The density of pure lead is 11,340 kg/m³ or 11.34 g/cm³ at standard room temperature (20°C or 68°F).
Lead is a remarkably dense metal, a property that makes it invaluable for various industrial and scientific applications. Its high density is a primary reason for its effectiveness in applications requiring significant mass in a compact space, such as radiation shielding and ballasting. Understanding this fundamental property is crucial for engineers, designers, and anyone working with this versatile element.
Understanding Lead's Density
Density is a measure of mass per unit volume. For lead, this value indicates how much mass is packed into a given space. The specific conditions, such as temperature, are important when stating density, as materials expand or contract with temperature changes, slightly altering their density. The standard reference temperature of 20°C (68°F) ensures consistent measurements.
Key Density Values for Pure Lead
Here's a quick overview of lead's density in commonly used units:
| Unit System | Density Value | Conditions |
|---|---|---|
| Metric (SI) | 11,340 kg/m³ | 20°C (68°F) Room Temperature |
| Metric (CGS) | 11.34 g/cm³ | 20°C (68°F) Room Temperature |
These values highlight lead's significant weight compared to many other common metals. For comparison, the density of water is approximately 1,000 kg/m³ (1 g/cm³), meaning lead is more than eleven times denser than water.
Factors Affecting Lead Density
While the density of pure lead is a specific value under standard conditions, several factors can influence it slightly:
- Temperature: As temperature increases, materials typically expand, causing their density to decrease. Conversely, cooling lead will slightly increase its density.
- Purity: The presence of impurities or alloying elements can alter lead's density. For instance, an alloy of lead with a less dense metal would result in a lower overall density. The value provided is specifically for pure lead.
- Pressure: Although less significant for solids under typical conditions, extreme pressure can marginally compress a material, leading to a slight increase in density.
Practical Applications of High Density
Lead's high density is its most defining characteristic, leading to its use in a wide array of applications:
- Radiation Shielding: Its ability to absorb X-rays and gamma rays effectively makes lead indispensable in medical facilities, nuclear power plants, and for protective equipment. The dense atomic structure of lead is highly effective at attenuating high-energy radiation. Learn more about lead's role in radiation shielding.
- Ballasts and Weights: From fishing weights and dive belts to keel weights in ships and counterweights in heavy machinery, lead's density provides a compact solution for adding mass.
- Ammunition: Lead's high density and relatively low melting point make it suitable for bullets and shot, providing significant kinetic energy upon impact.
- Soundproofing: Its mass helps to block sound transmission, making it useful in certain soundproofing applications.
Understanding the density of lead allows for precise calculations in engineering and design, ensuring the safety and effectiveness of products and structures that rely on this unique metal.
