Grade 8 Science - Fluids - Properties of fluids (liquids and gases).
- Owen Nash
- Jan 27
- 4 min read
Discover the exciting world of Grade 8 science with fun and challenging questions that will spark your curiosity and test your knowledge!
Get ready to explore fascinating topics and unleash your problem-solving skills. Are you ready to embark on this thrilling scientific journey? Join us and show off your science prowess by conquering these Grade 8 science challenges!
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1. What is the term for the resistance of a fluid to flow?
a) Density
b) Buoyancy
c) Viscosity
d) Pressure
Answer: c) Viscosity
Explanation: Viscosity is a measure of how much a fluid resists flow. Higher viscosity means the fluid flows more slowly, like honey.
2. Which property of a fluid causes objects to float or sink?
a) Viscosity
b) Buoyancy
c) Surface tension
d) Adhesion
Answer: b) Buoyancy
Explanation: Buoyancy is the upward force exerted by a fluid on an object, which determines whether it floats or sinks.
3. What happens to the pressure in a fluid as depth increases?
a) It decreases.
b) It increases.
c) It remains the same.
d) It fluctuates randomly.
Answer: b) It increases.Explanation: Pressure in a fluid increases with depth because of the weight of the fluid above it.
4. What is the principle that explains why airplanes can fly?
a) Archimedes’ principle
b) Pascal’s principle
c) Bernoulli’s principle
d) Newton’s third law
Answer: c) Bernoulli’s principle
Explanation: Bernoulli’s principle states that as the speed of a fluid increases, its pressure decreases, creating lift under airplane wings.
5. Which of the following is NOT a fluid?
a) Air
b) Water
c) Ice
d) Oil
Answer: c) Ice
Explanation: Fluids are substances that can flow, including liquids and gases. Ice is a solid and cannot flow.
6. What is surface tension?
a) The density of a fluid.
b) The cohesive force at the surface of a fluid.
c) The viscosity of a fluid.
d) The pressure at the bottom of a fluid.
Answer: b) The cohesive force at the surface of a fluid.
Explanation: Surface tension is caused by cohesive forces between molecules at the surface of a liquid, allowing it to resist external forces.
7. What does Archimedes’ principle state?
a) Pressure increases with depth in a fluid.
b) Fluids flow from high pressure to low pressure.
c) An object submerged in a fluid experiences an upward force equal to the weight of the displaced fluid.
d) The volume of a fluid changes with temperature.
Answer: c) An object submerged in a fluid experiences an upward force equal to the weight of the displaced fluid.
Explanation: Archimedes’ principle explains buoyancy and why objects float or sink in fluids.
8. What unit is commonly used to measure pressure in fluids?
a) Liters
b) Pascals
c) Grams
d) Joules
Answer: b) Pascals
Explanation: Pressure is measured in Pascals (Pa), which is defined as force per unit area (N/m²).
9. What happens to a gas when it is compressed?
a) Its density decreases.
b) Its volume decreases.
c) Its mass decreases.
d) Its viscosity increases.
Answer: b) Its volume decreases.
Explanation: Compressing a gas reduces its volume while its mass remains the same, increasing its density.
10. Why do objects feel lighter in water?
a) Water has no gravity.
b) Water exerts an upward buoyant force.
c) Water reduces the object's mass.
d) Water eliminates friction.
Answer: b) Water exerts an upward buoyant force.
Explanation: The buoyant force exerted by water counteracts some of the object's weight, making it feel lighter.
11. Which of the following fluids has the highest viscosity?
a) Water
b) Honey
c) Milk
d) Vegetable oil
Answer: b) HoneyExplanation: Honey has a higher resistance to flow compared to water, milk, and oil, indicating higher viscosity.
12. What property allows water striders to walk on water?
a) Buoyancy
b) Surface tension
c) Adhesion
d) Cohesion
Answer: b) Surface tension
Explanation: Surface tension, caused by cohesive forces, creates a "skin" on the water's surface that can support small insects like water striders.
13. What causes a fluid to exert pressure on its container?
a) Gravitational force
b) Molecular collisions
c) Adhesive forces
d) Surface tension
Answer: b) Molecular collisions
Explanation: Molecules in a fluid are constantly moving and colliding with the walls of their container, creating pressure.
14. Why does warm air rise?
a) Warm air is more viscous.
b) Warm air is denser.
c) Warm air has lower pressure.
d) Warm air is less dense.
Answer: d) Warm air is less dense.
Explanation: As air warms up, it expands and becomes less dense, causing it to rise above cooler, denser air.
15. What is Pascal’s principle?
a) Pressure in a fluid decreases with depth.
b) Pressure applied to a confined fluid is transmitted equally in all directions.
c) Fluids flow from high pressure to low pressure.
d) The volume of a fluid increases with temperature.
Answer: b) Pressure applied to a confined fluid is transmitted equally in all directions.
Explanation: Pascal’s principle is the basis for hydraulic systems, where applied pressure is distributed uniformly.
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