Physical Property of Matter | Overview & Examples

In chemistry, density can be defined by the mass of a unit volume of a material substance. Density can be expressed by variable {eq}d {/eq} and can estimated using the following formula: {eq}d = M / V {/eq}. Where {eq}d {/eq} is density, where {eq}M {/eq} is mass, and where {eq}V {/eq} is volume. Density is generally expressed in units of grams per cubic centimeter, although density can also be expressed in units of kilograms per cubic meter. Density is classified as an intensive property. Even though both mass and volume are extensive properties, density is a ratio of these two properties, and the ratio does not change. Therefore, density is categorized as an intensive property.

Referring back to the water example, the density of water may change according to its state of matter and associated properties. For example:

• Density of water (at 4 degrees Celsius) = 1.000 {eq}(g/cm^3) {/eq}, with the state being liquid

• Density of water (at 20 degrees Celsius = 0.998 {eq}(g/cm^3) {/eq}, with the state being liquid

• Density of ice = 0.920 {eq}(g/cm^3) {/eq}, with the state being solid

• Density of water vapor = 0.76 {eq}(g/cm^3) {/eq}, with the state being vapor

Odor can be defined as a distinctive smell, sometimes an unpleasant one. Odor is classified as a physical property of matter as it is an observable trait that won't change the identity of a substance. In addition, odor is known to be an intensive property because it does not depend on the quantity of matter. Natural odors may be described as earthy, musty, sour, or even fishy, grassy, or herbaceous. Industrial odors often smell like iodine, petroleum, varnish, alcohol, or even medicine. Some well-known examples of odors are as follows:

• Fragrances (florals, perfumes)
• Fruity (non-citrous)
• Citrus (lemon, lime, orange)
• Woody (pine, grass)
• Chemicals (bleach)
• Sweet (chocolate, caramel, vanilla)
• Minty (peppermint, eucalyptus)
• Nutty (peanut butter, almonds)
• Pungent (blue cheese, cigar smoke)
• Decayed (sour milk, rotting food)

Color is another example of a physical property, as it can be determined without changing the composition of a substance. More specifically, color is another intensive property. Here are some examples of the color of some naturally occurring matters:

• Green (vegetation, grass, trees)
• Blue (ocean, water, sky)
• Pink (flowers)
• Red (rose, blood)
• Yellow (sun)
• White (snow, sand)

Hardness is another example of a physical property it is categorized as an intensive property. Hardness of matter can be defined by the ability of a material to resist fracture, deformation, or permanent indentation when a load is applied. Hardness can be expressed in Pascal units, also written as {eq}N/mm^2 {/eq}. Hardness is dependent on ductility, elasticity, stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity, and the property itself can be tested through various methods such as indentation tests. Outlined below are examples of the hardness of some forms of matter:

• Ceramics
• Concrete
• Certain metals (iron)
• Glass
• Plastic

Length is another example of a physical property, more specifically an extensive property. The unit of length refers to any arbitrarily chosen and accepted reference standard for measurement. Length can be expressed in various units of measurement but is most commonly measured by metric units, for example, in millimeters (mm), centimeters (cm), meters (m), kilometers (km), etc. Length can also be measured via imperial units which include inches, feet, yards, and miles. Length as a physical property refers to the longest dimension of an object. Some examples of the length of some matters are listed below:

1 mm = the thickness of a staple

1 cm = the width of a little finger

1 m = the width of a doorway

1 km = approximately 6 city blocks

Melting point is another physical property. In fact, it is classified as an intensive property. Melting point can be defined by the temperature at which a given solid will melt. To elaborate, when the melting point of a substance has been reached, the solid and liquid phases exist in equilibrium. In addition, the melting point of substances depends upon pressure and can vary depending on the substance. The melting point units are expressed through various units, most commonly including Kelvin {eq}[K] {/eq}, degrees Celsius, degrees Fahrenheit, or even degrees Newton.

Listed below are some examples of the various melting points for different matters:

• Water = 0 degrees Celsius
• Nitrogen = -209.9 degrees Celsius
• Silver = 961.93 degrees Celsius
• Carbon = 3500.0 degrees Celsius

Volume is another physical property and can be defined as a quantity that expresses the amount of 3D space enclosed by a closed surface. It is an extensive property. A unit of volume is used to measure the capacity of the object or space occupied and can be measured in cubic units, for example, {eq}cm^3 {/eq} when referring to a solid, or metric units when referring to a liquid, for example; milliliters (mL), centiliters (cL), deciliters (dL), or even liters (L). Here are some examples of volumes of some matters:

1 measuring cup = 250mL

1 milk jug = 3.78L

1 basketball = 33.5{eq}cm^3 {/eq}

1 bathtub = approximately 302L

Properties of a substance are used to describe its different characteristics and can be classified as either physical or chemical. Physical properties are what can be observed without the substance identity being altered; therefore the physical change is reversible. Some examples of physical properties include color, hardness, conductivity, density, etc.

In addition, physical properties can be broken down into intensive or extensive. Intensive properties are not dependent on the quantity of matter (example: odor), whereas extensive properties are (example: volume). Overall, physical properties are critical for scientists to measure, observe, describe, and better understand matter.