🔍 Key Concepts

• Behavior of hydraulic oil under high pressure conditions • Relationship between pressure, volume, and viscosity in fluids • Definition and meaning of pour point for lubricating and hydraulic oils

💭 Think About

• Think about what typically happens to a liquid’s volume when you increase the pressure on it. Does it expand or compress? • Consider whether viscosity (thickness) is mainly affected by pressure or by temperature in normal machinery operation. • Ask yourself what the pour point measures and whether normal operating pressure would realistically change that property.

✅ Before You Answer

• Confirm whether liquids are compressible or nearly incompressible under high pressure and what that implies for volume. • Verify if viscosity is more sensitive to changes in temperature or pressure in practical hydraulic systems. • Check your understanding of pour point: it is usually related to temperature, not pressure—make sure that fits with the scenario.