There is a huge range of approaches to each topic, and no single one is right or wrong! Feel free to interpret each question as you wish, and thus explore areas of science YOU find particularly interesting - this passion will come across to the reader and make your essay stand out. You should also make sure you reference your essay correctly (make sure you use a wide range of sources, not just Wikipedia, and chose them selectively to ensure they are reliable and relevant), use a suitable structure (introduction, main points, conclusion), and include relevant examples and images where appropriate.
You cannot write your essay on a topic you have studied in detail at school, and there is a limit of 2 entrants per school per competition - however they do mention that they could be flexible on this so if you attend a large school and several students are interested in entering make sure you ask your teacher to contact them.
Not only would this be great to mention on your personal statement, you could win £500!
The deadline for entries to be received is the 14th March 2016.
For more information, visit their website and click on the link to the Kelvin Science Prize.