C1 Topic 1: The Earth’s Sea and Atmosphere This topic looks at: How the early atmosphere and oceans were formed How levels of carbon dioxide reduced and levels of oxygen increased The impact of volcanic and human activities on the atmosphere Carbon Dioxide in the Atmosphere The constant recycling of carbon is called the carbon cycle. Draw the carbon cycle: Global Warming The level of greenhouse gases in the atmosphere has gradually increased as a result of: 1. 2. 3. 4. Draw or write the timescale from the formation of Earth to how it is now: Draw or write the composition of the Atmosphere has changed from the formation of the Earth to now: Oxygen in the Atmosphere The levels of oxygen in the atmosphere have changed throughout the history of the Earth. Below briefly explain how: Keywords: Oceans, Water Vapour, Photosynthesis, Draw or write key factors and events that shaped the atmosphere Put the following in the correct order (Number them) The burning of fossil fuels also releases carbon dioxide into the air Plants and animals respire, releasing carbon dioxide into the atmosphere Carbon dioxide is removed from the atmosphere by green plants during photosynthesis Microorganisms feed on dead plants and animals, causing them to break down, decay and release carbon dioxide into the air. Keywords: Carbon dioxide, Nitrogen, Carbon Cycle, Global Warming, Fossil Fuels, deforestation.

P1b) Radiation & the Universe Structure of the atom Nuclear radiation deflected in magnetic and electric fields helium nucleus deflected in magnetic and electric fields electron Not deflected e.m. wave Thickness control half life years Beta radiation PROTON – positive, same mass as neutron (“1”) NEUTRON – neutral, same mass as proton (“1”) ELECTRON – negative, mass nearly nothing Half – life Time it takes for number of radioactive nuclei/count rate to fall to half its initial value Half lives Tracers half life hours Gamma radiation 100 200 Activity Time (s) 5 10 T 2T 3T 4T P1b) Radiation & the Universe Keywords: radiation, half-life, proton, neutron, electron, isotope, alpha, beta, gamma Isotopes Penetrating power In air : α- 5cm β- 1m γ - km Ionising power Alpha – very Gamma - weakly Smoke Alarms – half life years Alpha radiation Smoke detectors Keywords: ionising, penetration, range, tracer