Students will be demonstrated with the effect of the change in index refraction by inserting a laboratory tube in a bowl of oil. Students notice that the tube visually disappears. They are asked to work in teams and explore and find why this happens, and through a short presentation to present the phenomenon as they have understood it through collecting information online. Afterwards, the teacher explains the index of refraction, why it changes depending on the material or medium, the visual effect, etc. Finally, students are asked to replicate the experiment using water instead of oil, observe the phenomenon, comment on the degrees of refraction, etc.