Using everyday examples to teach about oxidation-reduction reactions.
Occurring side-by-side, reduction and oxidation reactions involve the transfer of electrons between two species. These reactions are all around us: storing and releasing energy in our bodies, fuelling combustion, and powering our smartphones. They are also to blame for the spoiling of food and the rusting metal on your bicycle, and are linked to effects of ageing and conditions such as cancer.
Redox reactions have important roles in a wide range of biochemical processes. Knowing how these reactions take place in living cells is important for understanding cellular mechanisms such as ageing, inflammation and cancer. To study this scientists are using fluorescent biosensors to monitor where redox species travel in cells and how they influence or maintain the redox state, both in healthy individuals and in cancer patients.
One major biochemical process involving redox reactions is metabolism and the production of energy. Much like our bodies, our homes get energy from redox reactions too. Most of our energy is currently produced using fossil fuels but, an alternative, low carbon option is using hydrogen. When burned directly or oxidised in fuel cells, the only by-product is water. You can introduce the idea of the ‘hydrogen economy’ in your classroom and build a low-cost hydrogen fuel cell to explore how these devices produce electricity from hydrogen. The activity can be used to introduce the applications of redox reactions and highlights that chemistry can play an important role in protecting the environment. For another practical activity take a look at this Science in School article which shows how a microbial fuel cell generates an electrical current by diverting electrons from the electron transport chain of yeast.
Another power source your students might be most interested in is the one inside their smartphones. Batteries allow us to use mobiles and other devices without the need to be constantly plugged into a power socket and the role of oxidation and reduction reactions in powering our devices is described nicely in the TedEd video below.
Lithium-ion batteries are one common type of rechargeable battery but, despite their advantages, they are not perfect. Their low capacity and durability are factors that have delayed implementation, for example in electric vehicles. Scientists at the Institut Laue-Langevin (ILL), however, are working to improve the characteristics of these batteries. Find out how they made a supersized battery so they could see what was happening inside while the battery was running.
Although these links provide you with some novel activities to inspire your class about redox reactions, there are particular topics that some students find tough. Our final resource from the UK’s Royal Society of Chemistry however, will allow you to familiarise yourself with the common difficulties, and find out about some of the strategies you can use to deal with them.