Surface Area & Volume Relationships: Sphere, Cone, and Cylinder
What you will learn
Verify Archimedes' ratio of volumes and surface areas between a cone, a sphere, and a cylinder having identical radius (r) and height (h = 2r) using dry fine sand displacement.
Materials needed
- Hollow transparent acrylic geometric models: Cylinder (radius r = 5 cm, height h = 10 cm), Sphere (radius r = 5 cm with top aperture), Cone (radius r = 5 cm, height h = 10 cm) setWhat is it?Hollow transparent acrylic geometric models: Cylinder (radius r = 5 cm, height h = 10 cm), Sphere (radius r = 5 cm with top aperture), Cone (radius r = 5 cm, height h = 10 cm) set₹50
Set of hollow transparent acrylic geometric solids sharing identical radius r = 50 mm and height h = 100 mm.
Specifications- Solids Included
- Right circular cone, cylinder, full sphere, hemisphere
- Wall Thickness
- 2.5 mm optical clear acrylic
- Lid Openings
- Removable fill caps on all bases
- Calibration
- Exact 1:2:3 volumetric ratio matched
- Fine dry colored sand or water kgWhat is it?Fine dry colored sand or water kg₹95
Fine dry quartz test sand (graded mesh 50-70) colored with non-toxic pigment.
Specifications- Particle Size
- 0.2 – 0.3 mm uniform quartz grains
- Flowability
- Free-flowing dry granular bulk density 1.55 g/cm³
- Quantity
- 2.0 kg in plastic pour container
- Measuring Flask (1000 mL)What is it?Measuring Flask (1000 mL)₹140
Graduated 1000 mL Class A measuring cylinder for volumetric liquid cross-check.
Specifications- Capacity
- 1000 mL
- Graduation
- 10 mL subdivisions
- Material
- Polypropylene chemical/shatter resistant
- Plastic funnel and collection trayWhat is it?Plastic funnel and collection tray₹185
Standard laboratory apparatus used in Surface Area & Volume Relationships: Sphere, Cone, and Cylinder.
Specifications- Category
- Mathematics Apparatus
- Grade
- CBSE / NEP 2020 Laboratory Standard
- Leveling straightedge rulerWhat is it?Leveling straightedge ruler₹230
Standard laboratory apparatus used in Surface Area & Volume Relationships: Sphere, Cone, and Cylinder.
Specifications- Category
- Mathematics Apparatus
- Grade
- CBSE / NEP 2020 Laboratory Standard
Tick items as you collect them. Tap + to see the product, specifications and buy options.
Stay safe
- Ensure sand is completely dry and free of clumps to ensure uniform packing density.
- Always level the sand rim with a flat straightedge; avoid packing or shaking vigorously between fills.
- Pour sand through a funnel slowly into the models to avoid spilling outside the measurement rim.
- Wipe acrylic models with anti-static cloth to prevent sand grains sticking to walls.
Steps
- 1Verify dimensions of acrylic solids: cylinder height h = 10 cm, radius r = 5 cm; cone height h = 10 cm, radius r = 5 cm; sphere diameter 2r = 10 cm.Observation
Inspect hollow transparent plastic shapes: cone, hemisphere, sphere, and cylinder sharing identical radius r = 5.0 cm and height h = 10.0 cm.
SafetyCheck plastic shapes for cracks or leaks before filling with liquid/sand.
- 2Fill the hollow cone completely with fine sand and level off flush with the rim using a straightedge.Observation
Fill hollow cone to the brim with fine colored dry sand; level top surface with a straight ruler edge.
SafetyPour sand over plastic tray to catch any spills.
- 3Pour the sand from the cone into the empty cylinder. Observe that it fills exactly 1/3 of the cylinder's volume.Observation
Pour sand from cone into cylinder: exactly one-third of cylinder is filled.
SafetyTap cylinder base lightly to settle sand evenly.
- 4Fill the cone two more times into the cylinder: three full cones exactly fill the cylinder (V_cylinder = 3 × V_cone = 3 × (1/3 πr²h) = πr²h).Observation
Pour second full cone of sand into cylinder: cylinder is now two-thirds full.
SafetyEnsure cone is filled completely flush with brim each time.
- 5Now empty the cylinder. Fill the hollow sphere model with fine sand.Observation
Pour third cone of sand into cylinder: sand reaches the absolute brim of the cylinder, proving V(Cylinder) = 3 × V(Cone).
SafetyZero sand remains left over; cylinder is filled to 100% capacity.
- 6Pour the sphere's sand into the empty cylinder: it fills exactly 2/3 of the cylinder (V_sphere = 2/3 V_cylinder = 4/3 πr³).Observation
Fill hollow sphere with 2 full measures of the cone, proving V(Sphere) = 2/3 V(Cylinder) = 4/3 πr³.
SafetyReturn dry sand to storage hopper and wipe transparent models with microfiber cloth.
- 7Combine one full cone of sand and one full sphere of sand: together they fill the cylinder 100% full.
Tap + on a step to see what you will observe and any safety tips.
Record your observations
| Geometric Solid Body | Theoretical Formula (h = 2r = 10 cm) | Volume Calculated (cm³) | Sand Filling Measure (Scoops) | Volume Ratio to Cylinder |
|---|---|---|---|---|
| Cone (r = 5 cm, h = 10 cm) | V = 1/3 · π · r² · h = 1/3 × π × 25 × 10 | 261.80 cm³ | 1 scoop (Base unit 1.0) | 1 / 3 (33.3% of cylinder) |
| Sphere (r = 5 cm, d = 10 cm) | V = 4/3 · π · r³ = 4/3 × π × 125 | 523.60 cm³ | 2 scoops (Exactly 2× cone) | 2 / 3 (66.7% of cylinder) |
| Cylinder (r = 5 cm, h = 10 cm) | V = π · r² · h = π × 25 × 10 | 785.40 cm³ | 3 scoops (Exactly 3× cone) | 3 / 3 (100% full capacity) |
Tap a highlighted cell to write your own observation.
Result and conclusion
Empirically verified that Volume of Cone : Volume of Sphere : Volume of Cylinder = 1 : 2 : 3. Sand from one cone and one sphere exactly fills the circumscribed cylinder without spill.
| Observation | What it means |
|---|---|
| Archimedes Epitaph Ratio 1:2:3 | Archimedes regarded this discovery as his crowning triumph: for a cylinder circumscribed around a sphere and cone (h = 2r), their volumes are strictly 1 : 2 : 3. |
| Experimental Volumetric Proof | Exactly 3 full measures of the cone fill the cylinder to the brim (V_cyl = 3 · V_cone). |
| Sphere to Cone Equivalence | Pouring 2 full measures of the cone fills the hollow sphere completely (V_sphere = 2 · V_cone = 4/3 πr³). |
| Surface Area Relationship | Total surface area of sphere (4πr²) equals the curved surface area of the circumscribed cylinder (2πr·h = 2πr·2r = 4πr²). |
Sample readings. Replace with your own results.