States of Matter Playground

Everything around you is made of matter, and matter comes in three main forms.

• Solid – has a fixed shape and fixed volume (like ice or a rock)
• Liquid – takes the shape of its container but keeps its volume (like water or juice)
• Gas – fills all the space available and has no fixed shape or volume (like steam or air)

All matter is made of tiny particles (atoms or molecules) that are always in motion. The hotter something gets, the faster its particles move.

• Solid – particles vibrate in place but stay in a fixed arrangement
• Liquid – particles slide past each other and flow around
• Gas – particles bounce freely in all directions at high speed

Adding or removing heat energy can change the state of matter.

• Melting – solid turns into liquid when heated (ice → water)
• Boiling – liquid turns into gas when heated more (water → steam)
• Freezing – liquid turns into solid when cooled (water → ice)
• Condensation – gas turns into liquid when cooled (steam → water)

Each substance changes state at specific temperatures. Water melts at 0°C and boils at 100°C.

A heating curve is a graph that shows how temperature changes over time as you add heat to a substance.

The temperature rises steadily while the substance stays in one state. But during a state change (melting or boiling), the temperature pauses and stays flat even though you keep adding heat.

That is because the energy goes into breaking the bonds between particles instead of making them move faster. Once the state change is complete, the temperature starts rising again.