The Particle Model
What is matter? [definition]
Anything that has mass and takes up space
During a change of state, temperature:
a) increases
b) stays constant
c) decreases
b) stays constant
What unit is pressure measured in?
Pascals (Pa)
If an object is more dense than the fluid, what will it do?
Sink
In what substance does drag occur?
fluids (air & water)
What happens to particle movement when particles are heated?
Particles move/vibrate faster
Define: anomalous
Something that does not fit a pattern
What is pressure? [definition]
the force acting on an area
What force pushes objects up in a fluid?
Upthrust
What are the two types of drag?
air resistance & water resistance
What is the random movement of particles in fluids called?
Brownian motion
What is it called when a solid turns directly into a gas?
sublimation
What causes pressure in fluids?
Particle collisions
What is an object's force of gravity called?
weight
What happens to drag as speed increases?
Increases
Materials _______ when heated and ______ when cooled
Materials expand when heated and contract when cooled
Why does the volume of a substance increase when it gets warmer?
The particles have more energy and move apart
Why does pressure increase when we go deeper underwater/underground
More particles above pushing down
What is the unit for density?
kg/m3 OR g/cm3
What happens when drag equals forward force?
The object moves at a constant speed
Which is correct?
a) density = mass × volume
b) density = volume ÷ mass
c) density = mass ÷ volume
c) density = mass ÷ volume
Why is water's behaviour anomalous when it's a solid?
Water expands as a solid (does not compress)
Name one way to increase pressure in a fluid
Increase temperature / increase particles / decrease volume
Name on factor affecting upthrust?
Fluid density / displaced volume
Name two ways we can reduce drag
1. Having a smooth shape
2. Keep the front area as small as possible