Detecting changes in the environment is a vital function of all living things for survival. This helps living things escape from danger as well as look for food and mates. Living things perceives environmental stimuli through various sense organs. The information collected by the sense organs will be sent to the brain. As a central coordinator, the brain integrates and interprets all sensory signals to give a comprehensive perception of the environment so that appropriate responses can be made.

In this Unit, students will learn about how sight and hearing are produced and the structures of corresponding sense organs. They will then learn about other senses and the role of the brain in detecting the environment. Students will also study the effects of alcohols, solvents and drugs on our judgements and responses, enabling them to make informed decision and refuse to take these substances.

Through performing practical works, e.g. dissecting an ox eye and finding out the reaction time of different persons, students will practise some science process skills like observing and conducting practicals. The study of topics on eyes and ears will also help them realise the unifying concepts “form and function”.