Heat travels from hot to cold until an equlirium is established (when everything is at the same temperature). Heat can travel in 3 different ways, called conduction, convection and radiation.

 

Radiation- Heat is transferred by electromagnetic waves like infrared (IR) and light. 

Even objects that look cold to us emit IR. An ice cube for example, emits IR. Read more here: 

A metal at room temperature emits IR, but if it is heated in a fire much more IR is emitted. If it gets very very hot, it starts to emit light as well, initially red light. This point is called red hot. I say initially because red is the colour with the least energy. Blue and violet are at the higher end, and the full order can be observed in a rainbow. 

For example, the hottest stars are blue, the colder ones (relatively) are red and yellow. We cannot perceive star colour because very little light reaches our eyes. Is the same thing that happens when you are in the near dark and can't see colours, only black and white. That is to do with the 2 different types of cells that we have in our retinas, to convert light to electric (neural)  impulses. In a big telescope more light can be collected and colours can be seen (link Hubble Space Telescope).:  

Conduction – Heat is transferred by contact, or touching. This can be understood with the particle model: particles that move faster in one material (the hotter one) hit particles on the other material making them move faster . 

 

Convection – Heat is transferred by moving particles in gases and liquids. The heated liquid (or gas) has its density reduced, as a result of the increase in distance between its particles as a result of higher speeds, so that it moves up. Next, it cools down because of its increased distance from the source of heat, and comes back down to be heated again. And the cycle starts again... 

Typical examples of convection are the heat radiator (for air) and pan (for water).

The heat radiator, present in many households, heats the air so that it moves up (so that cooler air occupies its place), cools down and then moves down. These movements help to spread the heat around a room.

In a pan over a stove the water is heated at the basis due to conduction from the metal to the water. It moves up and colder water takes its place to get heated and moved up as well. This way, the heat spreads quicky to the whole volume of water.