PROPERTIES OF MATTER
The Properties of Matter course explores the fundamental characteristics that define and distinguish materials, focusing on both physical and mechanical attributes. Key concepts include density, which explains why oil floats on water; pressure, as seen in how sharp knives cut more effectively due to higher pressure over smaller areas; and elasticity, which is crucial in designing springs and shock absorbers. The course also covers floatation using Archimedes’ Principle, which helps explain how ships float despite their massive weight. Additionally, it examines surface tension, observable when insects like mosquitoes walk on water, and viscosity, which influences the flow of engine oils in automobiles.
1. INTRODUCTION
1.0 INTRODUCTION
Properties of matter are the characteristics or attributes of a substance that help define and distinguish it from other substances. These properties can be observed or measured and are classified into physical properties (which do not change the substance’s identity) and chemical properties (which describe how a substance interacts with other substances and changes composition).
1.1 Density
1.1.1 Density is a property of matter. It tells us about how concentrated the matter is in a particular material. Density is a constant for a given material under specific conditions. Density is defined as the mass per unit volume of a substance.
Density = mass/volume ρ = m/v
The symbol used here for density, ρ, is the Greek letter rho.
The standard unit for density in the SI system is kgm−3, but you may also find values quoted in gcm−3.
It is useful to remember that these units are related by: 1000 kgm−3 = 1 gcm−3 and that the density of water is approximately 1000 kgm−3.
1.1.2 Mass: is the measurement of the amount of matter in an object. It is typically measured in kilograms (kg) or grams (g) and remains constant regardless of location, unlike weight, which depends on gravity.
Volume is the amount of space that a substance or object takes. It is measured in units such as liters (L), cubic meters (m³), cubic centimeters (cm³), or milliliters (mL)
1.1.3 Examples
1. A cube of copper has a mass of 240g. Each side of the cube is 3.0cm long. Calculate the density of cop per in gcm−3 and in kgm−3. (Surface Area)
2. The density of steel is 7850kgm−3. Calculate the mass of a steel sphere of radius 0.15m.