DRY MASS—
INITIAL / FINAL WATER— / —
Begin with the balance.
Identify the metal.
Weigh an unknown. Displace water. Compare density with reference values.
Lab options
Your next action
YOUR MISSION
Can measurements identify an irregular solid?
Your sample is one of three model candidates: aluminum, steel, or copper. Measure its mass and use displaced water to find its volume.
Repeat the full measurement three times on the same sample, drying it before each weighing. Compare your mean density with the reference table at the end.
Mass ÷ volume = densityBalance: 0.01 gCylinder: 0.1 mL
This model assumes a nonporous, insoluble sample at 20°C. It sinks and can be fully submerged without bubbles. Reference values are fixed for these candidates, not universal values for every alloy.
How does displacement measure volume?
Read the bottom of the water’s meniscus at eye level before and after fully submerging the sample. The rise in volume equals the sample volume in this model: final reading − initial reading. One milliliter is one cubic centimeter.
Density = dry mass ÷ displaced volume. Dividing grams by milliliters gives g/mL, numerically equal to g/cm³. The app supports the calculation; you can check one yourself at the end.
A wet sample would add water to the measured mass. A bubble stuck to the sample would displace extra water. The guide helps you follow the procedure, but this simulation does not model bubbles or residual surface water.
Your measurement record
| Trial | Dry mass (g) | Initial (mL) | Final (mL) | Displaced (mL) | Density (g/cm³) |
|---|
These are repeat measurements of one sample, not three independent pieces of metal.
3 / IDENTIFY WITH EVIDENCE
Which candidate best matches your measurements?
Compare your mean and range with the model reference values. A close match supports an identification among these candidates; it is not proof of chemical composition.
MEAN DENSITY
OBSERVED RANGE
| Candidate | Reference density (g/cm³) |
|---|---|
| Aluminum | 2.70 |
| Steel | 7.85 |
| Copper | 8.96 |
The minimum–maximum range describes your three readings, not a confidence interval. Similar density does not uniquely establish a real material’s identity.
Help me explain my results
Measurements from your investigation
These are your recorded model results. Choose the evidence that supports your own conclusion.
- Make a claim.
- Use evidence.
- Explain the science.
- Set a limit.
Before downloading: Does your explanation answer the question, use a number with units, explain why, and state a limit? Revise it above if needed.
This guide does not write or grade your explanation. A teacher reviews your scientific reasoning.
Optional calculation: density from trial 1
Choices and the optional calculation are checked automatically. A teacher reviews the scientific reasoning in your explanation.