DID YOU KNOW…?
A car that is energy efficient can travel farther on the same amount of gas, which saves the driver money and decreases air pollution. Also, gasoline is made from oil, which is a non-renewable energy source. This means that when it is used up, no more is available. For these reasons, engineers are continually figuring out ways to make cars more energy efficient. Aerodynamics is one example (see https://youtu.be/AXjiThF1LXU for more information.)
The automobile company, Rolls-Royce, has produced many cars that are considered of poor fuel efficiency by the United States Department of Energy. Similar to automotive engineers, your task is to build a prototype to test the effect of different variables to report recommendations to the company. The prototype should travel along a straight path down a ramp and travel as far as possible with a minimum of 8 feet.
What are variables you might ask? Let’s explore this with an interactive video that uses MythBuster experiments to explain.
MATERIALS IN KIT
- 12 Lifesavers Mints (individually wrapped)
10 index cards
- 8 straws
- 8 toothpicks
- 20 popsicle sticks
- Masking tape
- Tape measure
- 30 pennies
- Items around your home
What can we learn from others? Let’s watch a few videos to find out. Stop the videos as needed to take notes on what you notice that you might include in your own designs.
Brainstorm and sketch 2-3 car designs. For each, make a list of materials and you can only use material from the kit in your design. How do you think the body of the car will make a difference?
Pick one of your designs from Step 2 and build your car prototype. But wait? How are you going to test your prototype? We need a ramp! Determine a location inside or outside your home to test the prototype. Construct a ramp using material from your home environment. How will you secure the ramp?
Does your ramp need support?
STEP 4—PILOT TEST & IMPROVE
Let’s test your prototype by sending it down the ramp 3 times. What did you notice? How far did it travel? Did it travel in a straight line? What can be improved? How is this based on your observations? Make these changes to your prototype. Keep testing and redesigning the prototype until you are satisfied.
STEP 5—TEST #1
Let’s test how weight changes the distance traveled by adding or removing pennies each trial. How many trials? At least six. In this test, what is the independent variable and the dependent variable? Let’s keep track of our test through a table.
|# of pennies
DID YOU KNOW…?
Pennies weigh different amounts depending on the year the penny was made. Pennies made before 1982 are made of 95% copper and 5% zinc. A copper penny weighs 3.11 grams or 0.109702 ounces. Pennies made in the year of 1982 and after are made of 97.5% zinc and 2.5% copper. A zinc penny weighs 2.5 grams or 0.0881849 ounces.
STEP 6—TEST #2
Let’s conduct a new test on how the number of wheels change the distance traveled. Make a prediction about what you think will happen to the distance the car will travel based on changes to the wheels. How many trials? At least three. Let’s keep track of our test through a table.
|# of wheels
There are additional variables that you can consider before making recommendations to Rolls Royce. As an engineer, remember to document your test(s).
- Change the size of the wheel using objects in your home.
- Texture of the wheel. Wrap the wheel with material in your home (e.g., aluminum foil).
- Position and balance of the wheels.
How do you think the body of the car might change your results? Choose another design from Step 2 and replicate or copy your tests. How are your results similar and/or different? For example, might the size of the prototype make a difference (e.g., large truck versus a small sports car)? Support using evidence from your charts and your observations as an engineer.
Based on the results from your tests, what recommendations would you make to Rolls Royce regarding changes they should make to increase their fuel efficiency ratings? Support using evidence from your charts and your observations as an engineer.
DID YOU KNOW…?
- The first engine powered car was built in Mannheim, Germany by Karl Benz in 1885. Between 1888 and 1893 they sold a whopping 25 units.
- On average, every American will spend approximately two whole weeks of their life stopped at red lights.
- The first speeding ticket ever issued was in 1902, when most cars could barely reach 45mph.
- In 1939 the San Antonio Light wrote about future cars that could be folded into a neat and tidy suitcase-sized package. Got that one a little wrong.
For more interesting facts about automotive engineers, check out https://automotive-engineering.weebly.com/index.html
DID YOU ALSO KNOW…?
Mechanical engineers can work in various industries—manufacturing, aeronautics, robotics, oh, and yes, automobiles—as they have an understanding of how machines work. Mechanical engineers are part of a team that designs, tests, and improves parts of a car to pass safety standards. Henry Ford, Karl Benz, and Nikola Tesla were mechanical engineers and known for revolutionizing the automobile industry