Engineering Design Challenges — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Coming up with many possible solutions is called brainstorming.
Brainstorming gives more options, raising the chance of finding the best design.
2. When one choice gives up speed for strength, that is a trade-off.
Trade-offs help engineers balance competing criteria within tight constraints.
3. A bridge made from straws is cheap but not very sturdy.
Cheaper materials often trade strength, so loads must stay light to work.
4. A paper airplane with wider wings flies slower but more steady.
Wider wings catch more air, increasing lift and steadiness during flight.
5. A water filter using sand and gravel removes particles from dirty water.
Sand and gravel layers trap particles so cleaner water drips through below.
6. Comparing two designs side by side is part of evaluating solutions.
Evaluation uses the same criteria to fairly compare every brainstormed solution.
7. A faster marble run is fun, but it can be less accurate.
Higher speed reduces control, so accuracy and speed are common trade-offs.
8. Choosing one design from many ideas is called selecting a solution.
Selecting means choosing the strongest idea using clear, fair comparison.
9. Engineers often draw two ideas to compare designs side by side.
Sketching designs together makes trade-offs visible before any materials are used.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Bridge project
→ Trade-off between cost and strength
Trade-off between cost and strength
Paper airplane
→ Trade-off between speed and steadiness
Trade-off between speed and steadiness
Water filter
→ Trade-off between flow rate and cleanliness
Trade-off between flow rate and cleanliness
Marble run
→ Trade-off between speed and accuracy
Trade-off between speed and accuracy
Each project balances different criteria, so trade-offs vary by design challenge.