CLASS 6 · SCIENCE · CHAPTER 5
Simple, student-friendly answers to all 13 end questions, plus the chapter’s measurement and motion prompts and activities.
26 worked answers · short steps first, explanations when you need them
Textbook pages 97–99
Question 1
City distance: km; coin: mm; eraser: cm; school ground: m.
Delhi–Lucknow: kilometre; coin thickness: millimetre; eraser: centimetre; school ground: metre.
Question 2
(i) T (ii) T (iii) F.
Question 3
Handspan.
Handspan. Its size is different for different people.
Question 4
Sample: ruler—1 mm; metre scale—1 mm; tape—1 cm. Use the smallest marks on your own tools.
Sample table: 15-cm ruler — 1 mm; metre scale with mm marks — 1 mm; tailor’s tape marked in cm — 1 cm. Check the actual markings on your tools, as they may differ.
Question 5
1.5 × 1000 = 1500 m.
1.5 km = 1500 m.
Question 6
Use a thread around the base, straighten it, then measure it. Record your object’s result.
Sample method: wrap thread around the base, mark the full curve, straighten the thread, and measure it with a ruler. Record your own result in centimetres.
Question 7
If height is 145 cm: 1.45 m = 145 cm = 1450 mm. Use your own measurement.
Example for a height of 145 cm:
Question 8
Number of coins ≈ notebook side length ÷ coin diameter. Example: 24 cm ÷ 2 cm = 12 coins.
The number depends on your notebook and coin. Example: if the side is 24 cm and the coin is 2 cm wide, estimate 24 ÷ 2 = 12 coins. Verify by placing them in a row without gaps.
Question 9
Linear: car, lift. Circular: fan, wheel. Oscillatory: swing, pendulum.
Linear: a straight-moving car, a lift. Circular: a fan blade, a wheel. Oscillatory: a swing, a pendulum.
Question 10
mm: coin, seed, bead. cm: pencil, book, spoon. m: room, board, tree.
Sample: mm—coin thickness, seed, bead; cm—pencil, book, spoon; m—room length, board length, tree height. These are examples; actual measurements depend on the object.
Question 11
Straight portions: linear motion. Loop portions, if shown: circular motion. Curved non-loop portions: curved motion.
The ball has linear motion on straight track sections and curved motion on curved sections. If a section forms a loop, its motion there is circular. Use the bends shown between A–B, B–C, C–D, D–E, and E–F to label each section; motion can change as the track changes.
Question 12
Avoid cloth and stretchable rubber because they bend or stretch; paper is also flimsy.
She should not use cloth or stretchable rubber because they bend or stretch and can give incorrect measurements. Paper is also less durable and may bend. Plywood or steel is more suitable if marked accurately.
Question 13
Make matching cards for equivalent lengths, e.g. 2 m = 200 cm. Each correct match earns a point.
Sample game: make pairs such as 2 m and 200 cm, 35 cm and 350 mm, and 4 km and 4000 m. Shuffle the cards and take turns matching equivalent lengths. Each correct match scores one point.
Textbook pages 80–96, 99–100
Question p1
Kilometres suit city distances; millimetres suit page thickness.
Use kilometres for long distances and millimetres for very small thicknesses. Choosing a suitable unit makes measurements easier to understand.
Question p2
Nearly the same, if the scale is straight, starts at zero, and is read from above.
They should get nearly the same result if they use the scale correctly: align it with the table, start at zero, and read directly above the mark.
Question p3
Length = end reading − start reading.
Use a clear mark as the start and subtract: length = ending reading − starting reading. For example, 10.4 cm − 1.0 cm = 9.4 cm.
Question p4
Use flexible tape or a thread; straighten and measure the thread.
Measure along it with flexible tape, or use a thread and then measure the straightened thread with a ruler.
Question p5
A fixed point used to describe position; compare from the same reference point.
A reference point is a fixed place used to describe position or distance. People may disagree because they are measuring from different homes. Compare distances from the same reference point.
Question p6
They show distance to Delhi; a smaller number means she is closer.
They show distance from a named place. Padma knew she was closer because the distance on the stones decreased from 70 km to 60 km.
Question p7
It moves when its position changes over time relative to a reference point.
An object is moving if its position changes with time relative to a reference point.
Question p8
At rest relative to the bus; moving relative to outside objects.
They are at rest relative to the bus, but moving relative to objects outside it. Motion depends on the chosen reference point.
Question p9
Examples vary. Compare each object’s position to a fixed point over time.
Sample lists: moving—walking student, flying bird, rolling ball, moving bus, rotating fan; at rest—desk, tree, parked bicycle, closed door, building. These are judged relative to the ground.
Question p10
Lift: linear; merry-go-round: circular; swing: oscillatory.
Examples: lift moving up (linear), merry-go-round (circular), swing moving back and forth (oscillatory).
Question p11
Measure many pages together, then divide thickness by page count.
Measure a stack of pages and divide its thickness by the number of pages. For example, a 5 mm stack of 50 pages gives about 0.1 mm per page.
Question p12
Measure length and widest breadth; record each leaf. Natural leaves vary.
Measure and record the length and widest breadth of each leaf. Leaves from one tree can still differ because they grow under slightly different conditions.
Question p13
Distance = wheel circumference × number of turns.
Distance travelled ≈ wheel circumference × number of turns. If the wheel circumference is 2 m and it turns 100 times, the distance is about 200 m.