Questions: Testing and Improving

Question 1

Your paper bridge held 15 pennies but your goal was 30. What is the best next step?

• A. Give up because the design failed
• B. Build a completely different bridge from scratch
• C. Look at where the bridge bent or broke, change that part, and test again
• D. Add more pennies and hope it holds

Answer: (C)

The bridge held 15 pennies — it is halfway to the goal, not a failure. The smart engineering move is to observe where it bent or broke, strengthen that specific part, and retest. Starting over throws away the parts that already worked. Adding more pennies without changing anything will just break the bridge.

Question 2

When improving a design, you should change as many things as possible at once to save time.

• T. True
• F. False

Answer: False

If you change five things at once and the design gets better, you do not know which change helped — and some of the changes might have actually made things worse but were hidden by the one good change. Change one thing at a time, test, and see the effect. This is slower per round but much faster overall because you learn what actually works.

Question 3

Why is it important to write down your test results instead of just remembering them?

Model answer: Written records let you compare results across multiple tests accurately. Memory is unreliable — you might forget how the first version performed by the time you are testing the third version. Written data helps you see whether each change actually improved the design.

Engineering is evidence-based. Without written records, you are relying on feelings and impressions, which can be misleading. A simple table showing 'version 1 held 15 pennies, version 2 held 22 pennies, version 3 held 31 pennies' tells a clear story of improvement that memory alone cannot provide.