 Alright guys, so are you teaching something? Yeah, I am discussing mechanical and non-mechanical things. Oh my God, that is a little high-five. So I am here to talk about something basic, more basic, which you might have experienced already. He is Subbu by the way. So he is 6 feet taller. So now the question is, have you ever... This is 9th class, 9th class. So have you ever observed that when you try to look through the paper, paper is opaque, but when paper is soaked with oil, does it become transparent? Translucent. Translucent is the word. Now, how does it have... What makes it translucent? Oil makes it translucent. When you dip the paper on the oil, it becomes translucent. Basically, I think... So she has a first logic. Tell me. I am not sure, but I think maybe when you moisten the paper, it gets cleaner than it already is. Alright. Then see through it. Alright, so this is the logic. Now going by this logic, if I soak the paper in water, will it become transparent? What do you think? No. It becomes translucent when you put it in water. Yes. Oil works better or not? Oil works better. Oil is lot better, lot better. Because it's less dense. So he has another logic. Tell me. No, no, no. I just... I think it's okay. Tell me. Maybe because the density... Oil is less dense than water, hence due to that, maybe that could have made it more transparent. Okay, so he is saying that because oil is less denser than the water, that's why it makes it transparent. It's close up to the logic but still very far, actually. Anybody else? Anybody else? Now, Ajay, tell me one thing. The paper which you have, does it have pores or it is like complete without pores? It has pores. It has pores. It has pores. So if you have to see an object, what should happen? Light from the object should come from the object and reach your eyes. Yes or no? Yes. So pores are there but earlier the light was not able to come through the pores to your eyes. The reason is... One is this small, other is... The pores, the oil inside the pores reflects the light. Okay. Not the oil, without oil. If oil is not there, the light is not able to reach. Have you heard about... Have you heard about the scattering of the light? Yeah. What it is? Scattering means what? Tindle effect. Tindle effect. I mean, how does it happen? Particles come in the path of light to which light gets scattered in various directions. Okay, what else? I mean, is he correct all of you at least? Particles are the same size as the light waves. Wave length. Wave length of light. So basically what happens, the pores are there but there are these pipers which absorb the light and then emit the light. That is scattering. And then it emits it, it emits in all directions. So you are not able to see through properly. But when you soak the oil, oil has similar refractive index as that of the paper. That is point number one. And second, when the light comes through the pores, now it has to cross the oil and it blocks that finer elements which could scatter the light. And hence scattering is stopped and the light is able to transmit through the pores much easily now. Have you understood? Yes. Thanks for participating.