Set (CBSE Class 6 Science – Curiosity Book)
CLASS 6 SCIENCE – CHAPTER 5
MEASUREMENT OF LENGTH AND MOTION
FULL QUESTION–ANSWER SET NCERT Solution
SECTION A: NCERT End-Exercise Questions (with Answers) – Let us enhance our learning
Match the Columns
| Column I | Column II |
|---|---|
| Distance between Delhi and Lucknow | centimetre |
| Thickness of a coin | kilometre |
| Length of an eraser | metre |
| Length of school ground | millimetre |
Answers:
| Column I | Column II | Answer |
|---|---|---|
| Distance between Delhi and Lucknow | kilometre | kilometre |
| Thickness of a coin | millimetre | millimetre |
| Length of an eraser | centimetre | centimetre |
| Length of school ground | metre | metre |
2. True or False
(i) The motion of a car moving on a straight road is an example of linear motion.
Answer: True
(ii) Any object which is changing its position with respect to a reference point with time is said to be in motion.
Answer: True
(iii) 1 km = 100 cm
Answer: False (1 km = 1000 m = 1,00,000 cm)
3. Which of the following is not a standard unit of measuring length?
(i) millimetre
(ii) centimetre
(iii) kilometre
(iv) handspan
Answer: handspan
4. Smallest value measurable in scales
(Students find smallest division on their ruler.)
Example answer:
Steel ruler – 1 millimetre
Measuring tape – 1 millimetre
Plastic ruler – 1 millimetre
5. Convert 1.5 km into metres
1 km = 1000 m
1.5 km = 1500 m
Answer: 1500 metres
6. Measure curved part of a bottle
Answer:
Use a thread to cover the curved part, straighten it, then measure using a scale.
7. Express height of friend in metres, centimetres, millimetres
Example answer:
Height = 1.42 m = 142 cm = 1420 mm
8. Estimate how many coins cover notebook length
Answer:
(Method)
Find coin diameter, measure notebook length, divide length by coin diameter.
9. Give two examples of each motion
Linear motion:
- Dropping an eraser
- Moving car on straight road
Circular motion:
- Merry-go-round
- Stone tied to a string being whirled
Oscillatory motion:
- Swing
- Pendulum
10. Objects measured in mm, cm, m
Answer (Example):
mm:
Thickness of coin
Needle
Staple pin
cm:
Pencil
Notebook
Mobile phone
m:
Room length
Height of door
Length of corridor
11. Rollercoaster track (Fig 5.19)
Track portions:
A → B: Linear motion
B → C: Circular/curved motion
C → D → E: Linear + curved combinations
E → F: Linear motion
12. Which materials should Tasneem avoid for making a metre scale? Why?
Avoid:
Paper (tears easily),
Cloth (not rigid),
Stretchable rubber (changes length).
Use:
Steel or plywood (rigid and non-stretchable).
13. Design a card game on conversion of units
Answer:
Make cards with different unit conversions like:
1 m = 100 cm
1 km = 1000 m
1 cm = 10 mm
Players draw cards and answer quickly to earn points.
SECTION B: In-Text NCERT Questions (with Answers) – Measurement of Length and Motion
1. What did Deepa’s mother mean by “char angula”?
Answer:
Char angula means four finger-widths. It is a traditional unit of measurement used in earlier times.
2. Are the tape and rod similar to the scale in the geometry box?
Answer:
Yes. All are measuring tools used to measure length, though they differ in size and flexibility.
3. Why did the handspan measurements of the table differ for each child?
Answer:
Because handspans are not the same size for all people. Non-standard units vary from person to person.
4. Why is there a need for standard units of measurement?
Answer:
Because non-standard units give different results for the same object. Standard units give uniform and accurate measurements for everyone.
5. What is the SI unit of length?
Answer:
The SI unit of length is metre (m).
6. Why should the eye be positioned exactly above the marking while measuring?
Answer:
To avoid parallax error, which occurs when the scale is viewed from an angle, causing incorrect readings.
7. How can you use a broken scale to measure length?
Answer:
Start measuring from any clear full mark (like 1.0 cm), measure till the end point, and subtract the starting reading from the final reading.
Example:
Final reading = 10.4 cm
Starting reading = 1.0 cm
Length = 10.4 – 1.0 = 9.4 cm
8. Why are some measuring devices flexible?
Answer:
Flexible devices like measuring tapes are used to measure curved or round surfaces where rigid scales cannot be used.
9. Why do children get different results even when using the same scale?
Answer:
Because of wrong eye position, improper placement, or reading from the wrong mark.
10. What is a reference point?
Answer:
A reference point is a fixed point from which distance or position is measured.
11. When is an object said to be in motion?
Answer:
An object is in motion when its position changes with respect to a reference point over time.
12. When is an object at rest?
Answer:
When its position does not change with respect to a reference point with time.
13. Why do passengers inside a bus feel at rest while the bus is moving?
Answer:
Because passengers are viewed relative to the bus. Their position does not change with respect to the bus (the reference point).
14. What is linear motion?
Answer:
Motion in a straight line is called linear motion.
15. What is circular motion?
Answer:
When an object moves along a circular path, it is circular motion.
16. What is oscillatory motion?
Answer:
Motion in which an object moves to and fro about a fixed point is oscillatory motion.
17. What is periodic motion?
Answer:
When an object repeats its motion after equal intervals of time.
SECTION C: Learning Further – Suggested Answers – Measurement of Length and Motion
1. How to find thickness of a single page
Measure thickness of 100 pages, divide by 100.
Example:
Thickness of 100 pages = 1 cm
Thickness of 1 page = 1/100 cm = 0.01 cm
2. Why do leaves of the same tree vary in length and breadth?
Answer:
Because of age differences, sunlight variation, nutrients, and environmental factors.
3. Units used in olden days
Answer:
People used angula, hasta, dhanusa, yojana, handspan, foot, arm length.
Excavated scales from Harappa also show measurement markings.
4. Maze activity
(Student-based; no fixed answer.)
5. Height-tracking activity
Record height every three months.
6. Bicycle wheel distance measurement
Count the number of wheel rotations → multiply by circumference of wheel.
Method:
Distance = Number of turns × Circumference
SECTION D: Additional Questions (with Answers) – Measurement of Length and Motion
1. Why is zero mark of scale important?
Answer:
Because measurement begins from zero. If zero is broken, use another full marking and subtract.
2. Why can’t we use metre scale to measure round objects?
Answer:
Because metre scales are rigid and cannot bend around curved surfaces.
3. What is the smallest measurement on a 15-cm scale?
Answer:
1 millimetre.
4. Why is distance incomplete without a reference point?
Answer:
Because distance must be described from somewhere, otherwise it has no meaning.
5. Why is circular motion called periodic?
Answer:
Because the object returns to the same position after equal time intervals.
SECTION E: HOTS (Higher Order Thinking Questions) – Measurement of Length and Motion
1. Two students measure the same book but get different results. Why?
Answer:
Due to wrong eye position, scale not aligned properly, or starting at a broken mark.
2. Why do passengers inside a train appear at rest but outside trees appear to move?
Answer:
Because inside the train, passengers are compared to the train (reference point).
Outside objects move relative to the train.
3. Can an object be at rest and in motion at the same time?
Answer:
Yes.
Example: A passenger in a moving bus is at rest relative to the bus but in motion relative to trees and buildings.