Some changes are just for looks — like melting ice. Others make a brand-new substance — like burning wood. Learn to tell them apart!
⚖️Two Kinds of Change
🧊PHYSICAL CHANGE
The form changes, but it's still the same stuff. Often easy to reverse.
🫠 melting · ❄️ freezing · ✂️ ripping paper
🥄 dissolving sugar · 🪟 breaking glass
✅ Same substance — just a new shape or state
🔥CHEMICAL CHANGE
A new substance is made. The atoms rearrange — usually hard to reverse.
🔥 burning · 🦴 rusting · 🍰 baking a cake
🍎 fruit rotting · 🎆 fireworks · 🧪 reacting
⚠️ New substance — you can't get the old one back
🕵️Signs of a Chemical Change
Color change
An unexpected new color appears
Gas / bubbles
Fizzing or new bubbles form
Heat or light
It gets hot, glows, or burns
Hard to reverse
You can't easily un-do it
⚓Float, Sink & Dissolve — Density
🌊 Does it float or sink?
Less dense than water → it floats 🟡
More dense than water → it sinks ⬛
Density = mass ÷ volume — how tightly matter is packed
Solubility = whether one thing can dissolve in another (sugar in water!)
🔑Key Terms
🧊Physical ChangeThe form changes but the substance stays the same (melting, ripping).
🔥Chemical ChangeA brand-new substance is created (rusting, burning).
⚖️DensityHow tightly matter is packed (mass ÷ volume) — sets float or sink.
🥄SolubilityThe ability of one substance to dissolve in another.
🧱Mass & VolumeMass = amount of matter; Volume = the space it takes up.
♻️Conservation of MassMass is never made or lost in a change — only rearranged.
⭐Remember: a physical change just changes how matter looks, but a chemical change makes a brand-new substance — and either way, no mass is ever created or destroyed!
✏️ ClickClass Anchor Chart · Physical & Chemical Changes