Floating and Sinking
What is the name of the upward force that acts on floating objects?
Upthrust
Which two measurements are needed to calculate density?
Mass and volume
What is the name for the fluid pushed out of the way by an object?
Displacement
In which two states of matter does convection occur?
Liquids and gases
Pressure is caused by a force acting over what?
An area
What must be true about an object’s density for it to float in a liquid?
Its density must be lower than the liquid’s density
What is the equation for density?
Density = mass ÷ volume
What is the upthrust on an object equal to?
The weight of the fluid displaced
Why does warm fluid rise?
It becomes less dense
How does pressure change as depth in a fluid increases?
Pressure increases
Which two forces act on a floating boat?
Weight and upthrust
Which piece of equipment is used to measure mass?
A balance
Which piece of equipment can be used to measure the volume of an irregular object using water displacement?
A Eureka/displacement can
Why does cool fluid sink?
It becomes more dense
What is the equation for pressure?
Pressure = force ÷ area
What may happen if the weight of a boat becomes greater than the upthrust?
The boat will sink
What happens to the density of a gas when its temperature increases?
Its density decreases
Why do objects float more easily in salt water than fresh water?
Salt water is more dense
What type of energy is transferred by convection?
Thermal energy / heat
What is the unit of pressure?
Pascal (Pa)
Why can a steel ship float even though steel is denser than water?
Its hollow shape allows it to displace enough water / lowers its overall density
Why does ice float on water?
Ice is less dense than liquid water
When an object floats, what is equal to the weight of the object?
The weight of the displaced water / the upthrust
What happens to particles when they are heated that causes convection currents to form?
They gain energy and spread out
Why is the upward force on an underwater object greater on the bottom than on the top?
Pressure is greater deeper in the fluid