Secondary 2 – Biology: Respiratory System
All living things have their own characteristics to stay alive, and so do humans. One of the characteristics that human has is breathing. Breathing is vital since we need to inhale oxygen and exhale the waste as carbon dioxide. Oxygen is needed to give us energy to do all the activities. Carbon dioxide as the waste needs to be expelled from the body through this system. In this topic, secondary 2 students did a simple experiment to prove that humans exhale carbon dioxide. They needed limewater, straw, and plastic cups. They had to blow the limewater by using the straw until the water was turbid. They did it and felt amazed by the result. ***
