1. What is Porosity?

Definition: Porosity (φ) is a measure of the void spaces in a material, expressed as a fraction of the total volume.

Purpose: It's important in geology, soil science, and materials science for understanding fluid storage and flow through porous media.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \phi \) — Porosity (unitless, between 0 and 1)
• \( \rho_{bulk} \) — Bulk density of the material (kg/m³)
• \( \rho_{particle} \) — Particle density of the material (kg/m³)

Explanation: The ratio of bulk to particle density gives the solid fraction, so subtracting from 1 gives the void fraction (porosity).

3. Importance of Porosity Calculation

Details: Porosity affects water retention, permeability, strength, and thermal properties of soils and construction materials.

4. Using the Calculator

Tips: Enter the bulk density (mass of dry material divided by total volume) and particle density (default 2650 kg/m³ for quartz). Bulk density must be less than particle density.

5. Frequently Asked Questions (FAQ)

Q1: What are typical porosity values?
A: Soils: 0.3-0.6, sandstones: 0.1-0.4, clays: 0.4-0.7, gravels: 0.2-0.4.

Q2: What's a typical particle density?
A: For mineral soils: ~2650 kg/m³ (quartz). Organic matter has lower density (~1300 kg/m³).

Q3: How do I measure bulk density?
A: Weigh a known volume of dry material (core sample) after removing any compaction.

Q4: Why is my result negative?
A: Bulk density cannot exceed particle density. Check your measurements if this occurs.

Q5: How does porosity relate to void ratio?
A: Void ratio (e) = φ/(1-φ). Porosity is void volume/total volume, void ratio is void volume/solid volume.