Physical Quantities & Measurement Techniques

Learn it by playing

Answer these questions to earn energy, then fish and explore. No account needed.

For teachers: ready-to-use lesson slides, revision notes, diagrams for Physical Quantities & Measurement Techniques (Physics, CIE) — use them in your lesson, or run the topic as a live class game.

Notes

Measuring Length

Use a **ruler** for small distances (cm), accurate to nearest **millimetre (mm)**.
Use a **tape measure** for lengths of tens of centimetres.
Use a **trundle wheel** for lengths of tens of metres.
For small objects, measure multiple (e.g., 4 ball-bearings) and divide by the number to find one diameter.

Measuring Volume

**Measuring cylinders** measure liquid volume; read from **bottom of meniscus** at eye level.
Volume of an irregular solid is found by **displacement**: record initial and final water levels, subtract.
For small objects, use a smaller cylinder for greater accuracy.

Measuring Time

Use **stop-clocks** or **stopwatches** for time intervals.
**Human reaction time** (~0.25 s) affects short measurements.
Take **multiple readings** (e.g., time for 10 pendulum swings) and divide to reduce uncertainty.
Use a **fiducial marker** (e.g., a dot at equilibrium) to improve timing accuracy.

Scalars & Vectors (Extended)

**Scalars** have only magnitude (e.g., mass, distance, speed, energy).
**Vectors** have both magnitude and direction (e.g., weight, displacement, velocity, force).
**Distance** is total path length (scalar); **displacement** is straight line from start to finish (vector).
**Speed** is distance per time (scalar); **velocity** is displacement per time (vector).

Calculating with Vectors (Extended)

Vectors are drawn as **arrows**: length = magnitude, direction = arrow direction.
To combine two perpendicular vectors, draw a **vector diagram** (scale drawing) or use **Pythagoras** and **trigonometry**.
**Resultant vector** = diagonal of rectangle formed by components.
Use **soh-cah-toa** to find angles; Pythagoras for magnitude.

Particle arrangement in solids, liquids, and gases (not directly needed but illustrates measurement of volume via displacement).

Practice questions

Free preview — 8 of 40 questions. Sign up to see them all.

1.Which of the following is a scalar quantity?
Easy
- Adistance
- Bdisplacement
- Cvelocity
- Dacceleration
2.Which instrument is most suitable for measuring the thickness of aluminium foil?
Easy
- Aruler
- Btape measure
- Cmicrometer screw gauge
- Dmeasuring cylinder
3.A student measures the time for 20 oscillations of a pendulum as 30.0 s. What is the period of the pendulum?
Easy
- A0.67 s
- B1.5 s
- C10.0 s
- D20.0 s
4.A geologist uses a measuring cylinder containing water to find the volume of an irregular pebble. The water level rises from 40 cm³ to 57 cm³. What is the volume of the pebble?
Medium
- A17 cm³
- B23 cm³
- C40 cm³
- D57 cm³
5.A student wants to measure the volume of a liquid as accurately as possible. Which procedure would make the measurement less accurate?
Medium
- AAligning her eye level with the height of the liquid
- BReading the liquid level from the bottom of the meniscus
- CUsing the largest measuring cylinder she could find
- DUsing a set-square to make sure the cylinder is vertical
6.A boat travels 30 km east then 40 km north. What is the magnitude of its displacement?
Medium
- A50 km
- B70 km
- C10 km
- D1400 km
7.A student uses a stopwatch to time 40 complete swings of a pendulum. The total time is 1 minute 52 seconds. What is the period of the pendulum?
Hard
- A2.8 s
- B1.4 s
- C5.6 s
- D1.9 s
8.Three blocks X, Y, Z are placed in separate measuring cylinders. The water level rises by 10 cm³ for X, 15 cm³ for Y, and 8 cm³ for Z. Which shows the blocks in order of increasing volume?
Hard
- AZ, X, Y
- BX, Y, Z
- CY, X, Z
- DZ, Y, X

More questions

9.Which of the following is a vector quantity?
Easy
- Aspeed
- Bmass
- Cweight
- Dtemperature
10.A student measures the length of a string as 15.6 cm. She then winds it closely around a pen 6 times. What is the circumference of the pen?
Medium
- A2.6 cm
- B2.2 cm
- C13.2 cm
- D15.6 cm
11.A force of 60 N acts to the right and a force of 100 N acts upward on an object. What is the magnitude of the resultant force?
Medium
- A117 N
- B160 N
- C40 N
- D13.6 N
12.An Olympic cyclist rides around a velodrome track 5 times. The stopwatch reads 2 s at the start (due to early start) and 1 min 22 s at the end. What is the average time per lap?
Hard
- A16.0 s
- B16.4 s
- C14.0 s
- D15.2 s
13.A student uses a ruler to measure the length of a metal rod. The ruler has markings every 1 mm. Which reading is recorded to the correct precision?
Medium
- A12 cm
- B12.3 cm
- C12.35 cm
- D12.350 cm
14.A student measures the time for 20 oscillations of a pendulum as 30.0 s. He then measures the time for 10 oscillations of the same pendulum as 15.2 s. Which measurement gives a more accurate value for the period, and why?
Hard
- AThe 20-oscillation measurement, because it has a smaller absolute timing error.
- BThe 10-oscillation measurement, because it is quicker to take.
- CBoth are equally accurate because the period is the same.
- DThe 20-oscillation measurement, because it has a smaller percentage uncertainty.
15.A student uses a measuring cylinder to measure the volume of a liquid. The bottom of the meniscus is at the 25 cm³ mark. The student's eye is above the meniscus. What is the most likely volume reading?
Medium
- A24.8 cm³
- B25.0 cm³
- C25.2 cm³
- D26.0 cm³
16.Which of the following quantities is a vector?
Easy
- AEnergy
- BDistance
- CForce
- DSpeed
17.A student walks 3 km east and then 4 km north. What is the magnitude of the displacement?
Medium
- A5 km
- B7 km
- C12 km
- D25 km
18.A force of 30 N acts east and a force of 40 N acts north on an object. What is the magnitude of the resultant force?
Hard
- A10 N
- B50 N
- C70 N
- D1200 N
19.A student measures the thickness of a single sheet of paper by measuring the thickness of a stack of 100 sheets with a ruler and dividing by 100. The ruler has millimetre markings. The stack thickness is measured as 1.2 cm. What is the thickness of one sheet?
Medium
- A0.012 cm
- B0.12 cm
- C0.012 mm
- D0.12 mm
20.A student wants to measure the volume of an irregularly shaped stone. Which apparatus is most suitable?
Medium
- AA ruler and a balance
- BA measuring cylinder and water
- CA measuring cylinder and a balance
- DA ruler and water
21.Which instrument is most suitable for measuring the length of a football field?
Easy
- ARuler
- BTape measure
- CMicrometer screw gauge
- DVernier calliper
22.A student uses a stopwatch to time a runner over a 400 m track. The start time is 0:12.5 (12.5 s) and the finish time is 1:23.7 (1 minute 23.7 s). What is the time taken to complete the lap?
Hard
- A1 min 11.2 s
- B71.2 s
- C1 min 36.2 s
23.A student uses a ruler to measure the diameter of a ball-bearing. The ball-bearing is placed between two blocks on a ruler. The left block is at 2.0 cm and the right block is at 4.6 cm. What is the diameter of the ball-bearing?
Hard
- A2.6 cm
- B1.3 cm
- C2.0 cm
- D4.6 cm
24.A student measures the length of a string as 15.6 cm. She then winds it closely around a pen 6 times. What is the distance once round the pen?
Medium
- A2.6 cm
- B2.2 cm
- C13.2 cm
- D15.6 cm
25.A student uses a stopwatch to time 40 complete swings of a simple pendulum. The total time taken is 1 minute and 52 seconds. What is the period of the pendulum?
Medium
- A2.8 s
- B1.4 s
- C1.9 s
- D5.6 s
26.A boat travels 30 km due east and then 40 km due north. Which row correctly shows the total distance and displacement magnitude?
Medium
- ATotal distance 70 km, displacement 50 km
- BTotal distance 50 km, displacement 70 km
- CTotal distance 70 km, displacement 70 km
- DTotal distance 50 km, displacement 50 km
27.Three blocks X, Y, Z are placed into three measuring cylinders. The water level rises by 10 cm³ for X, 15 cm³ for Y, and 8 cm³ for Z. Which shows the blocks in order of increasing volume?
Hard
- AZ, X, Y
- BX, Y, Z
- CY, X, Z
- DZ, Y, X
28.A person wishes to roast a chicken. The chicken requires 1 hour and 20 minutes in the oven to be properly cooked. The oven must be switched on 10 minutes before any food is put in, in order to pre-heat, and reach the correct temperature for cooking. The chicken needs to be ready at 4:30 pm. At what time must the oven be switched on?
Medium
- A3:00 pm
- B2:00 pm
- C2:10 pm
- D3:10 pm
29.An Olympic cyclist rides around a velodrome track 5 times. The stopwatch reads 2 s at the start (due to early start) and 1 min 22 s at the end. What is the average time to complete one lap?
Hard
- A16.0 s
- B14.0 s
- C15.8 s
- D15.2 s
30.A student uses a ruler to determine the circumference of a wooden dowel. She puts a mark onto the dowel, then rolls it along the ruler three times, before reading the position on the ruler at which it stopped. The initial mark aligns with 0 cm, and after three revolutions it aligns with 36.9 cm. What is the circumference of the dowel?
Hard
- A12.3 cm
- B12 cm
- C37 cm
- D36 cm
31.A student is timing the rate of cooling of a beaker of water. On a repeat run, the student forgets to zero the stopwatch. The start reading is 0:12.5 (12.5 s) and the end reading is 1:23.7 (1 min 23.7 s). How long did the cooling take?
Hard
- A71.2 s
- B71.2 min
- C1 min 11.2 s
- D1 min 36.2 s
32.A geologist wants to measure the volume of a pebble. She uses a measuring cylinder with water. The initial water level is 40 cm³. After adding the pebble, the water level is 57 cm³. What is the volume of the pebble?
Medium
- A17 cm³
- B6 cm³
- C11 cm³
- D23 cm³
33.Which instrument is most suitable for measuring the thickness of a single sheet of paper?
Easy
- Amicrometer screw gauge
- Bruler
- Cmeasuring cylinder
- Dtape measure
34.A student uses a ruler to determine the circumference of a wooden dowel. She puts a mark onto the dowel, then rolls it along the ruler three times, before reading the position on the ruler at which it stopped. The starting position is 0 cm and the final reading is 36.0 cm. What is the circumference of the dowel?
Hard
- A12.0 cm
- B12.3 cm
- C36.0 cm
- D37.0 cm
35.A geologist wants to measure the volume of a pebble. She uses a measuring cylinder with water. The initial water level is 40 cm³. After adding the pebble, the water level rises to 57 cm³. What is the volume of the pebble?
Medium
- A17 cm³
- B6 cm³
- C11 cm³
- D23 cm³
36.A person wishes to roast a chicken. The chicken requires 1 hour and 20 minutes in the oven to be properly cooked. The oven must be switched on 10 minutes before any food is put in, in order to pre-heat. The chicken needs to be ready at 4:30 pm. At what time must the oven be switched on?
Medium
- A3:00 pm
- B2:00 pm
- C2:10 pm
- D3:10 pm
37.A student measures the time for 20 oscillations of a pendulum as 30.0 s. He then measures the time for 10 oscillations of the same pendulum as 15.2 s. Which measurement gives a more accurate value for the period?
Medium
- AThe first measurement, because more oscillations reduce the effect of reaction time.
- BThe second measurement, because it is quicker.
- CBoth give the same accuracy.
- DThe first measurement, because the time is longer.
38.A student wants to find the volume of a small, irregularly shaped stone. Which pieces of apparatus should the student use?
Medium
- AA measuring cylinder and water
- BA balance and a ruler
- CA measuring cylinder and a balance
- DA ruler and water
39.Which measuring devices are most suitable for determining the length of a swimming pool and the thickness of aluminium foil?
Easy
- ATape measure for length, micrometer screw gauge for thickness
- BRuler for length, measuring cylinder for thickness
- CTape measure for length, ruler for thickness
- DRuler for length, micrometer screw gauge for thickness
40.A student measures the time for 10 oscillations of a pendulum as 15.2 s. The student's reaction time is 0.25 s. What is the approximate percentage uncertainty in the time for one oscillation?
Medium
- A3.3%
- B1.6%
- C16%
- D33%

Slides

Physical Quantities & Measurement Techniques

Physics involves measuring quantities like length, volume, and time.
Different instruments are used depending on the size and precision needed.
Scalars have magnitude only; vectors have magnitude and direction.

Measuring Length

Rulers measure small distances (cm) to the nearest millimetre.
Tape measures measure lengths of tens of centimetres.
Trundle wheels measure lengths of tens of metres.

Which instrument is most suitable for measuring the length of a swimming pool?

Ruler
Tape measure
Trundle wheel
Micrometer screw gauge

Measuring Volume

Measuring cylinders measure the volume of liquids.
The volume of an irregular solid can be found by the change in water level when submerged.
Always read the bottom of the meniscus for accurate measurement.

When measuring the volume of a liquid in a measuring cylinder, you should read the level at the ____ of the meniscus.

Measuring Time

Stopwatches and stop-clocks are used to measure time intervals.
Human reaction time (about 0.25 s) can affect measurements.
Taking multiple readings reduces uncertainty.

A student measures the time for 10 pendulum swings as 15.0 s. What is the time for one swing?

1.5 s
15.0 s
0.15 s
150 s

Multiple Readings & Fiducial Markers

Measuring multiple items (e.g., 100 sheets of paper) and dividing improves accuracy.
For oscillations, measure time for 10 swings then divide by 10.
A fiducial marker (e.g., a line) helps reduce timing errors at the equilibrium point.

Which of these are true about measuring techniques?

Using a larger measuring cylinder always improves accuracy.
Measuring the thickness of 100 pages then dividing by 100 gives a more accurate page thickness.
Human reaction time is typically 0.25 s.

Scalars & Vectors (Extended Tier)

Scalars have magnitude only (e.g., mass, speed, distance).
Vectors have both magnitude and direction (e.g., weight, velocity, displacement).
Distance is scalar; displacement is vector.

Which of the following is a vector quantity?

Speed
Distance
Weight
Energy

Distance vs Displacement

Distance is the total path length (scalar).
Displacement is the straight-line distance from start to finish, including direction (vector).
Example: walking 3 km east then 4 km north gives distance 7 km, displacement 5 km northeast.

A person walks 30 m east then 40 m north. The total distance is ____ m and the displacement magnitude is ____ m.

Calculating with Vectors (Extended Tier)

Vectors can be added graphically using scale drawings.
For perpendicular vectors, use Pythagoras to find resultant magnitude.
Use trigonometry (tan) to find direction.

Two forces act at right angles: 60 N east and 80 N north. What is the magnitude of the resultant force?

100 N
140 N
20 N
120 N

Graphical Vector Addition

Choose a scale (e.g., 1 cm = 10 N).
Draw vectors tip-to-tail, then draw resultant from start to finish.
Measure length and angle with ruler and protractor.

A boat travels 30 km east then 40 km north. What is the displacement magnitude?

70 km
50 km
10 km
1400 km

Common Scalar-Vector Pairs

Distance (scalar) vs Displacement (vector)
Speed (scalar) vs Velocity (vector)
Mass (scalar) vs Weight (vector)

Which of these are scalar quantities?

Mass
Velocity
Energy
Acceleration

Unlock all 40 questions, slides & more

Create a free account to see every question, the slides, flashcards and revision notes for this topic.

Past papers

Past-paper practice for this topic is coming soon.

🗂️ Coming soon