Floating and Sinking

• What should you be able to calculate by the end of this video?

  Pressure due to a column of liquid
• What happens when holes are made in the side of a water container?

  Water squirts out, further from the bottom hole
• Why does water from the bottom hole squirt out further than from the top hole?

  Because the bottom water is at higher pressure
• How is the pressure of a column of liquid calculated?

  Pressure = height × density × gravitational strength
• What units are used for pressure in this context?

  Pascal
• What values are provided in the exam for pressure calculations?

  Density and gravitational field strength
• If a freshwater lake has a depth of 8 meters, what is the pressure at the bottom?

  78,400 Pascal
• Why does the pressure of a liquid increase with depth?

  Greater weight of liquid acts downwards
• How does liquid density affect pressure?

  Higher density results in greater pressure
• What is upthrust in relation to floating and sinking objects?

  Resultant force acting upwards on an object
• What must upthrust equal for an object to float?

  Object's weight
• What happens if upthrust is less than the object's weight?

  The object sinks
• What occurs when an object is lowered into water?

  The water level lowers due to displacement
• What is the size of the upthrust acting on an object?

  Equal to the weight of water displaced
• What must an object do to float in water?

  Displace its own weight of water
• What happens when an object is less dense than water?

  It floats after displacing a small volume
• What occurs when an object has the same density as water?

  It floats at the water's surface
• What happens when an object is more dense than water?

  It sinks because it can't displace enough water
• Where can you find questions on pressure in liquids?

  In the vision workbook
• What factors influence whether an object floats or sinks?

  Density of the object and water displaced
• What is the value of gravitational field strength used in calculations?

  9.8 Newtons per kilogram
• How does pressure relate to depth in a liquid?

  Pressure increases as depth increases
• What is the principle of displacement in relation to floating objects?

  Objects displace water equal to their weight