The Atmosphere

A Year Ten module from the Salters’ double award science course. The first section of the module introduces the formation, composition and structure of the atmosphere. The Sun is our main source of energy. Students consider why sunlight is more intense near the equator and how the tilt of the Earth’s axis causes the seasons. Measurements of heating and cooling water and soil show how temperatures are moderated in coastal regions. Surface temperatures of different planets are compared and linked to the effects of their atmospheres. The spectrum of sunlight is compared to that of radiation emitted from the Earth and the absorption of radiation by gases in the atmosphere to cause a ‘greenhouse’ effect. The pressure exerted by the air is explained using ideas about moving particles. The design and function of barometers is discussed. Experiments on the expansion of gases when heated introduce the absolute temperature scale.

Ideas about pressure are extended to study of liquids. A simple hydraulic system is made and tested, and students consider how car braking systems work. Ideas about force, area and pressure, and about force, distance moved and work done can be revised.

Section 1: Has Earth always had an atmosphere?
Students’ existing ideas about the atmosphere are discussed. Experiments provide a rough measure of the oxygen content of air and show the presence of carbon dioxide and water vapour. Theories of he formation of the Earth lead to a data interpretation exercise on the evolution of the atmosphere, using evidence from the fossil record and rock compositions. The layered structure of the atmosphere is described.

Section 2: Here comes the Sun
Students consider why sunlight is more intense near the equator and how the tilt of the Earth’s axis causes the seasons. Measurements of heating and cooling water and soil show how temperatures are moderated in coastal regions. Surface temperatures of different planets are compared and linked to the effects of their atmospheres. The spectrum of sunlight is compared to that of radiation emitted from the Earth and the absorption of radiation by gases in the atmosphere to cause a ‘greenhouse’ effect.

Section 3: Gases under pressure
Experiments illustrate the pressure exerted by the air and this is explained using ideas about moving particles. The design and function of barometers is discussed. Experiments on the expansion of gases when heated introduce the absolute temperature scale.

Section 4: Pressure in liquids
A simple hydraulic system is made and tested, and students consider how car braking systems work. Ideas about force, area and pressure, and about force, distance moved and work done can be revised.