1. Well, to begin the combustion reaction of burning organic material is exergonic. Basically meaning it releases energy. In the case of a campfire, it would be heat energy. This energy is stored in the wood by the process of the wonderful photosynthesis and the heat energy causes the air around the campfire to gain that energy into its system. You feel the heat energy because the difference between your body temperature and the air around you is decreased due to the heat from the fire, meaning you are losing less heat in the outside environment. That would be classified as a radiation heat transfer.
2. Depending on what oven you use. There are two type, gas and electric. However, what is common about these two is that they emit thermal radiation, either baking (heated below the food) or broiling (heated about the food) the food. They take electricity and convert that into convection thermal radiation where a metal element gets heated up, causing the food to cook.
3. And last but not least, I believe what you are asking is why is the inside of an automobile hot after it has been left sitting in direct sunlight for several hours. There is a phenomenon known as the Greenhouse Effect. Basically the sunlight travels from the sun in the visible part of the spectrum. The sunlight is then absorbed by the surface of the car and the surface begins to absorb the sunlight's radiated energy and that is what makes the inside of the car hot.
1) heat flows from hot to cold. the heat from the fire is let off from the exothermic reaction of the fire and warms up the surroundings, including yourself.
2) food is cooked in the oven by heat transfer. the heat warms up the pan and thru conduction, the food is heated and cooked.
3) I'm guessing this question is y it heats up? the answer to that is that the heat waves from the sun is absorbed into the car from radiation and thru convection the whole car is heated
There are two primary factors: size and distance from the Sun. Gravity helps planets and moons to hold on to their atmospheres, so small planets/moons such as Mars and the Moon have thin atmospheres. The reason why the outer planets are larger is probably down to two major factors. The first is simply the amount of material available which may be accreted to a planet. Clearly, the further away from the Sun, the longer the orbit (twice as far means an orbit twice the physical length).
