Simple Machine

EFFICIENCY

We stated that some of the energy produced by a machine is not available for doing useful work; some of the energy is used to produce heat. This means that not all the energy put into a machine is available for doing useful work.

INCLINED PLANES

Have you seen people moving barrels or oil drums from the ground on to a lorry? They don’t lift them but they push them up a sloping board which we call a ramp.

Sometimes it is the tail board of the lorry that is used for this purpose. It is easier to push a heavy load up a slope to a certain height than it is to lift it up to that height.
Have a look at stairways in tall buildings. They are not steep but they slope gradually. Would it be easier for you to climb a ladder to get to the top of a tall building, or walk up the longer, but less steep, stairs?

SCREWS AND WEDGES
You must have seen a carpenter use a wedge to tighten a joint, and a tailor use a needle to sew a piece of cloth.
Have you used a wedge to split wood? Have you used an axe to chop firewood? All these tools are machines.

They enable you to do something you could not do with your own unaided strength. And they are all types of inclined plane. A screw is a machine too. It is easier to drive a screw into a hard piece of wood than it is to push a drawing pin into it.

MAINTENANCE OF MACHINES

You must have seen a car being serviced in an auto-mechanics workshop, or an air conditioner being serviced. This keeps service machines in good repair and it is necessary for it to be done regularly. When machines are in use, their moving parts do work, and so energy is involved. Some of this energy produced by the machine is not available for doing useful work. Some is used to produce heat as the friction between the moving parts is being overcome.

In order to reduce the heat produced as the machine works, the friction between its moving parts must be reduced. One way of doing this is to grease the moving parts. But as the machine works, the grease is soon used up and unless this is replenished, more and more heat will be produced until the machine breaks down. To avoid reaching this breakdown stage, it is necessary to grease the moving parts regularly. The use of oil and ball bearings are other ways of reducing friction between moving parts.

Dirt in parts of a machine will restrict movement and cause wear. Regular removal of dirt from a machine is thus very necessary to ensure the good performance of the machine. In a car engine, oil reduces the friction between the moving parts of the engine to ensure their smooth movement and so obtain good performance from the engine. As the oil moves round these parts, dirt is collected and after some time, the oil becomes dirty. The oil must be changed to keep the engine going smoothly; otherwise the engine will be damaged. If, on the other hand, the engine has no oil at all, the parts inside soon heat up and get damaged during use. Regular checking and changing of the engine oil is an important practice and changing of the engine oil is an important practice recommended for all users of motor vehicles.

Have you seen the carburettor of a motor vehicle?
It is the compartment where air is mixed with petrol in a petrol engine. If the carburettor is dirty, the jet for the petrol becomes blocked. When petrol cannot pass into the space where air can mix with it, the engine will not work and so the vehicle will not move. Each time a vehicle is serviced, it is very important that the carburettor is cleaned properly and placed back in the correct position.

Even when an engine is not in use, it is still necessary to check the parts occasionally and warm it up; otherwise it becomes rusted and damaged. In Nigeria, some of the greatest problems we have with machines are the effects of dust and rust. Our best remedy is regular maintenance in the form of cleaning and general servicing.
What has been said above applies to all machines including the tools we use in our homes. For these to have a long life, they must be regularly maintained. All machines should be checked regularly for any faults. If any are detected, they should immediately be corrected, no matter how minor they may appear to be.

Note!
Visit an auto-mechanics workshop and identify where and how the engine oil is changed, and where ordinary water, brake fluid and distilled water, are applied.

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