🔍 Key Concepts

• Difference between measuring heat energy content and measuring density or thickness of a liquid • Purpose of a calorimeter in basic physics or chemistry labs • What BTU (British Thermal Unit) actually describes

💭 Think About

• Ask yourself: which instrument is used to find out how much heat is released when a fuel is burned, not just how thick or heavy it is? • Match each option with what it normally measures (for example: does it measure heat, flash point, density, or viscosity?). • Think about where you’ve seen BTU values used (heating systems, boilers). What kind of test would an engineer run to design that system?

✅ Before You Answer

• Be clear that BTU is a unit of heat energy, not thickness or weight. • Identify which listed device is specifically designed to measure heat from combustion, rather than physical properties like density or viscosity. • Eliminate any option that is mainly used for flash point, specific gravity, or flow characteristics instead of heat.