Laboratory classes are compulsory for chemistry students at every university in the world. The question is, why? They are a bit expensive. This is because of [inaudible] instruments, campus storage, and waste management. They are also time consuming and finally, significant health and certifications. So what is the reason for having them? At this stage, I usually hear an answer, because chemistry is an experimental science. I accept that, but what does it mean in educational context? Those students, do they remember more or do they understand more because they upset process statically. For example the transformation from the initial to the final substances in chemical reactions. From the other hand, the standard statement provided in laboratory manual is often the purpose of this laboratory classes is to confirm theory taught in lectures. So let's see, in that case demonstration by a teacher or lecturer which is usually much cheaper will also allow us to reach that goal. You may think, we mustn't forgot development of practical skills. Yes, you are right. It is of course only possible using practical classes. But isn't that all? Tell me, what is the purpose of your laboratory cause of courses? Let's start our role. When you have completed this module, you will be able to explain why we should have laboratory classes, describe different types of laboratory session with a focus on their purposes and finally, you will provide strategies on how to increase student engagement during demonstrations and hands-on practical sessions.