Urgent Oil Question HELP !!!!!

[Zonda11]

I need to know why you would use a certain oil in a lawnmower while you would use another type of oil in a snowblower. It is on an exam i have on monday - as one of these Thinking outside the box type questions for chemistry.


I know it has to do with Temperature and oil thinkness - but i need a more in depth explanation.

HELP!!!

Thanks

[GT-R_R34]

Oil Viscosity

Engine oil must be able to function under any operating temperature. Whether the temperature is below freezing or over 200°F the oil must be able to flow freely, while providing lubrication. Viscosity is a term used to describe the internal friction of a fluid. An oil with a low viscosity will flow very freely and not stick to moving parts, while a high viscosity oil tends to flow more slowly, but will adhere to parts better.

Petroleum products tend to become thicker at low temperatures, and thin out as the temperature rises. The oil that is manufactures for vehicles goes through numerous processes to reduce the oils tendency o change viscosity as the temperature changes.

The Society of Automotive Engineers assigns numbers to oils of different viscosities. The lower the viscosity, the lower the assigned number will be. For instance, a SAE 5 oil has a lower viscosity than a SAE 30 oil. Normally oils with a low viscosity are used in cold weather and oils with a high viscosity are used in warm weather.

An important step in the development of engine oil was the creation of multi-viscosity oil. Multi-viscosity oils act in a different manner under different temperatures. An example of a multi-viscosity oil would be 5W-30. A 5W-30 oil acts like SAE 5 oil when it is 0°F and like an SAE 30 oil when tested at 210°F. These oils are extremely useful in areas that experience wide swings in temperature.

see if that works.

[Zonda11]

Thanks alot -- It was very important to know which oil is used in which conditions and why.