 You might have played the game of hide-and-seek right think of some places where you would like to hide so that you are not seen by others Why did you choose those places? Would you have tried to hide behind a glass window? Obviously not right as your friends can see through that and spot you Can you see through all the materials? What about what about this piece of paper? Can you see what's behind this paper? Those substances or materials through which things can be seen are called transparent glass, water, air and some plastics are examples of transparent materials For example, you can easily see the burning candle behind this glass and also through the water These are called transparent substances Shopkeepers usually prefer to keep biscuits, sweets and other eatables in transparent containers of glass or plastic So that you can come and pick up your favorite candy. On the other hand, there are some materials through which you're not able to see For example this piece of paper. Now if I place this paper just like this, I'm sure you're not able to see the burning candle Yes, you can see some light, but you cannot see that candle and of course you cannot see the glass that is behind it You cannot tell what is kept inside a closed wooden box, a cardboard carton or a metal container, right? Wood, cardboard and metals are all examples of opaque materials and even even this piece of paper So this is another way of grouping substances whether they are opaque or transparent. Now, let's see something interesting So what I'll do is I will take this piece of paper and I will put I will rub some oil on top of it Okay, so here I have the original paper. We cannot see the candle, right? But now after rubbing some oil on it, see what happens Do you find that the candle is more clearly visible than before? But can you see clearly through the oiled paper? No, right? Not entirely Not everything on the other side is visible So these materials through which objects can be seen but not clearly are known as translucent materials Here is one more example of a translucent material. This glass sheet when I place it in front of the candle You can't entirely see the candle, but you know, there is something on the other side something glowing something burning This also shows that not all glasses are transparent. Some can also be translucent So this is one more way to group a substance You can group a substance either as opaque through which you cannot see anything You cannot see on the other side of an opaque object a transparent object Through which you can clearly see what is on the other side and finally a translucent object through which you can see What is on the other side but not clearly