* Burning gasoline in a car engine. When you start your car, the gasoline in the engine is mixed with air and ignited by a spark plug. This creates a combustion reaction that produces heat and energy, which drives the pistons and makes the car move.

* Burning natural gas in a stove. When you turn on your stove, the natural gas is mixed with air and ignited by a spark. This creates a combustion reaction that produces heat, which is used to cook food.

* Burning wood in a fireplace. When you light a fire in your fireplace, the wood is oxidized by the oxygen in the air. This creates a combustion reaction that produces heat and flames.

* Burning candles. When you light a candle, the wax is oxidized by the oxygen in the air. This creates a combustion reaction that produces heat and light.

* Digesting food. When you eat food, the carbohydrates, proteins, and fats in the food are broken down by enzymes in your digestive system. This process releases energy, which is used to power your body's activities.