Homework

Where does water come from?

Water on Earth cycles from the oceans, where it evaporates from the surface, into the atmosphere, forms clouds, falls onto the land as rain, travels through wet lands, rivers, lakes and underground, then returns to the ocean — collectively known as the hydrologic cycle.

Why do cold water bottles and soft-drink bottles sweat?

The air surrounding the bottle gets cooled by the cold drink. When the air outside is cooled, it cannot hold more moisture. So some moisture condenses and becomes water. This water stays outside of the bottle and makes us think that the bottle sweats.

When does water boil?

The boiling point of water is typically considered to be 100 °C or 212 °F. Pressure and the change in the composition of the liquid may alter the boiling point of the liquid. High elevation cooking generally takes longer as boiling point is a function of atmospheric pressure.

Why is water blue?

The ocean is blue because water absorbs colours in the red part of the light spectrum. Like a filter, this leaves behind colours in the blue part of the light spectrum for us to see.

When is water the most dense?

As water cools, it becomes more dense. At 39°F (or 3.98°C to be exact) water is the most dense. This is because the molecules are the closest at this temperature.