Right, so this is an image taken with an infrared telescope. So we're actually looking at infrared waves, made possible using computer processing. This galaxy, the angometer galaxy, is very, very large galaxy. It's over three times the number of stars contained within the Milky Way galaxy and just over twice the diameter of our own Milky Way galaxy. This galaxy is in fact on a collision course with our own and scheduled to arrive in about four billion years. Another photograph processed to make visible the invisible, that is the infrared rays, this is the Orion region of the sky. Now what you need to know about radiation is that different surface types will reflect or absorb it in different amounts. So silver surfaces, shiny, smooth metallic type surfaces are very good at reflecting this heat radiation, this infrared radiation. So for example when the sun shines on an object that has a silver surface, most of that reflected, most of the energy is reflected rather than being absorbed. Now on the other hand, there are other objects that are better at emitting this infrared radiation and what we find is that in fact darker objects, painted black or with rougher surfaces as well as being dull or black in color, are in fact better at emitting this radiation than say a silver object. So this means that source pans and metal kittles will usually have a shiny outside surface to reduce heat loss by radiation, keeping the heat inside the source pan or kittles as the idea. Central heating radiators are usually painted white, but in fact they will be radiating a lot better if they were painted black. So this idea of emitting or radiating the energy away from the surface, it's better with the darker and dull surface types. Alright, so here's a takeaway coffee or chocolate cup perhaps. The question is how is the cup designed to keep the beverage hot? And of course if you look at the three methods of heat transfer, you can answer this question starting with conduction. The material is clearly not a good conductor and so it will not pass heat through its surface, through the material, into the bench or the air. The second thing is to prevent convection, there's a lid on top. So heat loss by convection is slowed down by having that lid there. That prevents evaporation and any convection that does occur, traps the heat at the top of the cup. Lastly, the color, it's white, shiny, white surface, which means it will reflect heat back into the inside rather than let it absorb and then radiate out. So it won't do that, it will actually reflect the infrared rays back into the coffee keeping it hot. So just by looking at those three methods of heat transfer, conduction, convection, radiation, you should be able to answer such a question or similar type of questions. So in general terms, packaging for any takeaway, foods or drinks, obviously there's those are the three things I just talked about, the poor conductor, probably polystyrene in this case. The plastic lid prevents convection and evaporation. And the polystyrene being white would not be a good civil radiator. So essentially keep the heat inside the coffee quite effectively because of those three heat transfer reduction mechanisms.