States and Changes of Matter

Three States of Matter

• Solid: Solids have a definite shape and volume. Their particles are packed tightly together, vibrating in place but not moving around freely. Examples include ice, wood, and rocks.
• Liquid: Liquids have a definite volume but take the shape of their container. Their particles are close together but can move past each other. Examples include water, juice, and milk.
• Gas: Gases have neither a definite shape nor a definite volume. Their particles are far apart and move freely in all directions. Examples include air, oxygen, and helium.

Physical Changes in Matter

• Definition: Physical changes alter the form or appearance of matter but do not change its chemical composition. The substance remains the same substance.
• Examples:
  • Melting ice (water changes from solid to liquid)
  • Boiling water (water changes from liquid to gas)
  • Dissolving sugar in water (sugar dissolves in water but is still sugar)
  • Crushing a rock (rock changes shape but is still rock)
  • Cutting paper (paper changes shape but is still paper)
  • Bending a metal rod (metal changes shape but is still the same metal)
• Key feature: No new substances are formed during a physical change.

Chemical Changes in Matter

• Definition: Chemical changes occur when a substance is transformed into a different substance with different properties. The original substance is changed into a new substance.
• Examples:
  • Burning wood (wood transforms to ash and smoke with different substances)
  • Rusting iron (iron combines with oxygen in the air and forms a new substance called iron oxide —making it rust)
  • Baking a cake (ingredients combine to create a new substance in a cake)
  • Digesting food in your body (your food changes into different substances as it's broken down).
  • Frying an egg (protein reacts chemically and changes colours and form)
• Key features:
  • New substances are formed in a chemical change (e.g. iron is transformed into iron oxide when it rusts).
  • Energy is often released or absorbed during the change (like heat, light, or sound).
  • Physical properties (like color, texture, or state of matter) change noticeably.
• Important Notes for Grade 5: Chemical changes are often noticeable by seeing bubbles, producing heat, or a noticeable smell. Different substances are now present than in the start, although not always easy to see.

Explore the three states of matter: solid, liquid, and gas, along with the definition and examples of physical changes. This quiz will test your understanding of how substances change form while retaining their chemical identity. Learn about the properties and behaviors of different states of matter through engaging questions.