Lesson 1.7 • Competency 1.4Interactive Simulation

Practical Laboratory Investigations

Interactive virtual laboratory covering all 5 official NIE Grade 12 practicals: (1) Vernier Calipers (Hollow Cylinder), (2) Micrometer Screw Gauge (Coin), (3) Spherometer (Radius of Curvature), (4) Travelling Microscope (Rubber Tube), (5) Density of Regular Solid.

Marking a lesson complete represents finishing your study of the topic; it does not denote tested mastery.

Learning Objectives

Execute laboratory protocols, record structured observations, and apply zero error corrections.
Analyze sample data and compute material volume, curvature radius, tube radii, and solid density.
Propagate fractional uncertainties and generate printable laboratory records.

Core Theory & Concepts

Practical laboratory work is the cornerstone of G.C.E. A/L Physics. Unit 1 features 5 prescribed investigations that teach measurement rigor, instrument zero correction, repeated sampling, and uncertainty propagation.

Practical 1: Hollow Cylinder

Measure external diameter D (lower jaws), internal diameter d (upper jaws), and depth h (depth probe). Volume of material: V = π(R² - r²)h.

Practical 2: Coin Dimensions

Use ratchet to prevent coin deformation. Measure diameter across 3 directions to account for eccentricity. Volume V = π(D/2)²t.

Practical 3: Spherometer Curvature

Measure leg spacing a on paper pricks. Obtain plane zero h₀ on glass. Measure curved elevation h₁. Formula: R = (a² / 6h) + (h / 2).

Practical 4: Travelling Microscope Tube

Traverse horizontally in ONE direction to prevent backlash error. Record x₁, x₂, x₃, x₄. d_int = x₃ - x₂, d_ext = x₄ - x₁, thickness t = (d_ext - d_int)/2.

Practical 5: Solid Density

Select balance for mass and vernier/micrometer for dimensions. Density ρ = m/V. Convert g cm⁻³ to kg m⁻³ by multiplying by 1000.

Syllabus Topic Outline

Competency 1.4

1Practical 1: Vernier Calipers – hollow cylinder dimensions & volume
2Practical 2: Micrometer Screw Gauge – coin diameter and thickness
3Practical 3: Spherometer – spherical mirror/lens radius of curvature
4Practical 4: Travelling Microscope – rubber tube internal and external radii
5Practical 5: Density of Regular Solid – mass, volume, and unit conversions

A/L Physics Laboratory: Unit 1 Practicals Hub

Complete hands-on virtual laboratory practicals for official NIE Grade 12 investigations (Handbook Exp 1–4 and Additional Solid Density).

Practical 1: Internal/External Radii & Material Volume of a Cylinder

Aim: To determine the internal and external radii, external height, internal cavity depth, and volume of the material of a cylinder using Vernier Calipers.

Apparatus: Vernier Calipers (Least Count 0.1 mm), Cylindrical specimen (Closed-bottom calorimeter vessel or open hollow pipe).

Underlying Theory & Distinctions (Radius vs. Diameter, Tube vs. Closed Vessel)

Vernier calipers measure diameters directly: outside jaws measure external diameter D, inside jaws measure internal diameter d, and the depth probe measures cavity depth h. The corresponding radii are calculated by halving: External Radius R = D / 2 and Internal Radius r = d / 2. For an open hollow pipe (length H), solid volume is V_solid = π(R² - r²)H. For a closed-bottom cylinder (e.g. calorimeter vessel with external height H and internal depth h), the base thickness is t_base = H - h, and material volume is V_solid = πR²H - πr²h. Zero error correction: Corrected = Observed - (Signed Zero Error).

Procedure: 1. Determine least count and check zero error. 2. Measure external diameter D at 3 orientations. 3. Measure internal diameter d using internal jaws. 4. Measure external height H with outside jaws. 5. If closed-bottom, measure internal depth h with the depth probe. 6. Correct for zero error, compute radii (R = D/2, r = d/2), and calculate material volume.

Learning Mode:

Vernier Calipers Simulator

10-division Vernier (Least Count: 0.1 mm)

Jaw Opening: 24.6 mm

Fine Stepping24.6 mm

Zero Error (e)0.0 mm

Corrected = Observed - (Zero Error)

High-Precision Vernier View (Coincidence Detector)

MSR = 24 mm | Coincident Vernier division = Division #6 (6 × 0.1 = 0.60 mm).

Self-Check Reading

Transfer Instrument Reading to Table:24.6 mm

Observation & Measurement Table

Specimen Geometry:

Zero Error (signed, mm):

Parameter	Mean Observed (mm)	Corrected Value (mm)
External Diameter (D) [Outside Jaws]	—	—
Internal Diameter (d) [Inside Jaws]	—	—
External Height (H) [Outside Jaws]	—	—
Cavity Depth (h) [Depth Probe]	—	—

Calculated Results & Material Volume

External Radius R = D / 2:—

Internal Radius r = d / 2:—

Base Thickness t_base = H - h:—

Hollow-Cylinder Capacity V = π(d/2)²h:—

Solid Material Volume (V_solid):—

Laboratory Precautions & Self-Evaluation RubricsSelf-Evaluation Rubric Score: 0 / 6

1. Why must diameter measurements be taken across mutually perpendicular orientations?

Model Answer: Cylindrical specimens often possess slight elliptical deformities or imperfections. Taking diameters along perpendicular axes and computing the arithmetic mean eliminates non-circularity bias.

Rubric: Award 1 mark for mentioning elliptical cross-section / non-circularity; 1 mark for stating that mean averages out discrepancy.

Mark Awarded:

2. Explain the physical distinction between positive and negative zero error.

Model Answer: If the vernier zero lies to the right of the main scale zero when jaws are closed, zero error is positive (reads too high, so subtract). If to the left, zero error is negative (reads too low, subtracting negative error adds the magnitude).

Rubric: Award 1 mark for relative zero mark position; 1 mark for correct mathematical sign application.

Mark Awarded:

3. Why must excessive tightening force be avoided when closing the jaws?

Model Answer: Excessive force deforms soft specimens and strains the caliper jaws/slide mechanism, causing systematic zero shifts and damaging the precision scale.

Rubric: Award 1 mark for specimen deformation; 1 mark for caliper jaw strain/zero shift.

Mark Awarded: