explain how water can transfer energy by conduction and by convection.
http://en.wikipedia.org/wiki/Convection
http://www.mansfieldct.org/schools/MMS/staff/hand/convcondrad.htm
Water can transfer energy through both conduction and convection.
Conduction is the process of heat transfer through direct contact between particles. In the case of water, it occurs when molecules with higher kinetic energy collide with neighboring molecules with lower kinetic energy, transferring energy between them. In other words, the energy is passed from one molecule to another through molecular collisions.
To understand how water transfers energy through conduction, consider a pan of boiling water on a stove. As heat is applied to the bottom of the pan, the molecules in direct contact with the hot surface gain energy. These molecules then collide with nearby cooler molecules, transferring some of their energy. This process continues, creating a chain reaction in which heat is gradually conducted through the water mass.
On the other hand, convection is the process of heat transfer through the movement of a fluid (in this case, water) due to differences in density caused by temperature variations. Convection occurs because warmer water is less dense and tends to rise while cooler water sinks, creating a circulation pattern.
To understand how water transfers energy through convection, consider a pot of boiling water. As heat is applied to the bottom of the pot, the water closest to the heat source becomes warmer and less dense. This warm water rises to the top while the cooler, denser water sinks to the bottom. This creates a flow or current within the water known as a convection current. As the hot water rises and the cold water sinks, energy is transferred throughout the entire pot of water.
In summary, water transfers energy by conduction through direct molecular collisions, and by convection through the movement of warmer and cooler water. Both these processes play important roles in how water heats up or cools down in various situations.