Materials are the set of elements that are needed for specific tasks or activities. Normally these tasks tend to be construction works or manufacturing of objects.
A characteristic case of the notion of materials is when talking about components used in constructions. For example, bricks, cement, tools of different types, plaster, wood, metals, electrical components, among others, are usually considered materials.
All these materials used together serve to repair or build certain places or spaces and are always basic elements that every builder or bricklayer has to have.
The properties of materials are divided into specific and general.
General properties are common characteristics in almost all substances and specific properties refer to one or a small group of substances.
Characteristics of Material
Characteristics of materials refer to the specific qualities and properties that define and distinguish different types of materials. These characteristics are important for understanding how materials behave and interact in various applications and environments. Here are some key characteristics of materials:
- Physical properties: These properties describe the physical attributes of a material, such as its color, density, texture, and shape. For example, metals like gold and copper have a shiny appearance, while plastics can have a wide range of colors and textures.
- Mechanical properties: Mechanical properties refer to how a material responds to external forces, including its strength, hardness, toughness, elasticity, and ductility. For instance, steel is known for its high strength and toughness, while rubber is highly elastic and flexible.
- Thermal properties: Thermal properties describe how a material responds to changes in temperature. These properties include thermal conductivity, specific heat capacity, and coefficient of thermal expansion. For example, metals like copper and aluminum have high thermal conductivity, making them good conductors of heat.
- Electrical properties: Electrical properties define how well a material conducts electricity or resists the flow of electrical current. These properties include electrical conductivity, resistivity, and dielectric strength. Copper is a good conductor of electricity, while materials like rubber and plastic are insulators.
- Chemical properties: Chemical properties describe how a material interacts with other substances and undergoes chemical reactions. These properties include reactivity, corrosion resistance, and chemical stability. For instance, metals like stainless steel are highly resistant to corrosion, while certain plastics are chemically inert.
- Optical properties: Optical properties pertain to how a material interacts with light, including its transparency, reflectivity, and refractive index. Glass is transparent and allows light to pass through, while metals are highly reflective.
It is important to note that these characteristics can vary widely among different materials and can be modified through processes such as alloying, heat treatment, and surface coatings. Understanding the characteristics of materials is crucial for selecting the right material for a specific application and predicting its behavior under different conditions.
General properties
Extension
The extension is all the space occupied by the matter .
Inertia
It is a property responsible for preserving the movement or rest of matter in a uniform and straight way. It is important to know that the greater the mass, the greater the inertia, since mass is considered the measure of inertia.
Impenetrability
This property refers to the fact that two bodies cannot occupy the same space at the same time.
For example, if we fill a bathtub with water to the surface, and then step into it, the water in the bathtub will overflow.
Divisibility
This property refers to the division of small particles of matter, without losing its characteristics or properties.
Example:
- Sugar dissolved in water.
- Water distributed in various containers.
Compressibility
This property refers to the decrease in the volume of a body. Gases are the easiest to compress .
Specific properties
Melting point (PF)
The melting point is the temperature at which a material goes from a solid state to a liquid state. The melting point temperature of each material varies.
Look at the examples (at 1 atm):
- Nitrogen: FP = – 210ºC.
- Common alcohol: FP = – 143ºC
- Water: FP = 0ºC
- Sodium chloride: FP = 801ºC
Boiling point (PE)
The boiling point is the temperature at which a material goes from the liquid state to the gaseous state. The boiling point temperature of each material varies.
Observe the following examples (at 1 atm):
- Nitrogen: FP = – 196ºC.
- Common alcohol: FP = – 78ºC
- Water: FP = 100ºC
- Sodium chloride: FP = 1490ºC
Absolute density or specific mass
As we can see in the previous formula, density is considered mass divided by volume. Remembering that the unit of measurement of its mass is g / cm3.
Let’s look at an example:
- If we place a stone inside a glass full of water, the stone will sink, because the stone is denser than water.
Hardness
This property measures the resistance of the materials. To know if one material is harder than another, a friction test is necessary.
Note: Diamond is the most resistant substance that exists.
Example:
Let’s imagine a wood and a steel knife. This knife will scratch wood, so it is more resistant, but if we use quartz instead of wood, we will notice that it is stronger than the steel knife since it does not scratch the quartz.
Malleability
Malleable materials can be reduced to sheets, such as silver, gold, zinc, among others.
Ductility
This property refers to the fact that materials can be transformed into threads, such as aluminum, copper, among others.
Solubility
This property refers to materials that dissolve and those that do not dissolve, that is, they are homogeneous mixtures and heterogeneous mixtures .
Example:
If you add a small amount of sugar to a glass of water, the sugar dissolves completely, making it a homogeneous mixture, but if you add sand to a glass of water, no matter how small the amount is, it will not dissolve, so it will be treated. of a heterogeneous mixture.
In 100g of water there can be 220g of sugar, if the water is heated to 30ºC and if we try to dissolve more than 220g of sugar the excess will remain deposited at the bottom of the container.
The matter that dissolves in the maximum amount is called the solubility coefficient. This matter depends on the temperature, because when we have 100 grams of water at a temperature of approximately 50ºC, only 260 grams of sucrose will be able to dissolve. This explains the fact that coffee is made only in hot water, since it is not soluble in cold water.
Organoleptic properties
They are properties capable of activating our senses. Consider the following:
- Color is perceived by vision, for example, the forest is green .
- Shine is also perceived by vision, for example , polished metal (reflects light).
- The flavor is perceived by the palate, for example, sugar is sweet.
- The smell is perceived by the sense of smell, for example, water is odorless.
Physical properties are capable of identifying some aspects, such as boiling point, melting point, density, etc.
Chemical properties generally do not identify these aforementioned aspects, since a chemical reaction must occur.
The Intensive Physical Property does not depend on the material, such as flavor, color, transparency, among others.
The Extensive Physical Property depends on the quantity of the material, such as mass.