Pressure and pressure differences in fluids (physics only) revision notes

Pressure and pressure differences in fluids (physics only)

Pressure and pressure differences in fluids (physics only) revision notes for AQA GCSE Physics 8463 Unit 4.5 Forces. Use these notes to connect each learning objective to equations, units, diagrams, graphs and physical reasoning.

Focus 1: In Pressure on a surface (physics only), students revise how to (Physics only) Define pressure as force per unit area. Key terms include pressure, force, area, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 2: In Pressure on a surface (physics only), students revise how to (Physics only) Use the equation pressure = force normal to a surface divided by area of that surface. Key terms include pressure, force, surface, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 3: In Pressure on a surface (physics only), students revise how to (Physics only) Calculate pressure from force and area. Key terms include pressure, force, area, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 4: In Pressure on a surface (physics only), students revise how to (Physics only) Calculate force from pressure and area. Key terms include pressure, force, area, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 5: In Pressure on a surface (physics only), students revise how to (Physics only) Calculate area from force and pressure. Key terms include pressure, force, area, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 6: In Pressure on a surface (physics only), students revise how to (Physics only) State that pressure is measured in pascals. Key terms include pressure, pascal, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 7: In Pressure on a surface (physics only), students revise how to (Physics only) Explain why a smaller area gives a greater pressure for the same force. Key terms include pressure, force, area, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 8: In Pressure on a surface (physics only), students revise how to (Physics only) Explain why a larger area gives a smaller pressure for the same force. Key terms include pressure, force, area, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 9: In Pressure on a surface (physics only), students revise how to (Physics only) Apply pressure ideas to everyday examples such as sharp blades, snowshoes or high heels. Key terms include pressure and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 10: In Pressure on a surface (physics only), students revise how to (Physics only) Apply MS 3b and MS 3c skills when rearranging pressure equations. Key terms include pressure and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 11: In Pressure in liquids (physics only), students revise how to (Physics only) Explain that pressure in a liquid increases with depth. Key terms include depth and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 12: In Pressure in liquids (physics only), students revise how to (Physics only) Explain that pressure in a liquid acts in all directions. Key terms include physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 13: In Pressure in liquids (physics only), students revise how to (Physics only) Explain that pressure in a liquid is caused by the weight of liquid above. Key terms include physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 14: In Pressure in liquids (physics only), students revise how to (Physics only) Use the equation pressure = height of column x density x gravitational field strength. Key terms include density, gravitational field strength, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 15: In Pressure in liquids (physics only), students revise how to (Physics only) Calculate pressure from depth, density and gravitational field strength. Key terms include depth, density, gravitational field strength, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 16: In Pressure in liquids (physics only), students revise how to (Physics only) Calculate depth from pressure, density and gravitational field strength. Key terms include depth, density, gravitational field strength, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 17: In Pressure in liquids (physics only), students revise how to (Physics only) Identify density in kilograms per metre cubed and depth in metres when using p = hρg. Key terms include depth, density, p = hρg, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 18: In Pressure in liquids (physics only), students revise how to (Physics only) Explain why pressure differences in a liquid produce an upwards force on submerged objects. Key terms include pressure difference and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 19: In Pressure in liquids (physics only), students revise how to (Physics only) Describe upthrust as the upward force on an object in a fluid. Key terms include upthrust and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 20: In Pressure in liquids (physics only), students revise how to (Physics only) Explain floating and sinking in terms of weight and upthrust. Key terms include upthrust and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 21: In Pressure in liquids (physics only), students revise how to (Physics only) Apply MS 3b and MS 3c skills when rearranging liquid-pressure equations. Key terms include physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 22: In Atmospheric pressure (physics only), students revise how to (Physics only) Describe atmospheric pressure as pressure caused by air particles colliding with surfaces. Key terms include atmospheric pressure, air particles, and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 23: In Atmospheric pressure (physics only), students revise how to (Physics only) Explain that the atmosphere becomes less dense at greater height. Key terms include atmosphere and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 24: In Atmospheric pressure (physics only), students revise how to (Physics only) Explain why atmospheric pressure decreases as height above Earth's surface increases. Key terms include atmospheric pressure and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 25: In Atmospheric pressure (physics only), students revise how to (Physics only) Link atmospheric pressure to the weight of air above a surface. Key terms include atmospheric pressure and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Focus 26: In Atmospheric pressure (physics only), students revise how to (Physics only) Explain why pressure differences can produce forces in gases. Key terms include pressure difference and physics only. A good answer states the relevant quantity, uses units such as N, kg, m, s, Pa, Nm, m/s or kg m/s where needed, and links the process or calculation to a clear physical consequence.

Exam technique: for calculations, write the formula, substitute values with units, calculate carefully and state the final unit. For graph questions, identify whether the gradient or area is being used. For explanations, name the force or motion quantity and keep nearby concepts distinct.