What do engineers do?
An engineer solves problems by designing and building things. Engineers design bridges, phones, toys, shoes and even spoons. Scientists ask "how does the world work?" Engineers ask "how can I solve this problem?"
Engineers follow a set of steps called the engineering design process. The steps go in a loop, because the first try is rarely the best.
Step 1: Define the problem
Start by saying exactly what the problem is. Who has the problem? What would a good solution do?
The things a solution must do are called criteria. The limits you must work within are called constraints.
| Problem | Criteria (it must…) | Constraints (limits) |
|---|---|---|
| Keep an egg safe when dropped | Stop the egg from cracking from 2 m | Only paper, tape and straws; 20 minutes |
| Build a bridge for toy cars | Hold 10 toy cars; span 30 cm | 30 craft sticks and glue |
Step 2: Imagine and plan
Brainstorm many ideas. Don’t throw any away yet. Sketch them. Then pick the one that best meets your criteria and fits your constraints. Draw a labelled design that shows the materials and how they fit together.
Step 3: Build
Build a prototype. A prototype is a first model of your design. It doesn’t have to be pretty. It just has to be good enough to test.
Step 4: Test
Test your prototype to see whether it meets the criteria. Make the test fair and record what happens.
- Did the egg crack?
- How many cars did the bridge hold before it bent?
Step 5: Improve
Look at what went wrong. Ask: "Where did it fail? Why?" Then improve your design and test again. Engineers often go through this loop many times.
| Try | Change made | Result |
|---|---|---|
| 1 | Plain paper cup around egg | Egg cracked |
| 2 | Added straw "springs" under the cup | Small crack |
| 3 | Added a paper parachute | Egg safe! |
Failure is not a bad thing in engineering. Every failure shows you how to make the design better.
Step 6: Share
Engineers share their designs so others can learn from them. Explain your criteria, show your prototype, describe your tests and say what you changed.
In the real world
Car engineers crash-test cars with dummies inside, then improve seatbelts and airbags. Phone designers build dozens of prototypes before choosing one. The first airplanes crashed many times before the Wright brothers’ design flew in 1903.
Common mistakes
- Skipping the planning step and building right away.
- Testing once and stopping.
- Forgetting the constraints, such as using materials you weren’t allowed.
Try it yourself
Challenge: Build the tallest tower you can that holds up a tennis ball for 10 seconds.
- Materials: 20 sheets of paper and 1 metre of tape.
- Sketch two ideas, then pick one.
- Build, test and measure the height.
- Improve your tower and test again. Did it get taller?
Quick recap
- Engineers design solutions to problems.
- Criteria are what the solution must do; constraints are the limits.
- A prototype is a first model built for testing.
- Engineers test, find what failed and improve, again and again.
- Sharing designs helps everyone learn.