Basic Technology, JSS 1, Week: 9
Topic:Identification of Ceramics, Plastics and Rubber
Many kitchens and household containers are made from clay and cement. These include cooking pots, water pots, etc. Clay and mud are also used in some places to make houses. The items made clay and mud are called ceramics.
Ceramics break easily when they are dropped forcefully. This means they are brittle. This makes ceramics different from plastic, wood, metal and rubber.
Plastics are also materials used to mould household containers. Plastics can be made in different ways. It can be made as hard as stone, as strong as steel, as transparent as glass, as light as wood, and as elastic as rubber. Plastics are usually light weight and come in different colors.
Types of plastics
There are two types of plastics – thermoplastics and thermosets.
Thermoplastics: They are the plastics that become soft and flow like a thick liquid when they are heated. They can therefore be remoulded. Most of the plastic containers that we use at home are in this group.
Thermosets: They are the plastics that we cannot soften to liquid by heating. Examples are the buttons on our shirts and plastic handles of cooking pots and knives. Plastics have advantages and disadvantages.
|S/N||ADVANTAGES OF PLASTICS||DISADVANTAGES OF PLASTICS|
|1.||They are lightweight.||Some plastics produce poisonous flame when burnt.|
|2.||They can be moulded into different shapes and sizes.||They litter the surroundings.|
|3.||They are relatively inexpensive to produce.|
Rubber is a non-metal product. It looks like plastic but it is more elastic than plastic. It can be stretched easily. It returns to its original length when it is released after being stretched. Rubber does not allow water to pass through it. It floats on water.
Types of rubber
There are two types of rubber. Rubber can be natural or synthetic.
Natural rubber comes from milky liquid called latex which is extracted from the rubber tree.
Synthetic rubber is produced from organic materials derived from petroleum.
For more notes; see: https://passnownow.com/classwork-support/