[Physics Class Notes] on Properties of Wood Pdf for Exam

Wood is the second most used material for construction purposes, making of furniture, flooring, etc. For building constructions, though the stone has taken first place, the boom of wood has increased dramatically in recent times. Let’s see more interesting facts about wood, different physical, chemical, mechanical, properties of wood.

Tissue Composition of Wood

Wood is a natural resource that can be obtained by plants and trees. Basically wood is a combination of different tissues like the xylem, which is a vascular tissue, phloem, and cell walls. The vascular cambium layer which is present inside the bark helps to produce new wood.

Properties of Wood

The properties of wood explain its behaviour, and how it reacts to different substances at different temperatures. These properties explain the characteristics of wood with a generalized meaning. The properties of wood may include physical properties, chemical properties, mechanical properties. The physical properties of wood can be defined as the characteristics of a wood that do not have any change in its size, shape, colour, etc.

Physical Properties of Wood

The characteristics of wood that explain the physical features of various types of wood are nothing but the physical properties of wood. They are explained as follows.

Colour – As the basic use of wood is to make furniture and decor items for the house, colour and appearance play a vital role in choosing a variety of wood. But the colour of the wood varies from type to type. The wood is available in a wide range of colours starting from white to dark brown etc. The colour of the wood also changes with the observation. If a tree can be observed from top to bottom, it appears in some colour and vice versa.

Lustre – Another physical property of wood is its lustre. Luster refers to the tendency of elements with the reflection of light. After colour, priority is given to the lustre of the wood.

Odour and Taste – We commonly observe different odours from different types of wood. For example, the sandalwood and the rosewood give a nice aroma whereas the other timber woods may give some tobacco odour. Also, the new wood sample gives a fresh aroma and it keeps on degrading with time.

The density of Wood – Another characteristic of wood is its density. But what is the density of wood? The density of wood refers to its mass per unit volume. Based on the weight of the wood sample, the density of wood changes. Different types of wood have different densities. Below detailed information about the density of different types of wood is given.

• If the density or specific gravity is 36 then the wood is called very light.

• When density or specific gravity is = 0.36 then the wood is called light.

• If the density or specific gravity is 0.36 – 0.05, then wood is considered moderately heavy.

• When density or specific gravity is > 0.05, then the wood is heavy.

Hardness – Hardness refers to the strength of the wood also the resistance or the capacity of wood which can stand strong for a long time after being affected by several factors. 

Mechanical Properties of Wood

The mechanical properties of wood can be explained as the capability of wood to withstand externally applied forces. These include different types of properties to understand the strength, resistivity, elasticity, durability, etc. many more characteristics of wood. The mechanical properties of wood were further classified into two. One is strength properties and the other is elasticity properties. There are different standards available to check the strength of wood. They are – 

• ISO (International standard institution

• ISI (Indian standard Institution)

• BSI (British Standard Institution)

• PSI (Pakistan Standard Institution)

Compression – The compression of wood depends on the directions of applied forces, like – 

• perpendicular to wood grain

• parallel to wood grain, and 

• an angle to the wood grain.

Tension –  The tension is very effective on wood when it is parallel to the wood’s grain.

Bending – Based on the load put on the wood, bending may occur. It shows the strength and stability of wood even if the load is increased in a parallel direction.

Conclusion

Wood is one of the most important materials used for several household and commercial purposes. Different types of physical properties and mechanical properties of wood explain the characteristics of a particular type of wood. All these properties were generalized to all types of wood. Few differences may occur accordingly.