🔍 Key Concepts

• Magnetic compass construction and what a binnacle actually is • How nearby magnetic materials affect a compass card • Difference between features that are "nice to have" (corrosion resistance, weatherproofing) vs. what the compass fundamentally requires to work correctly

💭 Think About

• Ask yourself: What will happen to a magnetic compass if the structure surrounding it can be magnetized? How would that affect the readings? • Which option, if missing, would MOST seriously interfere with the compass’s primary job: giving you a reliable magnetic heading? • Think about the purpose of the binnacle: Is it mainly structural/protective, or does it also have to avoid changing the compass’s magnetic environment?

✅ Before You Answer

• Verify which property directly affects accuracy of the magnetic needle/card rather than durability or convenience. • Check your basic physics: what kinds of materials disturb a magnetic field, and what must the compass housing avoid? • Before choosing, ask: If this property were missing, would the compass still be able to give a correct heading, assuming calm seas and good maintenance?