Particle theory
These tiny things make up all matter and are always moving.
What are particles?
This term describes how much matter is packed into a certain amount of space.
What is density?
“This property describes how thick or resistant to flow a liquid is — honey has a high amount of it, while water has a low amount.”
What is viscosity?
This type of system uses liquids to transmit force because liquids cannot be compressed
What is a hydraulic system?
This term describes any substance that can flow and take the shape of its container — including both liquids and gases.
What is a fluid?
According to particle theory, when the temperature of a substance increases, the particles do this.
What is move faster and spread apart?
This term describes how much space a given substance/object takes up
What is Volume?
“This term describes how quickly a fluid moves from one place to another — it increases when viscosity decreases.”
What is flow?
Hydraulic systems are powerful because liquids have this property, meaning they cannot be squeezed into a smaller space
What is low compressibility?
This explains why a person sinks in snow with boots but not with snowshoes.
What is decreased pressure due to increased surface area?
This state of matter has particles that are close together but can slide past each other.
What is a liquid?
Which is a unit of density?
What is g/mL?
This term refers to the amount of force distributed over each unit of surface area, and it explains why the same force can have very different effects depending on how spread out it is
What is pressure?
“Pneumatic systems react quickly because gases have this property, allowing them to be squeezed and store energy.
What is high compressibility?
What is a buoyant force?
The upward force a fluid exerts on an object.
This explains why heating a gas increases its pressure: particles do this more often against the container walls.
What is collide more often (or hit the walls more frequently)?
A metal block has a density of 5 g/cm³ and a volume of 10 cm³. This is its mass.
What is 50 g?
This property describes how much the particles of a substance can be squeezed closer together — gases have a high amount of it, while liquids have very little.”
What is compressibility?
Pneumatic systems are less precise than hydraulic ones because gas particles do this when pressure is applied.
What is compress or spread apart?
A sealed gas keeps the same mass while its volume decreases. What happens to its density?
It increases!
This particle‑theory idea explains why warm air rises and cold air sinks.
What is warm air has lower density because its particles spread out?
A liquid has a mass of 80g and a volume of 100mL. What is it's density? (Answer in g/mL)
0.8g/mL
This principle explains why the volume of water pushed aside by an object is equal to the volume of the object itself.
What is water displacement?
Why are liquids difficult to compress?
Their particles are already close together/ tightly packed.
A vacuum cleaner works because the fast‑moving fan inside lowers the number of air particles, creating this difference that pulls air and dust in.
What is a pressure difference?