Earthâs crust is made of rock, and rock is made of natural substances called MINERALS. There are three main types of rockâsedimentary, igneous, and metamorphic rock. Each type is produced in different ways.The oldest rocks on Earth were formed about 3.8 billion years ago.arthâs crust is made of rock, and rock is made of natural substances called MINERALS. There are three main types of rockâsedimentary, igneous, and metamorphic rock. Each type is produced in different ways.
The first step to energy efficiency in your kitchen is to consider your appliances, and appliances with the ENERGY STARÂ® seal of approval are always the most energy efficient. Convection ovens also make a difference. The heated air is continuously circulated which reduces cook times as well as the temperatures required. On average you'll use 20% less energy a month running your convection oven, as compared to a standard oven.
This is what is known as a convection current. Itâs what happens when you heat a pot of water on the stove or turn on a convection heater in a cold room. Because air is a poor heat conductor, convection heaters work slowly, gradually warming the air until itâs reached a uniform temperature. Types of Convection Heaters There are five types of convection heaters: oil, ceramic, water, fan heaters, and furnaces. Each works on the same principle, but generates and distributes heat in different ways.