Physics - General Physics (1) - Properties of Matter and Heat PDF

# Physics - Classical physics - M. (P. of matter and Heat.) - E.,M. - W.M.( S.,L.) - Who needs to study This branch? - Physicists (F. of science) - (The course of the first level students) - Engineers - Biology - Medicine - Agriculture...

# Physics - Classical physics - M. (P. of matter and Heat.) - E.,M. - W.M.( S.,L.) - Who needs to study This branch? - Physicists (F. of science) - (The course of the first level students) - Engineers - Biology - Medicine - Agriculture - Pharmacy - Modern Physics - Re... Q.M... - A. and N.P. ..... B.P. - 1- Temperature and Thermometry - 2- Theory of Ideal Gas - 3- Thermal Energy # General Physics (1) ## (Properties of matter and Heat) ### P 101 #### Heat # Nature Background from our experience: Fig.1-2 Childhood ## Boy ## Girl - Fig.1-2 - Hi. Thermal energy - Hi. Temperature - Lo. Thermal energy - Lo. Temperature - Advantages: - (For girls) She believe in the experience of the old people in her family such as: - Store food in cool place or Refrigerator. - Avoid the sun, hot stoves and...so on. - Control the Temperature inside the home or car and protect herself from wind chill and heat stroke. - Disadvantages:-(For boys) Avoid all the warning against heat: The sun, hot stoves,.........etc. - Believe in the principle that “The Experiments is the best “. # 1-1 Thermodynamic Science[4,4」 : - Introduction: Thermodynamics is a special study about the work of all equipment's, apparatus, devices and tools, which had made up or invented by human. For example, from the steam engine (in the ancient time) till the electric cars (nowadays). The scientist were very busy to put rules and laws to the works of theses all equipment's. - Def.: Is the study and the application of the thermal energy (heat and Temperature, and its affects)on systems. - System: Any thing life or not, which are controlled by a group of rules. - Concepts: - (1) Measurement of the change of the degree of temperature of the system, study its reaction with the internal energy of this system (Expansion. and Contraction.) and mechanical works(as a result). - (2)Study the relation between heat and the different kind of energy (Electricity, Radiation, Mechanical energy....etc.) through some rules which connect them in the form of Thermodynamics four lows. - Examples: (How many systems you know?). See the following Fig.1-1 # Question and answer: - Put right or wrong in front of the following pictures. - Which one of these pictures explains the symptoms of the heat stroke ?. # Chapter -1- ## Temperature and Thermometry ### Lecture -1- # Qusstions and answers: - Choose the correct answer from the following question: (2,1,1,2,2,1) - 1- A metal ice is colder than a package of frozen vegetables (in our hand) because there are: - a - Direct connection. - b - An insulator. - c- Indirect connection. - d-b and c together. - 2-A cup of hot coffee is cooled when we put a piece of ice in it because they are in : - a - Thermal contact - b - Thermal equilibrium - c - Thermal activity - 3-Two object are in thermal equilibrium if they are in thermal contact because there is : - A no exchange of energy. - b - exchange of energy. - C-a and b together. - 4- Thermometer works under some conditions: - a -It must be in thermal contact and in thermal equilibrium with any system. - b - It must be much smaller than the system. - c - a and b together. - 5-In the thermometer the temperature is defined : - a - linearly proportional to the length of mercury- - b-Inversely proportional to the length of mercury. - C-a and b together. # 1.6 Thermal Expansion of Solids and Liquids[6,7]: - The phenomenon of Thermal Expansion (see Table 1-1 and also see example 1,2 and 6 ): - {As temperature of substance increase, its volume increase). - Def.: - Is the effects of the change in temperature on the average separation between atoms or molecules of any substance. - Examples: - In buildings, concrete highways and bridges. - The three coefficient of linear(X), area (y) and volume(β) thermal Expansion will be shown in the following equations (1.4),(1.5) and (1.6). - Proving: Suppose an object has an initial length L along some direction at some temperature T. Then the length increase by ▲ L for a change in temperature AT - & ΔΤ - = L T - LT-T) - {1.4} - AL - L-L = - A = Lo - 2 - L - LA T & + ما = - A - = L2 = (L+L( )ما + L = L +2 L2 + x²² (ΔΤ(2 - A = L² + 2 × L²AT = A +2 - ΑΔΤ - ΔΑ = Α - Α - γ ΑΔΤ - AL - = LA T - (X) linear thermal expansion - ΔΑ - = ΥΑΔ Τ - (v) Area thermal expansion - AV - = βVOA T - (B) volume thermal Expansion - {1.5} - {1.6} # 1-3 Thermometers and Temperature scales: - Thermometers: - Def.: -Are a devices (Tools) used to measure the temperature of an object or a system. - Ch.: - It must be in thermal contact with any system, in order to get thermal equilibrium. - It must be much smaller than the system, to give accurate measurements of the Temp. of any System. - The physical properties that must be taken into aquent in thermometers: - 1- The volume of a liquid (Mercury). - 2- The length of a solid (a glass capillary tube ). - 3- The electric resistance of a conductor. - 4- The color of a very hot object. - 5-The pressure of a gas held at cons. volume. - 6- The volume of a gas held at cons. pressure. - Notes: - *(Mercury is commonly used in thermometers because its change in volume for every degree of change in temperature is almost constant.) - *One common thermometer is the Mercury (or alcohol) .It consists of a mass of mercury(or alcohol) as shown in Fig. 1-4, that expands in a glass capillary tube when its temperature rises. - *All this properties was applied on this thermometer in addition to this we must know that: - The volume of the liquid varies linearly with its length along the tube. (V & L) ? - The temperature is defined in term of the length of the liquid. (T & L) - The level of the mercury rises as the temperature of the mercury changes from zero degree Celsius {OC°} (the ice point or freezing points of water) to {100C°} (the steam point or boiling point of water). - The distance between marks is then divided into 100 equal segments, each corresponding to a change in temperature of one degree Celsius. # 1.2 Temperature and the Zeros low of Thermodynamics[3]: - Temperature: - Def.:-Is associated with how hot or cold an object feels when we touch it. - Changes which relate to our feeling( Reality-touch) or (Virtual- emotion). - Ch.:-Is measured by quantitative (Scales) and qualitative (Celsius, Kelvin and Fahrenhei.)tools. - Examples: -A metal ice is colder than a package of frozen vegetables (in our hand - Why?). - A cup of hot coffee is cooled when we put apiece of ice in it(in our hand or mouth). - The Zeros low of Thermodynamics (The low of equilibrium): - Def. Thermal contact: - Two object are in thermal contact if energy can be exchanged between them. - Def. Thermal equilibrium: - Two object are in thermal equilibrium if they are in thermal contact there is no exchange of energy. - Def. The Zeros low of Thermodynamics (The low of equilibrium): - If object A and B are separately in thermal equilibrium with a third object C, then A and B are in thermal equilibrium with each other. As shown in Fig. 1-3 a, b,c . - 【Thermal equilibrium i. e at the same temperature. And this is another Def. of Temperature). # Activity (1-5) Free discussion from our life-General Thermal Expansion. - Example 1 - Example 2 -(Rods of the trains) - Applications of Thermal Expansion - Road expansion gaps - Liquid Expansion as thermometer # Put / or x in front of the following: Ans. (2,3,1) - a) The painter used for painting: - 1- Acetone. - 2- Turpentine. - 3- lead. - b) In the thermometer : - 1- Gasoline. - 2- Ethyl . - 3- Mercury. - C) Elements which can be found in the thermostats of certain heating systems: - 1-Brass rod and steel rod. - 2- Bronze rod and steel rod. - 3- Glass rod and steel rod. - d- The gas thermometer works accurately tell the points at which the gas: - 1 - Vaporized. - 2-liquefies. - 3- Saturated. # Example: 1 - a) A steel railroad track has a length of 30 m when the temperature is 0°C what is its length on a hot day when the temperature is 40 °C ? - Solution: - AL - L - = αΔ Τ = {11x 10-6 (°C) -1 } [30000m] [40 °C] =0.013m - L - = L + ∆L = 30 + 0.013 = 30.013m # Example: 2 - a) Estimate the fractional change in volume of the Earths ocean due to an average temperature change of 1 °C . - b) Use the fact that the average depth of the ocean is 4x10³m to estimate the change in depth. When ẞ water= 2.07x 10-4 (°C) -1 - Solution: - AV - = β VAT - AV/V° = β∆т = 2.07x 10-4 (°C) -1 (1 °C )= 2x 10-4 - AL - AL - = α∆T=(β/3) L∆ T = (2.07/3 10-4 (°C) -1) (4000m)(1°C ) - =(6.90 x 10-5 (°C) -1) (4000m)(1°C) = 0.3m # Average Expansion Coefficients ## for Some Materials Near Room Temperature - Average Linear - Material (Solids) - Coefficient (a)(°C) −1 - Average Volume - Material (Liquids and Gases) - Expansion Coefficient (β)(°C) −1 | Material (Solids) | Coefficient (a)(°C) −1 | Material (Liquids and Gases) | Expansion Coefficient (β)(°C) −1 | |:---|:---|:---|:---| | Aluminum | 24 × 10-6 | Acetone | 1.5 × 10-4 | | Brass and bronze | 19 × 10-6 | Alcohol, ethyl | 1.12 × 10-1 | | Concrete | 12 × 10-6 | Benzene | 1.24 × 10-4 | | Copper | 17 × 10-6 | Gasoline | 9.6 × 10-4 | | Glass (ordinary) | 9 × 10-6 | Glycerin | 4.85 × 10-4 | | Glass (Pyrex) | 3.2 × 10-6 | Mercury | 1.82 × 10-1 | | Invar (Ni-Fe alloy) | 0.9 × 10-6 | Turpentine | 9.0 × 10-1 | | Lead | 29 × 10-6 | Aira at 0°C | 3.67 × 10-3 | | Steel | 11 × 10-6 | Heliuma | 3.665 × 10-3 | - Gases do not have a specific value for the volume expansion coefficient because the amount of expansion depends on the type of process through which the gas is taken. The values given here assume the gas undergoes an expansion at constant pressure. - Table (1-1) # 1.8. The unusual Behavior of water [11,12]: - Liquids generally increase in volume with increasing temperature and volume expansion coefficient about ten times greater than those of solids. - As the temperature increases from 0°C to 4°C, water contracts, so its density increases. - The density of water reaches its maximum value of 1000 kg/m³ at 4°C as shown in Fig.(1-9 a, b). - We can use this unusual thermal expansion behavior of water to explain why a pond freezes slowly from the top down. When the atmospheric temperature is between 4°C and 0°C, however the surface water expands as it cools, becoming less dense than the water below it. - As the water freezes, the ice remains on the surface because ice is less dense than water. See example 7,8 a and b,9 a and b. - The ice forms an insulating layer that slows heat loss from the underlying water, offering thermal protection for marine life. - Without the phenomena of buoyancy and the expansion of water upon freezing: - 1- Life on earth may not have been possible. - 2- The freezing of the oceans, turning Earth into an icebound world. # Example:6- A and B - A: The thermal Expansion and some musical wire instruments - Harp - Kaman - Accordion - Kannon - Piyano - B: Another kind of musical instruments: - Electrical- Piyano - Saxophone - Trumpet # Activity(1-7) - Discussion about the thermal Expansion of water and the melting of polar ice : - Example:3 - Simple discussion from researches about the effect of see level rise on Egypt and Arab countries. - Example :4 # 1-7 Applications on the thermal Expansion : - 1-Pyrex-glass: - The Pyrex-glass has a coefficient of linear expansion of about one-third that of the ordinary-glass, so the thermal stress are smaller. - 2-Bimetallic Strips and Thermostats [8]; - Bimetallic Strips: is a simple device that works on the principle of thermal Expansion (brass rod and steel rod), which can be found in the thermostats of certain heating systems Fig.(1-8 a, c). - As the temperature of the strip increase, the two metal expand by different amounts and the strip bends. The change in shape can make or break an electrical connection. Fig.(1-8 b) - 3-Rising Sea Levels[9,10]; - The thermal Expansion of water has a strong effect on the rising ocean levels. Scientistspredict that about one - half of the expected rise in sea level will be caused by thermal Expansion, the remainder will be due to the melting of polar ice. See example 3,4 and5. # Problems and answer: - Choose the correct answer from the following question:2,3,1 - 1-The Pyrex-glass has a coefficient of linear expansion of about one-third that of the ordinary-glass then: - a- The thermal strain are smaller. - b- The thermal stress are smaller. - c - The thermal stress are bigger. - 2-Two sphere are made of the same metal and have the same radius, but one is hollow and the other is solid. Which sphere expands. - a) Solid sphere. - b) Hollow sphere. - c) They expand by the same amount. - d) Not enough information to say. - 3-If you are asked to make a very sensitive glass thermometer, which of the following working fluids would you choose? - A) Mercury 1.8 x10-4. - B) Alcohol. 1.1×10-4 - C) Gasoline 9.6 x104. - 1-What happens to the tension of wires in a piano when the temperature decreases?. # Problems and answer: - 1-Core body temperature can rise from 98.6 °F to 107 °F during extreme example. - a) Convert the given temperatures to Celsius and find the difference. - b) Convert the temperatures to Kelvin, again finding the difference. - Answer: - a) °C = 5/9 (°F-32) = 5/9(98.6-32) = 37°C - ΔΤ°C = 41.77°C- 37°C= 4.77°C - °C - = 5/9 (°F-32) = 5/9 (107-32)= 41,77°C - b) - Δ Τ= 314.92 K - 310.15 K = 4.77K - K= °C + 273.15 = 37°C+273.15 = 310.15 K - =41.77°C + 273.15 = 314.92 K - 2- In example 2, what is the length of the same railroad track on a cold winter day when the temperature is 0 °F(= -18 °C) ? - Answer: - AL - α - = T = {11x 106 (°C) -1} [30000m] [-18 °C] = -5.94 m - L - = L + L = 30 -5.94 = 24.06 m. - 3- A steel ring with a hole having area of 3.99cm² is to be placed on an aluminum rod with crossectional area of 4.0 cm².Both rod and ring are initially at temperature of 35°C. At what common temperature can the steel ring be slipped onto one end of the aluminum rod?. - Answer: - ΔΑ = ΥΑΔΤ = {11x 106 (°C) -1}{ - ΔΑ = ΥΑΔΤ - 3.99 cm²} { 35 °C)= 0.00153615 - = {24 x 10-6 (°C) -1}{ 4 cm²} {35 °C} = 0.00336 - 0.00182385 = (24 x 106 (°C)¹}{ 4 cm²} {Δ Τ} - Δ Τ} - = 18.99°C # Example : 8 a,b - a) - b) - c) # Activity (1-9) Groupe of pictures explain The unusual behavior of water. - Example :7 - Click to add notes