In the U.S., gas is the short form of gasoline, while in many Commonwealth countries, it is known as petrol. Gas is a petroleum-derived liquid mixture that consists of hydrocarbons and is used as a fuel in internal combustion engines.

There are different types of gasoline in the fuel industry. Small aircrafts use specially formulated, high-octane aviation gasoline, which cannot be used for ground vehicles. Vehicles involved in racing use specially formulated racing gasoline that has very low levels of benzene and an anti-knock index of at least 100. Gasoline used for scientific research has unusual properties, which depend on the nature of the research. Cars with gasoline engines use E85 gasoline that is a blend of 85% fuel ethanol and 15% gasoline. The reason gasoline is added here is to provide a good start and warm up performance to the car, which is possible because of ethanol's low volatility.

The diesel engine cars or cars with compression ignition engines use E95 gasoline that is a blend of 95% fuel ethanol and 5% gasoline. No more than 5% gasoline should be added because this may lower the flash point to unacceptable levels. E85 cannot be used in diesel applications, and neither can E95 be used in gasoline engines because of the different types of engines.

It is always better to buy gas during the coolest times of the day, like early morning or late evening as this is when gas is found at its densest. Gas pumps measure according to volume of gasoline and not density of fuel concentration, so you have an advantage here. It is better not to fill your gas tank to the top as overfilling results in the sloshing over of the gasoline out of the tank. Gas has to be chosen wisely for use in vehicles because some brands have greater economy due to its better quality. It is always better to use brands that seem to be beneficial. To save gas, it is better to avoid too much warming up of the engine, even on cold mornings. About thirty or forty-five seconds of warming up is more than enough. Avoid unnecessary starting and stopping of the engine. You use the same amount of gas here as you would in idling the engine for one minute. Use gas wisely, as it is an unrenewable fuel source that will always be needed by mankind.