ScienceGrade 7ages 12–13
🧂 Mixture versus one material
Stirring salt into water looks like it makes something brand new, but the salt and water are both still there, keeping their own properties — which is exactly what makes a mixture different from a true element and separable again.
Try this lesson freeNo card needed. The first lesson is free.
Download on the App StoreWhat your child learns
- In a mixture each material goes on being what it was. Iron stays magnetic, salt stays soluble.
- It is exactly the surviving properties that make separating possible: a magnet pulls only the iron.
- An element is one kind of stuff, like iron or gold, with no two things inside it to pull apart.
- So mixing does not invent a new material. It is neighbours, and the arrangement can be undone.
The mistake most kids make here
Mixing always makes a new element you cannot separate.
Try one question
Salty water is…
The salty water
- a new metal
- a mixture you can often separate
- a living cell
Answer
a mixture you can often separate — Yes. Both are in there keeping their own nature, so there is a way back.
How Maya teaches it
Your child tells Maya what they did in class. She teaches this topic at her desk, asks questions with tappable answers, and when the answer is wrong she explains why that answer was tempting instead of saying “try again”. She remembers what did not land and comes back to it.
Your child has it when they can: Say how a mixture differs from one material.
How to help at home
When two things combine and the result looks uniform, like salty water, it's easy to assume something entirely new and unbreakable has formed. The giveaway that it hasn't is that each ingredient's own properties are still detectable if you look for them.
Tonight, dissolve a spoonful of salt in a glass of water and taste a drop (or just discuss it) — the saltiness is still there, meaning the salt never disappeared or turned into something else, it's just spread through the water.
If your child says mixing always makes something new and unseparable, ask 'if we let this salty water evaporate, what do you think will be left in the glass?' Salt crystals reappearing shows both ingredients were there the whole time.
A good sign they've got it: they can explain that a mixture keeps its ingredients' original properties and can often be separated back out, while a true element is one single kind of substance with nothing else mixed in.
Questions parents ask
- Why does my child think mixing always creates a brand-new, unseparable substance?
- A uniform-looking mixture like salty water can seem like something entirely new formed. Letting salty water evaporate and seeing the salt crystals reappear shows both original substances were present the whole time and can be separated.
- What's the actual difference between a mixture and an element?
- In a mixture, each substance keeps its own properties and the parts can usually be separated again; an element is one single kind of substance, like iron or gold, with nothing else combined into it to separate out.
- How can you tell if something is a mixture just by looking at it?
- You often can't tell by looking alone — salty water looks uniform — but testing for the original properties (like tasting the salt, or using a magnet to pull out iron) reveals whether the ingredients are still separately present.
- How does Maya teach this differently from a chemistry worksheet?
- Maya asks what salty water actually is and offers real options, like 'a new metal' versus 'a mixture you can often separate,' so the child has to reason through the evidence rather than memorize a category label.
No card needed. The first lesson is free.
Download on the App StoreMore Science lessons
- Atom and brickGrade 7
- Plant and lightGrade 7
- DensityGrade 7
- Who eats whomGrade 6
- A cell is a unit of lifeGrade 6
- A habitatGrade 6
- A simple machineGrade 6
- Not goneGrade 6
Sources: Next Generation Science Standards