 Have a candle in front of you like this. And now bring your hand closer to it. You will feel some warmth, right? You will feel some heat. Why does that happen? When you sit around fire, you can still feel the warmth from the fire, right? How is this happening? How is the heat getting transferred? Is this heat transferred due to conduction or convection? Let's think about it. Air is a poor conductor of heat, right? So the transfer of heat to your hand from the candle, it can't really take place through conduction because air is a very poor conductor of heat. And the hot air around the candle flame, it's lighter, right? So it will tend to rise. So the transfer of heat cannot also take place by convection because even if you are sitting near next to the fire, then also you are feeling the warmth. So it turns out that the transfer of heat in this case is happening by a method called radiation. Any hot object can radiate heat and it can radiate in all the directions. Let's have a look at this flower. Imagine that the center yellow part is like a hot object and the heat just like the petals, it's going in all the directions. Similarly, a hot object also radiates heat in all the directions. And the great thing about radiation is that even if there is no medium present, even if there is no air, still heat can be transferred by radiation. Just imagine how does the heat energy of the sun reaches the earth. The vast majority of space between the sun and the earth is a vacuum. There is no air present over there. But still the thermal energy, the heat energy, the heat of the sun reaches the earth even through this vacuum. And it reaches the earth by the method of heat transfer which is called radiation.