what the atmosphere is and how the sun heats the Earth what causes variations in weather how we gather information about weather how to interpret data on weather maps how weather events form and how they impact on us.
ICE-BREAKER ACT VITY
Watch the weather forecast for Ireland. Make a list of the elements of weather (e.g. temperature) that are mentioned. In groups, discuss how each of these aspects is measured.
The atmosphere Learning Intentions
In this section, you will learn: zz what the atmosphere is made up of.
The atmosphere is a thin layer of gases that surrounds the Earth. Seventy-eight per cent of the atmosphere is nitrogen, 21 per cent is oxygen and less than one per cent is made up of other gases (including argon and carbon dioxide).
The atmosphere insulates the Earth from extreme temperatures. It traps heat and it also protects the Earth from dangerous rays from the sun.
Layers within the atmosphere
The Earth’s atmosphere is about 480 km thick, but most of it is within 16 km of the Earth’s surface. There is no exact place where the atmosphere ends. It just gets thinner and thinner, until it merges with outer space.
There are several layers within the atmosphere. The troposphere is the lowest layer in the Earth’s atmosphere.
• It reaches from ground or water level up to about 17 km. • Weather and clouds occur in the troposphere. • The temperature generally decreases as the altitude increases.
