The newly revised specifications for GCSE science involve greater consideration of climate change. This topic appears in either the chemistry or biology section, depending on the examination board, and is a good example of "How Science Works." It is therefore timely that students are given an opportunity to conduct some simple climate modelling. The demonstrated model will allow a range of student abilities to investigate the major factors that affect the climate. The model itself has been condensed into a straightforward spreadsheet as well as a web version of the model, and represents a "One Layer Atmosphere Model of the Earth." (Contains 3 figures and 1 table.)