Class VI - Science 1

PERIODIC TEST STUDY MATERIAL: MEASUREMENT OF LENGTH AND MOTION

Fill in the Blank Bits

1. The length of a measurement is expressed in two parts: a number and a unit.
2. Units like handspans and other similar body parts differ from person to person.
3. The ancient Indian unit angula is still used by traditional craftspeople like carpenters and tailors.
4. The system of units now used globally is known as the International System of Units or SI units.
5. The SI unit of length is metre.
6. The symbol for the SI unit of length is m.
7. One metre (m) is divided into 100 equal divisions.
8. Each division of a metre is called a centimetre (cm).
9. The length of a millimetre (mm) is equal to one-tenth of a centimeter.
10. For measuring larger lengths, we use a larger unit called a kilometre (km).
11. The relationship between inches and centimetres is 1 inch = 2.54 cm.
12. For measuring the girth of a tree, a flexible measuring tape is more suitable than a metre scale.
13. When distance is stated with respect to a fixed object or point, that point is called a reference point.
14. An object is said to be at rest if its position is not changing with respect to the reference point with time.
15. Both circular and oscillatory motion are periodic in nature because they repeat their path after a fixed interval of time.

Multiple Choice Questions (MCQs)

1. The SI unit of length is:
   (a) Centimetre
   (b) Metre
   (c) Kilometre
   (d) Handspan
2. 1 metre is equal to how many centimetres?
   (a) 10
   (b) 100
   (c) 1000
   (d) 10000
3. Which of the following is NOT a standard unit of measuring length?
   (a) Millimetre
   (b) Kilometre
   (c) Centimetre
   (d) Handspan
4. The smallest value of length measureable using a typical 15-cm scale is:
   (a) 1 cm
   (b) 1 mm
   (c) 0.1 m
   (d) 1 km
5. 1 kilometre is equal to how many metres?
   (a) 100 m
   (b) 10 m
   (c) 1000 m
   (d) 10000 m
6. When measuring length, the scale should be placed:
   (a) Below the object
   (b) In contact with the object along its length
   (c) Perpendicular to the object
   (d) Slightly above the object
7. The correct position of the eye while reading a scale should be:
   (a) To the left of the reading
   (b) To the right of the reading
   (c) Directly above the tip being read
   (d) Parallel to the scale
8. If an object's position changes with respect to the reference point over time, it is considered to be in:
   (a) Rest
   (b) Motion
   (c) Equilibrium
   (d) A fixed state
9. What kind of motion does a heavy box pushed along the floor exhibit?
   (a) Linear motion
   (b) Circular motion
   (c) Oscillatory motion
   (d) Periodic motion
10. The motion of a merry-go-round is an example of:
    (a) Linear motion
    (b) Circular motion
    (c) Oscillatory motion
    (d) To and fro motion
11. What is the definition of oscillatory motion?
    (a) Movement in a straight line
    (b) Movement along a circular path
    (c) Movement to and fro about a fixed position
    (d) Movement that does not change position
12. The length of a leaf is best measured using a:
    (a) Metre scale
    (b) 15-cm scale
    (c) Measuring rod
    (d) Kilometre
13. What units of measurement were found in excavations from sites of the Harappan Civilisation?
    (a) Inches and feet
    (b) Metres and centimetres
    (c) Objects with ruled markings which could be scales
    (d) Only *angula* and *yojana*
14. To measure the length of a curved line using a thread, the thread must first be used to trace the path and then:
    (a) Measured using handspan
    (b) Divided into equal parts
    (c) Straightened and measured using a metre scale
    (d) Weighed to find the length
15. If a scale is broken and the measurement starts at 1.0 cm and ends at 10.4 cm, the length of the object is:
    (a) 11.4 cm
    (b) 1.0 cm
    (c) 9.4 cm (10.4 cm – 1.0 cm)
    (d) 10.4 cm
16. What unit of length is generally used for measuring the distance between Delhi and Lucknow?
    (a) Centimetre
    (b) Metre
    (c) Kilometre
    (d) Millimetre
17. Which of these conditions indicates that an object is in periodic motion?
    (a) It moves along a straight line.
    (b) It changes position constantly.
    (c) It repeats its path after a fixed interval of time.
    (d) It is relative to a reference point.
18. Visually challenged students measure lengths using scales that have:
    (a) Large printed numbers
    (b) Raised markings that can be felt by touching them
    (c) Digital displays
    (d) Flexible measuring tape
19. When writing the symbol for kilometre (km), what rule must be followed?
    (a) It should always be capitalized.
    (b) A full stop must follow it.
    (c) It must be written in lowercase letters and never followed by ‘s’.
    (d) There should be no space between the number and the unit.
20. When Padma was travelling to Delhi, the kilometre stones reading 'Delhi 70 km' and 'Delhi 60 km' indicated that:
    (a) Delhi was moving closer.
    (b) Her position relative to the reference point (Delhi) was changing.
    (c) Her speed was increasing.
    (d) The reference point was moving.

Competency Based Questions

1. A carpenter is building a small wooden shelf. Should he rely on his handspan to measure the required lengths, or should he use a metre scale? Justify your choice.

   He should use a **metre scale** because handspans and similar units differ from person to person, leading to varying or unreliable results. A metre scale provides a standard unit of measurement so that measurements of the same length made by different people do not differ.

2. Hardeep measures the length of the classroom whiteboard using a metre scale and gets a result of "3 metres." Why is it crucial that he also leaves a space between the number and the unit when writing the final measurement?

   It is crucial to leave a space between the number and the unit (e.g., 3 m) because this is a standard rule for writing length measurements.

3. Tasneem wants to make a measurement scale for herself using different materials. Which material, plywood or stretchable rubber, should she definitely *avoid* using, and why?

   She should avoid **stretchable rubber**. A standard scale must maintain a fixed, unchanging length for accurate measurement; stretchable material would lead to measurements that change depending on how hard the material is pulled, making it non-standard.

4. Deepa is riding a bicycle at a constant speed along a straight road. A stationary street lamp is chosen as the reference point. How would the street lamp determine if Deepa is in motion?

   Deepa is in motion because **her position changes with respect to the reference point** (the street lamp) over time.

5. Classify the motion of a ball dropped straight down from a height and the motion of a pendulum in a clock into the specific types of motion described in the chapter.

   The dropped ball exhibits **linear motion** (moving along a straight line), and the pendulum exhibits **oscillatory motion** (moving to and fro about a fixed position).

Important Questions with Answers

1. Define the International System of Units (SI units) and identify the SI unit of length along with its relationship to centimetre and millimetre.

   The **International System of Units** or SI units is the system of standard units of measurement adopted by different countries to eliminate the confusion caused by varied local units.
   The SI unit of length is the **metre (m)**.
   The relationships are: **1 m = 100 cm**, **1 cm = 10 mm**, and **1 km = 1000 m**.

2. Explain why historical units of measurement like handspan or the length of an arm led to confusion and why standard units were necessary.

   Historical units based on body parts, such as handspan (*balisht*) or the length of the arm, caused confusion because they **differ from person to person**. Due to these differences, measurements of the same length made by different people would vary. Standard units were necessary because they do not differ based on the person making the measurement, ensuring reliable and consistent results globally.

3. What is a Reference Point? Use an example to explain how the perception of 'rest' or 'motion' depends on the choice of the reference point.

   A **Reference Point** is a fixed object or point with respect to which distance or position is stated.
   The perception of motion depends on this point. If Deepa considered the **bus or herself** as the reference point, other seated passengers were **at rest** because their position relative to Deepa was not changing. However, if she considered an **object outside the bus** (like a building) as the reference point, the passengers were **in motion** because their positions were continuously changing with respect to the building.

4. Describe the correct procedure for measuring the length of an object when the scale has a broken end or the zero marking is unclear.

   If the ends of the scale are broken or the zero marking is not clear, it can still be used:
   1. Use any **other full mark** of the scale, such as 1.0 cm, as the starting point.
   2. Note the reading at this starting mark and the reading at the other end of the object.
   3. To find the true length, **subtract the reading of the starting mark from the reading at the other end** (e.g., 10.4 cm – 1.0 cm = 9.4 cm).

5. Define Linear, Circular, and Oscillatory motion and provide one example for each type of motion.

   
   1. **Linear Motion:** Motion is linear when an object moves along a **straight line**.
   *Example:* The march-past of students during a parade.
   2. **Circular Motion:** Motion is circular when an object moves along a **circular path**.
   *Example:* Motion of a merry-go-round.
   3. **Oscillatory Motion:** Motion is oscillatory when an object moves **to and fro about some fixed position**.
   *Example:* The motion of a swing.

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