Particle Basics
What are the tiny pieces that make up all matter called?
Particles
Name the three states of matter.
Solid, liquid, gas
What happens to Jell-O when it is cooled in the fridge?
It becomes solid/firm because particles slow down.
What happens to mass during a phase change?
It stays the same (conservation of mass).
What scale do we commonly use in Canada to measure temperature?
Celsius (°C)
What happens to particles when matter is heated?
They move faster and spread apart.
What do we call it when a solid turns into a liquid?
Melting
Why does a soccer ball become softer in the winter?
Cooling causes particles inside to contract.
When water freezes into ice, does its volume increase or decrease?
Increase—ice expands.
What temperature does water boil at on the Celsius scale?
100°C
What happens to particles when matter is cooled?
They slow down and move closer together.
What phase change is liquid to gas?
Evaporation
Why do puddles eventually disappear on a warm, sunny day?
Evaporation—particles gain energy and become water vapor.
Why does steam take up much more space than liquid water?
Gas particles move very fast and spread far apart.
Why do engineers add expansion joints to bridges?
To allow materials to expand and contract with temperature changes.
What is the model that explains how particles behave in different states of matter?
The Particle Model of Matter
What phase change is when a gas turns directly into a solid without becoming a liquid?
Deposition
When snow melts into water because the sun is shining, what is happening to the particles?
They gain energy, move faster, and spread apart.
If an ice cube melts into water, why is the total mass unchanged even though the shape and volume change?
Particles rearrange, but none are gained or lost.
Concrete, asphalt, and metal all expand when heated and contract when cooled. What can happen to roads or bridges if engineers ignore this?
Cracks or structural damage
What two things happen to both particle movement and spacing when matter changes from a solid to a gas through sublimation?
The particles speed up a lot and spread very far apart without becoming a liquid.
Q: Dry ice turns directly from a solid into gas when left out at room temperature. What is the name of this process, and why does it happen with dry ice but not with water?
Sublimation—because carbon dioxide skips the liquid state and changes directly to gas at normal temperatures.
Why does a metal lid on a jar loosen when you run hot water over it, even though the glass jar stays the same size?
The metal expands more than the glass when heated, weakening the tight seal.
When a puddle evaporates completely, it seems like the water “disappears.” Using the idea of conservation of mass, explain what actually happens to the water particles.
They spread into the air as water vapor; the mass is still there, just in gas form.
Explain why long concrete sidewalks have small gaps between the slabs, and describe what would happen to the concrete if those gaps were not included during extreme temperature changes.
The gaps allow for thermal expansion; without them the concrete would crack or buckle as it expands in heat and contracts in cold.