Investigators find out things for themselves. Inventors are engineers who design and make things that will solve problems. Engineering uses a scientific approach and both inventions and investigations depend on good questions, planning, using appropriate materials, collecting data, making sense of the data to verify the results, and presenting the results to others for review.
The National Science Education Standards encourage mastery by students of both engineering and science. Science seeks to find answers by investigating. Engineering seeks to apply science and technology to solve problems. (National Science Education Standards, National Academy of Sciences, p. 192)
Inventions are everywhere. Each time we see a new product, it is somebody’s invention. Fire alarms were developed to quickly to warn everyone of a possible fire first across cities to summon the fire department, then in buildings to save lives. Strobe lights were added to alert hearing impaired people. They will even wake someone out of a sound sleep. Each of these inventions required someone to recognize the problem, define the need, and come up with an invention that solved the problem. The inventions were carefully designed and tested and results were used to determine how well they worked.
While most people think of engineers as those who design buildings, cars, or spaceships, many engineering careers are in the areas of social engineering, urban planning, medicine and many other ways of meeting people’s needs. The design and development of an inexpensive water pump that works in remote parts of Africa has the potential to save millions of lives by providing them clean drinking water.
You may wish to have only an investigation science fair or only an invention science fair (sometimes called an invention convention). If you mix the two kinds of projects, all students will be doing science.
Students who are good problem solvers and especially students who like to think “outside the box” are good candidates to invent something for their science fair project. All students can become better at engineering, but for some, it is the most interesting way to apply their science skills.