*Note: This is an abbreviated Project Idea, without notes to start your background research, a specific list of materials, or a procedure for how to do the experiment. You can identify abbreviated Project Ideas by the asterisk at the end of the title. If you want a Project Idea with full instructions, please pick one without an asterisk.
How does the air pressure in a tire affect the rolling resistance of a bicycle or wheelbarrow? Do you need more or less effort to move the bicycle (or wheelbarrow) as the air pressure is changed? Use a tire pressure gauge to monitor air pressure (don't exceed the recommended tire pressure). For the bicyle, you could probably use a spring scale to measure how much force is needed to pull the bicycle along (have a friend lightly touching the bike to keep it balanced). Quantifying the force needed to move the wheelbarrow will be a bit more difficult. You may have to resort to a 1–5 rating scale (e.g., where 1="I can do this all day," 2="takes a bit of effort," 3="a good workout," 4="pushing myself pretty hard," and 5="maximum effort.") For more advanced students, can you explain your results in terms of frictional forces?
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If you like this project, you might enjoy exploring these related careers:
Mechanical engineers are part of your everyday life, designing the spoon you used to eat your breakfast, your breakfast's packaging, the flip-top cap on your toothpaste tube, the zipper on your jacket, the car, bike, or bus you took to school, the chair you sat in, the door handle you grasped and the hinges it opened on, and the ballpoint pen you used to take your test. Virtually every object that you see around you has passed through the hands of a mechanical engineer. Consequently, their skills are in demand to design millions of different products in almost every type of industry.
Mechanical Engineering Technician
You use mechanical devices every day—to zip and snap your clothing, open doors, refrigerate and cook your food, get clean water, heat your home, play music, surf the Internet, travel around, and even to brush your teeth. Virtually every object that you see around has been mechanically engineered or designed at some point, requiring the skills of mechanical engineering technicians to create drawings of the product, or to build and test models of the product to find the best design.
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