🔍 Key Concepts

• Specific gravity as a measure of liquid density compared to water • Common instruments used to measure the density of a liquid in a tank or cell • What each listed device is normally used for in a lab or engineering context

💭 Think About

• Which of these devices is specifically designed to float in a liquid and show how dense it is? • Which choices are clearly for chemical analysis (like acidity or titration) rather than for directly measuring density? • Think about what tool a mechanic or engineer would actually use when checking the condition of a lead‑acid battery on board.

✅ Before You Answer

• Match the device to its normal purpose in basic science/engineering, not just on ships • Ask: does this device measure density/specific gravity directly or something else (like pH or volume)? • Eliminate any option that clearly measures acidity (pH) or is mainly for adding or measuring liquid volumes in lab experiments.