🔍 Key Concepts

• Relationship between temperature and volume for most liquids, including fuel oil • How viscosity (thickness/resistance to flow) changes when a liquid is heated • Meaning of specific gravity and whether density usually increases or decreases with heat

💭 Think About

• Think about what happens to fuel oil in storage tanks on a cold day versus a hot day: does it flow more easily or more slowly? • If the same mass of oil is heated, what tends to happen to its density and the space it occupies? • Does heating usually make a liquid heavier per unit volume or lighter per unit volume?

✅ Before You Answer

• Be clear on the definition of viscosity (thicker vs thinner when heated) • Remember that specific gravity is directly related to density (heavier or lighter than water) • Consider what happens to the volume of most liquids when their molecules move faster due to heat