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Mix and Flow of Matter – 2nd Half Review Sheet
Topic 4 – Flow Rate and Viscosity
1. Viscosity is essentially how thick (or thin) a fluid is. It can be applied to liquids or gases. A
thicker liquid is said to be more
.
2. Some fluids can flow faster than others. The measurement of how fast a fluid flows from
one point to another is called the fluid’s
.
3. A more viscous fluid will have a
have a
flow rate, while a less viscous fluid will
flow rate.
4. The race is on between 4 liquids – rank the order they will finish in. Koolaid, molasses, olive
oil and melted chocolate.
5. When you add heat to a liquid it becomes
viscous and its flow rate
.
6. Another way of describing viscosity is resistance to flow. Why is this true?
.
7. Gases flow more easily than liquids because their
are farther apart.
8. When the particles of a gas are heated up they move
, and this increase the
friction between the particles and the viscosity of the gas is
.
Topic 5 & 6 – Density & Buoyancy
1. Density is
. We can also think of average density which applies when
an object (like a boat or human body) is made up of different materials and “compartments”.
We can calculate average density by taking the total mass of the object and dividing it by the
total volume.
2. Density is calculated using the following equation: d =
We can determine the mass by
.
the object and we can determine the
volume of a regular shaped object by the formula v = length x width x length. We can place
irregular shaped objects into water – its volume will be equal to the amount of water that is
.
3. A block of steel has a greater density than a same sized block of wood because its’
is greater.
4. The tendency for objects to rise or float in a fluid is called
.
Objects can float in a liquid (e.g. a boat) or a gas (e.g. hot air balloon).
5. Buoyant force is the
force that pushes on objects that are submerged in
fluids; it is measured in newtons (N). The downward force on an object is
.
6. When buoyant force is greater than gravity the object floats and when it is less than gravity
the object will sink. When the forces are about the same the object will neither sink nor float
and this is called
.
7. Buoyant force is affected by the density of the fluid, and the force of gravity works together
with the density of an object to determine if it will float. In other words, if an object has a
greater density than the density of the fluid it will sink.
8. A fish can raise its position in the water by
position in the water by
and it can lower its
. Submarines and scuba divers can move up
and down in the water by using the same principles.
9. Salt water is more dense than fresh water because
Because of this it is
.
for us to float or swim in salt water.
10. If steel has a density of 9.0 g/cm3 and salt water has a density of 1.03 g/cm3 a steel ball will
sink. How is it possible that a huge ship made of steel can float?
.
11. Archimedes Principle states that the buoyant force acting on an object equals the weight of
the
displaced by the object.
Topic 7 – Fluid Pressure
1. Pressure is a measure of
acting perpendicular to
.
2. Pressure can be calculate by the following formula:
3. When you stand on the floor you are applying pressure to that area of the floor directly
underneath your feet. If you lie down on the floor you are applying pressure to the area of
the floor under your whole body. In which case is the pressure greater? Explain why?
.
4. Force is measured in newtons (N). Area is often measured in
Therefore the unit for pressure is:
.
. This is also called a pascal (Pa).
5. If we compress a substance into a smaller space its density will
.
6. What happens to the fluid pressure of a gas when it is compressed into a smaller space?
.
7. When an external force is applied to a liquid or a solid it is
from
one particle to the next. But the particles themselves do not move.
8. If a solid or liquid cannot be squeezed into a smaller space it is said to be
.
9. When a gas is compressed it exerts a
back (a counterforce). This is a useful
property of gases because they can be used to cushion shocks. Give 3 or 4 examples of
how humans use a gas as a cushion:
.
.
10. Why does the atmosphere (made of air) stay around the Earth?
.
11. If you climb a high mountain the pressure on your body
and if you dive
deep into pool of water the pressure on your body
. This is because
the pressure inside your body cannot change as quickly as the pressure outside your body.
Why do you sometimes feel a “pop” in your ear?
12. We use a
.
to measure air pressure. As the air pressure
increases it pushes down on a pool of mercury which then causes it to rise up a thin tube.
When the mercury in the tube falls this tells us that the air pressure is
.
13. Pressure likes to be balanced and so fluids (gases and liquids) will flow from an area of
higher pressure to an area of
.
14. When you drink the last bits of juice from a juice box and the sides get “sucked” in, you can
tell that the air pressure inside the box is
than the air pressure
outside the box. When you finish drinking why does the box return to normal?
.
Topic 8 – Fluid Systems
12. We commonly put gases or a mixture of gases and liquids under pressure so they will
behave the way we want. For example, hair spray is a mixture of gas and liquid under
pressure that produces a fine mist when releases. Think of 3 – 4 other examples of
compressed gases or gases and liquids that you or your parents use at home.
.
13. What household hazardous warning label would you expect to see on the containers of the
products you identified above:
.
14. When compressed gas is released from a container the particles are suddenly able to move
. This motion exerts a
which can be used to do
work – carry, push or move objects.
15.
is the study of pressure in liquids. Tools that take advantage of
this are called
. When a force is exerted on a contained
liquid the pressure increases, and when that pressure is then released it can do work – such
as lifting a car off the ground.
16. Hydraulics are used to transport
over large distances. We use pipelines to
transport materials such as water, oil and gas. What are 2 reasons that the traveling fluids
need to be placed under pressure?
17.
.
are similar to hydraulic systems except they are used to transport
gases instead of liquids. These systems depend on compressors to
gas. Then when the gas is released the particles
force or pressure.
the
, move and exert a