Week 9 of March 1st
Objectives:
1. Students will write a long constructed response on how an internal combustion engine works.
2. Students will be assessed on their knowledge of the laws of pressure
Agenda:
1. Pressure power point
2. How an internal combustion engine works
3. Boyles law, and see how different factors effect pressure
4. Excursion: Scuba Trip. At Underwater Phataseas they will review some of the laws of pressure that apply to scuba diving
5. Pressure Worksheet #3
6. Potato gun
7. Pressure quiz on Friday
Website on how engines work:
Notes:
A very common variant of the internal combustion engine is the four stroke engine. These engines have four "strokes" for each combustion cycle. These engines are primarily used in automobiles but have recently found their way into motorcycles, boats, and even snow machines. The four "strokes" of these engines are as follows.
1. Intake: The intake valve (on the left top of the cylinder) opens allowing fresh oxygen rich air mixed with fuel to enter the cylinder.
2. Compression: The piston is pushed upward by the flywheel's momentum compressing the air/fuel mix.
3. Combustion: As the piston reaches the top of its stroke or TDC the spark plug fires igniting the mixture. Due to the high compression of this mixture (typically around 190 PSI in a typical engine) it is very volatile and it explodes when the spark is introduced. This pusehs the piston downward and produces power.
4. Exhaust: After the Air/Fuel mix has been burnt the remaining chemicals in the cylinder (water and CO2 for the most part) must be removed so that fresh air can be brought in. As the piston goes back up after combustion the exhaust valve (right top of cylinder) opens allowing the exhaust gasses to be expelled.
Ideally an engine takes in Air (Oxygen and Nitrogen) and fuel (hydrocarbons) and produecs CO2, H2O, and the N2 just passes straight through. The chemical equation is as follows.
1. Intake: The intake valve (on the left top of the cylinder) opens allowing fresh oxygen rich air mixed with fuel to enter the cylinder.
2. Compression: The piston is pushed upward by the flywheel's momentum compressing the air/fuel mix.
3. Combustion: As the piston reaches the top of its stroke or TDC the spark plug fires igniting the mixture. Due to the high compression of this mixture (typically around 190 PSI in a typical engine) it is very volatile and it explodes when the spark is introduced. This pusehs the piston downward and produces power.
4. Exhaust: After the Air/Fuel mix has been burnt the remaining chemicals in the cylinder (water and CO2 for the most part) must be removed so that fresh air can be brought in. As the piston goes back up after combustion the exhaust valve (right top of cylinder) opens allowing the exhaust gasses to be expelled.
Ideally an engine takes in Air (Oxygen and Nitrogen) and fuel (hydrocarbons) and produecs CO2, H2O, and the N2 just passes straight through. The chemical equation is as follows.
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