The EGR system routes a number of the exhaust gases (6 ? 10%) from the EGR valve, last on the Intake System, and ultimately within the combustion chamber. The exhaust gases are inert i.e. they cannot burn in the combustion chamber; also, the exhaust gases take up a number of the space which would preferably be taken with the intake air. This reduces the volume of intake air readily available for the combustion process during each Power Stroke; which in turn decreases the peak combustion temperatures. This brings about lower NOx emissions. 9. Their emotional appeal Creative photo art projects around the Ugly Duckling, a children's book, can open students' eyes to seeing life within an entirely new way. In this lesson, students will photograph old, rusty, discarded and unusually placed items found everywhere. Using photo enhancing software, they're going to then develop a picture that can take what others may have seen as ugly, turning it into something beautiful. (Note: If the school doesn't have photo enhancing software, then Gimp, the industry free download, works extremely well.)