Water and more
Water is a LIQUID but it can also be a SOLID and a Vapor (or GAS) …
These are called PHASES
Iced water is in the liquid phase with the solid phase, the ice, floating on top.
A frozen lake is a layer of the solid phase of water on top of the liquid phase.
Let’s move on from the word “phase” out of it for now…
When you cook vegetables in some water, there is liquid water and water vapor also called… STEAM.
Let’s talk STEAM…
When you add enough HEAT ENERGY to water, let’s say on the kitchen stove, it will start to BOIL at 100 degrees Celsius, when the pressure of the air is one ATMOSPHERE. This is the case when we are at sea level, or about.
At lower pressures, say on top of the Himalayas water boils at a much lower temperature.
At higher pressure than one atmosphere, water boils at higher than 100 degrees Celsius.
That’s why mountain climbers take little PRESSURE COOKERS up the mountain …
To cook their food.
PRESSURE COOKER ?
A pressure cooker is like a boiler; its top is a strong lid that locks in place. It has a pressure valve, just a weight, and a safety valve. It is used for cooking food by STEAMING it.
Let’s do some experiments with STEAM… in the next unit.