Week 2.pdf

Assist Prof Sevim ŞAHİN Measurements in Physics Assist. Prof. Sevim ŞAHİN What is physics then? The branch of science concerned with the nature and properties of matter and energy. The subject matter of physics includes mechanics, heat, light and other radiation, sound, electricity, magnetism,...

Assist Prof Sevim ŞAHİN Measurements in Physics Assist. Prof. Sevim ŞAHİN What is physics then? The branch of science concerned with the nature and properties of matter and energy. The subject matter of physics includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms. +273 C = (5/9) x (F-32) Unit of Mass Units of Lenght Units of Volume Heat and Temperature Definition of Heat and Temperature Heat is a measure of the internal energy of the molecules that make up a substance. Heat may be transferred from one substance to another. We say that substances can absorb or radiate heat. Temperature is a measure of the average kinetic energy of the molecules in a substance. Energy, heat, and temperature are all related. Thermodynamic Equilibrium and Temperature The quantities which describes a system as a body are called state variables. (Durum değişkenleri) ⚫ T, temperature ⚫ P, pressure ⚫ V, Volume, ⚫ M, mass. No matter how complex the internal structure of a macroscopic system, with a limited number of the state variable, the system can be defined as a whole/ body. If a system's state variables do not change over time and if it is the same value everywhere, this situation is called thermodynamic equilibrium. The Zeroth Law of Thermodynamics If the two separate objects are in thermal equilibrium with a third object, then their heat with each other is in balance. Temperature Temperature, which is the most fundamental thermodynamic quantity, is the quantitative measurement balance of thermodynamic equilibrium. Temperature When the two bodies with different temperatures such as A and B contact each other but isolating, eventually their temperatures will be equal. It is called as thermodynamic equilibrium. Here we describe the temperature, macroscopicly. However, the temperature is a measure of the average kinetic energy of molecules which form a system. (Microscopicly) When the temperature of an object changes, another quantity must be changed. For example, a heated piece of iron expands, a heated gas pressure increases or the electrical resistance of a heated wire increases. The temperature measure is defined over the properties. An instrument that measures temperature is called a thermometer. The most popular thermometer type is the mercury thermometer. Liquid mercury expands with temperature and rises. However, mercury is a poisonous substance, it is now replaced by dyed alcohol.