"Thermal Engine and Social Development" Internal Energy and Heat Engine PPT Courseware

Description

"Thermal Engine and Social Development" Internal Energy and Heat Engine PPT Courseware

learning target

1. Understand the energy conversion process during the operation of heat engines.

2. Understand the working principle and working process of gasoline engines and improve your ability to read pictures.

3. Through the analysis and discussion of issues such as the efficiency of heat engines and heat engines and the environment, we will establish awareness of efficiency and environmental protection.

Core test point: the four strokes of an internal combustion engine.

Preview before class

1. A heat engine is a machine that converts _______ energy into _______ energy. Common heat engines include _______, _______, and _______.

2. The four strokes of a gasoline engine include: _______, _______, _______, _______.

3. During the compression stroke of the gasoline engine, _______ energy is converted into _______ energy; during the power stroke, the _______ energy is converted into _______ energy.

4． Regarding the efficiency of heat engines, which of the following statements is correct ( )

A. The more useful work a heat engine does, the higher its efficiency must be.

B. The less fuel a heat engine consumes, the higher its efficiency must be.

C. When a heat engine does a certain amount of useful work, the less fuel it consumes, the higher the efficiency must be.

D. The faster the heat engine does work, the higher the efficiency must be

Lectures in class

Knowledge point 1. Heat engine

(1) Heat engine: The engines of cars, ships and airplanes are devices that convert the internal energy released when fuel is burned into mechanical energy. This device is called a heat engine. There are many types of heat engines, such as: steam engines, internal combustion engines (gasoline engines, diesel engines), gas turbines, jet engines, rocket engines, etc. The energy conversion process of all heat engines is the same when they are working, that is, the chemical energy of the fuel is converted into internal energy through combustion, and then the internal energy is converted into mechanical energy through work. Therefore, a heat engine is a machine that uses internal energy to do work, or a heat engine is a machine that converts internal energy into mechanical energy.

(2) Experimental exploration: How does a heat engine convert internal energy into mechanical energy?

As shown in the picture, put some water in the test tube, plug the mouth of the test tube with a cork, and heat it on an alcohol lamp to make the water boil. The water vapor will flush out the cork. In this experiment, the burning process of alcohol is the process of converting the chemical energy of alcohol into internal energy. This part of the internal energy is transferred to water and water vapor, causing the temperature to rise and the internal energy to increase. When the water vapor flushes out the stopper, the water The internal energy of the steam is converted into the mechanical energy of the plug.

Exploration and conclusion: The above device is a simple and primitive heat engine. Its working process is: fuel combustion, chemical energy is converted into internal energy, and the internal energy is transferred to the working material through heat transfer. The internal energy of the working material increases and the temperature rises. , pushing the piston to do external work and converting internal energy into mechanical energy.

(3) Types of heat engines include steam engines, gasoline engines, diesel engines, etc.

(4) A heat engine in which fuel is burned directly in the engine cylinder to generate power is called an internal combustion engine. Common internal combustion engines include gasoline engines and diesel engines.

[Typical example 1] Among the following devices, the one that can convert internal energy into mechanical energy is ( )

A． Heat engine b. Generator c. Electric motor D. hair dryer

[Exercise 1] The common power machinery of automobiles is internal combustion engines. From the perspective of energy conversion, an internal combustion engine is a machine that converts internal energy into _____ energy.

Knowledge point 2. Gasoline engine

(1) Gasoline engine: It is a heat engine that uses the gasoline burned in the cylinder to produce high-temperature and high-pressure gas to push the piston to do work.

(2) Structure: Consists of intake valve, spark plug, exhaust valve, cylinder, piston, connecting rod, crankshaft, etc. As shown below.

(3) Working process: The working cycle of most gasoline engines consists of four strokes, namely the suction stroke, compression stroke, power stroke and exhaust stroke. The working process is as shown in the table below.

Notice:

(1) The flywheel rotates twice in each working cycle to complete a power stroke.

(2) In a working cycle, only the gas does work in the power stroke. The other three auxiliary strokes not only do no work, but also consume mechanical energy.

(3) The power stroke provides energy for the other three strokes, and the other three strokes provide the basis for the work of the power stroke.

(4) Relying on the inertia of the flywheel (the kinetic energy stored in the flywheel) to complete the suction stroke, compression stroke and exhaust stroke.

Chapter 12 Review Lesson

Test Point 1 Internal Energy (High Frequency Test Point)

Analysis of test points: This test point is a high-frequency test point for the Guangdong High School Entrance Examination. The focus of the test is the method of changing the internal energy. Knowledge points to be mastered: (1) There are two methods of changing the internal energy of an object: one is work, and the other is heat transfer. .Work: when an object does work on the outside, the internal energy decreases; when the outside world does work on the object, the internal energy increases. Heat transfer: when the object absorbs heat, the internal energy increases; when the object releases heat, the internal energy decreases. (2) Internal energy and temperature Relatedly, the higher the temperature of the object, the faster the molecules move and the greater the internal energy.

1. (2013 Guangdong, 5, 3 points) Regarding temperature, internal energy and heat, which of the following statements is correct ( )

A． The warmer the object, the more heat it contains

B． When the temperature of an object is 0°C, the internal energy is zero

C. Rubbing your hands together will not increase the internal energy of your hands

D. Internal energy can be automatically transferred from high-temperature objects to low-temperature objects

2. (2014 Guangdong, 4, 3 points) Regarding temperature, internal energy, heat and work, which of the following statements is correct ( )

A． The internal energy of an object increases because it must have absorbed heat from the outside world.

B． An ice cube at 0°C has no internal energy

C. Work can change the internal energy of an object

D. When an object releases heat, its temperature must decrease

3. (2009 Guangdong, 11, 2 points) Rubbing hands can increase the temperature of the hands, which is to use ________ to increase the internal energy of the hands; using an electric water heater to heat water is to use ______ to make the water Internal energy increases.

1. (2006 Guangdong, 6, 3 points) The schematic diagram of the four strokes of a single-cylinder four-stroke internal combustion engine is shown in Figure 2. The following is the correct sequence of the four strokes of a working cycle of this internal combustion engine ( )

A． C, D, B, A B. B, D, A, C

C. B, A, D, C D. A, B, C, D

2. (2013 Guangdong, 12, 3 points) Among the four strokes of a gasoline engine, the _____ stroke is where mechanical energy is converted into internal energy. As shown in the figure, the gasoline engine is undergoing a _____ stroke.

Test point 4. Calorific value calculation, heat engine efficiency

Analysis of test points: The focus of this test point is on the calculation of calorific value. When solving the problem, you must carefully review the question and use the formula Q=mq to answer the question. The efficiency of the heat engine has not been tested in recent years, so you should also pay attention to it when reviewing.

1. (2011 Guangdong, 9, 1 point) The energy released by the complete fission of 1kg uranium nucleus exceeds the energy released by the complete combustion of 2000t coal. If the calorific value of coal is 3×107J/kg, then the energy released by the complete fission of 1kg of uranium is at least __________J.

2. (2013 Guangdong, 12, 1 point) It is known that the calorific value of gasoline is 4.6×107J/kg, then the heat released by complete combustion of 100g of gasoline is __________J.

Keywords: internal energy and heat engine teaching courseware, heat engine and social development teaching courseware, Guangdong and Shanghai version ninth grade physics PPT courseware download, ninth grade physics slide courseware download, internal energy and heat engine PPT courseware download, heat engine and social development PPT courseware Download, .PPT format;

For more information about the PPT courseware "Heat Engines and Social Development Internal Energy and Heat Engines", please click the "Heat Engines and Social Development ppt Internal Energy and Heat Engines ppt" tag.

"Heat Engine and Social Development" Internal Energy and Heat Engine PPT Courseware 3:

"Heat Engines and Social Development" Internal Energy and Heat Engines PPT Courseware 3 Teaching Objectives 1. Know the working principle of heat engines and energy conversion. 2. Understand the working principle and working process of gasoline engines. 3. The difference between gasoline engine and diesel engine. 4. Improve thermal engine efficiency. Test Preview 1 Understand...

"Heat Engine and Social Development" Internal Energy and Heat Engine PPT Courseware 2:

"Thermal Engine and Social Development" Internal Energy and Thermal Engine PPT Courseware 2 1. Heat engine Steam engine Diesel engine Gas turbine Gasoline engine Jet engine Rocket engine. 2: Working process (1) When the internal combustion engine is working, the four strokes start over and over again. In a working cycle of the internal combustion engine...

File Info

Update Time: 2024-07-03

This template belongs to Physics courseware Guangdong and Shanghai Edition Ninth Grade Physics Volume 1 industry PPT template

Preview