PHY 317K 1st Edition Lecture 20 Outline of Last Lecture I. Problems over the Exam DiscussionOutline of Current Lecture I. Explain why different substances have different specific heat capacitiesII. Solve problems involving specific heat capacitiesIII. Describe the solid, liquid, and gaseous statesCurrent LectureExplain why different substances have different specific heat capacities.- Heat two same size objects of different materials for the same amount of time they will not necessarily have the same temperature. - Some material’s temperature increases (and decreases) more quickly or in other words with less heat energy added (or removed). - Objects of the same size or same mass have different numbers of molecules or particles and those molecules/particles have different masses. - There are many factors that influence how much heat it takes to change the temperature of a material…- Heat capacity of a body is the ratio of heat supplied to the corresponding rise in temperature of the body:- Where Q is the heat and is the change in temperature. - The heat capacity of an object is useful but does not tell us much about the material the object is made of, 4 kg of water will have a larger heat capacity than 1 kg of water. - Specific heat capacity is the heat capacity per unit mass. - This gives us information about particular materials not just an individual object.Solve problems involving specific heat capacities- Energy is conserved. The energy put into heating an object must be equal to the energy coming out of the object as it cools. So who cares? This provides a simple way of measuring the specific heat capacity of a material…- A calorimeter is used to measure the specific heat capacity of materials. - It usually consists of a thin metal canister that is thermally insulated from the environment. - The calorimeter is filled with a know mass of water and the temperature of the water is recorded. - The material whose specific heat capacity is to be measured is heated and its temperature is taken.- The material is then placed in the water and the water is stirred. - After the water comes to thermal equilibrium the temperature of the water is recorded.- Knowing the specific heat capacity of water, the mass of the water and the temperature change of the water we can calculate the heat energy transferred to the water from the heated material. - From that we can calculate backwards to find the specific heat capacity of the material inquestion.- Where the subscripts x and w stand for material x and water respectively. - For accurate measurements the heat absorbed by the water and by the thermometer needs to be taken into account.- Of course you may notice that this method only work if the specific heat capacity of water is known. - To measure the specific heat of water (or other liquid) you must have an accurate way ofmeasuring the heat energy added to the water. - You must also have a way to ensure that all or a known amount of the energy goes into heating of the water. - With the use of a modern (electric) joulemeter this is done with relative ease.Describe the solid, liquid and gaseous states in terms of molecular structure and motion- In a solid the particles are held tightly in a lattice. - There is very small space between individual particles. - The particles have vibrational kinetic energy. - Particles in solid have lower energy than in liquid or gas form. - Most solids are considered incompressible, meaning you push on it and the volume doesn’t change.- In a liquid the particles are still packed closely together but they are free to move relative to one another, thus liquids can flow. - The particles have vibrational, rotational and translational kinetic energy. - Particles in solids have lower energy than in a gas. - Liquids are virtually incompressible; this is why they can be used in hydraulic systems.- In a gas the particles are very spread out. - The particles have vibrational, rotational and translational kinetic energy. - Gases are highly compressible; the volume of a gas is largely dependent on its temperature and the pressure of the