ScienceGrade 5ages 10–11
🫗 A sieve is not for salt
A sieve only catches things bigger than its holes, like a whole grain of sand — but dissolved salt has broken into pieces far smaller than any hole, so getting it back requires evaporating the water instead.
Try this lesson freeNo card needed. The first lesson is free.
Download on the App StoreWhat your child learns
- A filter cloth has tiny holes. Whatever is bigger than a hole is caught, whatever is smaller goes through.
- A grain of sand stays a whole grain in the water, and it is bigger than a hole. So it stops.
- Salt that dissolved broke into pieces smaller than any hole. So no sieve can catch it.
- To get the salt back we remove the water instead: it evaporates, and the salt stays at the bottom.
The mistake most kids make here
A sieve also takes dissolved salt out of water.
Try one question
A sieve separates…
Separates
- dissolved salt from water easily
- undissolved sand from water
- light from shadow
Answer
undissolved sand from water — Yes. The grain of sand stays whole and big, so the cloth stops it.
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 what a sieve catches, and how to get dissolved salt out.
How to help at home
A sieve looks like a general-purpose "cleaning" tool, so it's a reasonable guess that it should remove anything unwanted from water, salt included. The fix is comparing something that stays whole in water (sand) with something that dissolves (salt).
Tonight, stir a spoonful of sand into one cup of water and a spoonful of salt into another. Ask your child to look for the sand (it stays visible, whole grains) versus the salt (it seems to disappear).
If your child expects a sieve to catch both, ask what a sieve could actually grab hold of. A sand grain stays a solid lump bigger than a hole in the sieve; dissolved salt has broken into pieces too small for any hole to stop.
A good sign they've got it: they can say a sieve separates undissolved solids like sand from water, but getting dissolved salt back requires evaporating the water so the salt is left behind.
Questions parents ask
- Why does my child think a sieve can filter out dissolved salt?
- Because a sieve is presented as a general tool for "cleaning" or separating things from water, it seems like it should work on anything unwanted, including salt that has dissolved.
- What does a sieve actually separate?
- A sieve catches solids that stay whole and are bigger than its holes, like a grain of sand — it lets water and anything smaller than a hole pass through.
- How do you get dissolved salt out of water, if not with a sieve?
- By evaporating the water. As the water turns to vapor and leaves, the salt — which cannot evaporate the same way — stays behind.
- How does Maya teach this differently from a worksheet?
- Maya asks what a sieve separates and offers dissolved salt as a wrong option alongside undissolved sand, so a child has to reason about size rather than assume a sieve removes anything unwanted.
No card needed. The first lesson is free.
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Sources: Next Generation Science Standards