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A car is a complicated piece of machinery with a simple purpose: motion. At its heart, all that motion is driven by a series of explosions inside the engine’s cylinders. But how do the cylinder dimensions help determine a car’s power?

In this lesson students calculate the total volume of the cylinders in different engines and relate volume to horsepower. They also examine how modifying an engine can affect its performance.

Students will

  • Given an engine cylinder’s bore (width) and stroke (height), calculate the volume of a single cylinder
  • Calculate the total displacement of engines in different vehicles
  • Examine the relationship between engine displacement and horsepower
  • Determine which would have a larger effect on power, a change in bore or an equivalent change in stroke
  • Find different combinations of bore/stroke modifications that would lead to the same increase in power
  • Discuss the practical limitations of engine modification and limits on power production

Before you begin

Students should be able to calculate a cylinder’s volume given its diameter and height. The should also be familiar with unit rates, e.g. the meaning of a phrase such as, “15 cubic centimeters per horsepower.”

Common Core Standards

Content Standards
Mathematical Practices