D. Maintenance and Troubleshooting

The statement that "anything that can go wrong will go wrong," known as Murphy's Law, has been attributed to aerospace engineer Edward Murphy, who first used the expression (or something like it) in 1949 to explain the failure of measurement equipment for a high-speed rocket sled (Spark, 2006). Murphy's Law has come to characterize everyday life, not only for engineers but also for everyone in modern society. Today humans are surrounded by and dependent upon complicated devices that seem to go wrong at critical times. It is not uncommon to experience more than one technological failure in a single day, whether it's a car that fails to start, a cell phone without "bars," or something as simple as an eyeglass frame with a lens that repeatedly pops out.

A person who is literate in technology and engineering is aware that all technological systems fail at one time or another and is therefore equipped with a foundation of concepts and skills that can be applied either to correct failed devices and systems or to prevent the failure from occurring in the first place. The most important of these concepts and skills are maintenance and troubleshooting.

In the 2014 NAEP Technology and Engineering Literacy Framework, the term maintenance has a very specific meaning: It refers to keeping technological devices and systems in good condition so as to extend their useful life and reduce the number of breakdowns. For example, maintenance can refer to the regular upkeep of technologies so that they are less likely to fail, such as periodically replacing the oil in a car engine, cleaning the lint filter of a clothes dryer, or running regular software updates on a computer operating system.

Troubleshooting, by contrast, refers to a systematic method of dealing with failures once they have occurred. It is common to begin troubleshooting by ascertaining the nature of the problem. For example, in the case of a television that has failed, it is important to determine if some parts of the device are still working. Is the power light on? Is the sound missing, or the picture, or both? If the power light is not on, it may be unplugged. If that is not the problem, the next step may be to isolate the problem to one part of the system. For instance, the problem may not be the TV at all but rather a faulty DVD, which can be tested by inserting a different DVD. A third step might be to learn as much as possible about how the system functions, either from an owner's manual or from someone who is familiar with such systems. Troubleshooting is not confined to mechanical and electronic systems. Artists, writers, and musicians also encounter problems that require troubleshooting.

Perhaps the most distinctive feature of troubleshooting is coming up with a number of different ideas about what may have caused the failure and then using a logical method for narrowing down the possible causes with a series of either-or tests, sometimes called a fault tree, until the source of the problem is discovered.

When designing technological systems it is important for engineers to consider maintenance costs, since people may wish to pay a little more for a product that is less expensive to maintain. Similarly it is important for engineers to anticipate ways in which complicated products and systems are likely to break down and to build into the design simple ways to troubleshoot and fix the most common causes of failure. Factors to consider may include maintenance costs, available technologies, time until obsolescence, and environmental impacts.

Key principles in the area of Maintenance and Troubleshooting that all students can be expected to understand at increasing levels of sophistication are as follows:

• Tools and machines must undergo regular maintenance to ensure their proper functioning.
• Troubleshooting is a systematic approach to diagnosing a technological failure.
• Taking into account the entire life cycle of a product is an important part of designing.

At the fourth-grade level students should know that it is important to care for tools and machines so they can be used when they are needed. For example, tools should not be left out in the rain, and electronic equipment should be handled with care. Students should also know that if something does not work as expected, it is possible to find out what the problem is in order to decide if the item should be replaced or determine, if possible, how to fix it. They should know that some items, such as ballpoint pens, are designed to be disposable, and they should be able to discuss the disposal or recycling of such items.

Eighth-graders should be familiar with the concept of maintenance and should understand that failure to maintain a device can lead to a malfunction. They should also be able to carry out troubleshooting, at least in simple situations. For example, they should be able to safely use tools and instruments to diagnose a problem in a device, and they should be able to consult manuals or talk to experienced individuals to learn how the device works. They should be able to test various ideas for fixing the device. And they should be able to analyze an item's life cycle and discuss the impact of disposing of an item that has reached the end of its useful life.

By twelfth grade students should know that many devices are designed to operate with high efficiency only if they are checked periodically and properly maintained. They should also have developed the capability to troubleshoot devices and systems, including those that they may have little experience with. Students at this level should also be able to think ahead and to identify and document new maintenance procedures so that a malfunction is less likely to occur again. They should be able to weigh the costs and benefits of maintaining an existing item versus disposing of it and obtaining a newer replacement, with particular attention paid to lessening the environmental impact of disposing of obsolescent or non-functioning products.