A Catalyst article describing how a medical drug is made into a form which works well in the body. Medicines rarely contain just one pure chemical substance. The vast majority are made of a complex mixture that contains an active ingredient (the compound that has the desired effect in the body) and compounds called...

This Catalyst article looks at soil composition and the reasons behind protecting soil from turning into dust. The UN Year of Soils highlighted the many ways in which humans rely on soil for much more than growing crops.

This article is from Catalyst: Secondary...

A Catalyst article about how the study of ancient rocks and sediments can help deduce how the Earth's atmosphere has changed over billions of years. There used to be much less oxygen than there is today. This article describes how the composition of the atmosphere has changed through history; it also explains the...

This Catalyst article looks at how the structure and properties of chocolate change when it is melted and re-solidified. An experiment is described in which the differences between solid chocolate, and chocolate which has been melted and re-hardened can be found, along with a detailed explanation of the physics...

A Catalyst article about careers in educational psychology. For students of psychology there are a range of career options; this article looks at the role of an educational psychologist and a typical working day.

This article is from Catalyst: GCSE Science Review 2006, Volume 16, Issue 4.

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A Catalyst article looking at climate change. In particular the science of phenology, the study of the times each year that certain life-cycle events occur, is examined. It involves recording data on when birds migrate, eggs hatch or when leaves change colour. If the climate is changing, the timing of these events...

A Catalyst article about what causes faults in electrical appliances and the wiring installations in homes, and why people receive electric shocks. How regulations can reduce the risk of electrical faults and electric shocks is also examined together with the use of fuses, fuse wire and modern RCDs (residual...

A Catalyst article about the UK's extremely reliable electricity supply system generated in power stations which burn gas or coal, or use nuclear fuel. The article looks at how this is achieved using high voltages and how the demands for power at different times of the day and year are met.

This article is...

This Catalyst article looks at harlequin ladybirds, just one of the invasive species that has spread through Western Europe. Over the last century there has been a dramatic increase in the movement of so called alien species around the world as a consequence of international trade and travel. Invasive alien species...

A Catalyst article about the efficient use of heating systems. Many people complain of being too hot or cold. Coming soon are a new generation of intelligent heating controls which can learn how people live, and then deliver heating efficiently when and where they need it. These devices are known as Wattboxes and...

A Catalyst article devoted to food chains. This article looks at photosynthesis and the loss of energy from plants to animals throughout the food chain. How this limits the number of animals that can survive on the energy fixed by a patch of vegetation is explained. Foraging characteristics and how many animals can...

A Catalyst article about how the society can decide whether energy-efficient lighting is good for the environment. With the UK Government announcement that sales of filament lamps will be phased out over the next few years the article examines their replacements, CFLs, compact fluorescent lamps. Not everyone agrees...

A Catalyst article explaining how enzymes allow chemical reactions in all living organisms to proceed quickly, under conditions where they would normally be very slow. By isolating enzymes that could be used to catalyze reactions, scientists have started a major biotechnology industry. The article describes how...

Since the discovery of antibiotics, many people believe that the pathogenic microorganism threat to the population has been removed, with fatal infections and infectious diseases brought under control. This has discouraged research into drugs containing natural compounds such as essential oils. However, humans are...