Igneous Rock is formed when a magma cools underground and crystallizes or when it erupts unto the surface of the ground, cools and crystallizes. Magma that erupts onto the surface is called lava. When magma cools slowly underground the crystals are large enough to see.
Readings for compression tests usually vary between 175 to 250 PSI (Pounds per Square Inch). A higher reading generally indicates better engine performance; however you should check your vehicle manual to find out what the ideal reading should be for your vehicle.
Engines with higher compression ratios are generally considered better because they create more power while still maintaining efficiency. Ad. To calculate the compression ratio of an engine, an engineer would first calculate the volume a cylinder in the engine can hold when the piston is at the bottom of the cylinder.During one stroke of the engine, the piston moves from the bottom up toward the top and compresses the air-fuel mixture.0 hilariously insightful foreign words. Compression ratio refers to the volume, or amount, of an air and fuel mixture that the combustion chamber in a combustion engine can hold when it is empty and at its largest size compared to the volume it holds when the mixture is compressed down to the smallest size possible.