A magnet tool will help a mechanic pick up steel bolts safely. Which is an important requirement for this magnetic solution?
- It must only work if the bolts are painted blue
- It must be safe to use and not pinch fingers (correct answer)
- It must pull bolts from any distance, even 1 mile away
- It must also fix broken engines by itself
Explanation: This question tests ability to define criteria and constraints for magnetic solutions (3-PS2-4). Criteria define what the solution must do while constraints identify limitations. The problem is creating a safe magnetic tool for mechanics to pick up steel bolts. Answer A correctly identifies an important safety criterion: the tool must be safe to use and not pinch fingers, addressing a realistic concern when using strong magnets in tools. Answer B suggests an impossible constraint since magnetic force decreases rapidly with distance, Answer C adds unrelated functionality beyond the stated problem, and Answer D introduces an arbitrary color requirement. When defining criteria for magnetic tool solutions, students should prioritize safety considerations, ensure criteria are realistic given magnetic properties, and focus on the specific problem to be solved.