DAILY QUESTION February 11, 2009 What is specific heat?

Agenda 2/11/09 Daily Question Ch 13 Section 2 Notes Assignments: http://www.wisc-online.com/objects/index_tj.asp?objID=SCE304 Assignments: 1. No assignment for tonight

3 Ways of Heat Energy Transfer Conduction Convection Radiation A campfire is the perfect example!  Figure 6

Conduction Takes place when two objects that are in contact are at unequal temperatures

Convection The movement of matter due to differences in density that are caused by temperature variations Only possible if the substance is a fluid A liquid or gas

Convection Currents The cycle of a heated fluid that rises and then cools and falls

Radiation Energy that is transferred as electromagnetic waves Differs from conduction and convection It does NOT involve the movement of matter

Conductors Any material through which energy can be easily transferred as heat Good conductors: metals Insulators Any material that reduces the amount of energy that can be transferred Poor conductors: wood, rubber

Specific Heat Describes how much energy is required to raise an object’s temperature A characteristic physical property Represented by c Table 1 shows specific heats

Specific Heat Equation Energy = specific heat x mass x temp. change Energy =cm∆t

Practice Problem How much energy must be transferred as heat to the 420 kg of water in a bathtub in order to raise the water’s temperature from 25°C to 37°C?