Explain how heat transfer is occurring through convection, radiation and conduction in this picture.

Heat is type of energy can be transferred in three different ways:

1) direction contact through collisions (also called conduction).  

Thermal conductuction is the transfer of heat through physical contact.

Thermal conduction is the transfer of heat by microscopic collisions of particles.

Heat spontaneously flows from a hotter (in this example hot liquid) to a colder body (in this example spoon).

2) through a fluid making a current created by less dense fluids floating and more dense fluids sinking (also called convection).  

Stirring hot liquid with spoon.

3) by waves traveling with or without a medium (also called radiation).

Waves radiate from hot liquid.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

hurricanes form in warm water