5th grade · Science · Unit 4 of 12
Solutions & Mixtures
Dissolving and separating mixtures
What your child practices
Solutions versus mechanical mixtures, solutes and solvents, what affects dissolving, and ways to separate mixtures (filtering, evaporation, magnets, chromatography).
Alabama Course of Study content standard: 5.2; 5.4 · identifying materials by their properties, and testing whether mixing makes a new substance
How we explain it
Children can open this short lesson before they practice.
- In a solution, one substance dissolves into another, like salt in water.
- A filter separates things that don't dissolve, like sand from water.
- Dissolved salt is too tiny for a filter, so heat the water to evaporate it. The salt stays behind.
- Cool the vapor and it condenses back into pure water.
Example: How could you get the salt back out of salt water? Salt is dissolved, so a filter won't catch it. Heat the water until it evaporates. The salt is left behind. Answer: evaporate the water
Solutions & Mixtures in Alabama
In the Alabama Course of Study, this is unit 4 of 12 in 5th grade Science, after Measuring Matter and before Changes of State.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
Kenji has a dry mix of iron filings, sand and salt. Put his separation steps in order.
- 🧲Run a magnet through the dry mix to pull out the iron
- ☕Pour it through a filter to catch the sand
- ☀️Let the water evaporate to leave the salt
- 🥄Add water and stir until the salt dissolves
Run a magnet through the dry mix to pull out the iron → Add water and stir until the salt dissolves → Pour it through a filter to catch the sand → Let the water evaporate to leave the salt
Hint: Use the magnet while the mix is still dry. Then dissolve the salt, filter out the sand, and evaporate the water to get the salt back.
Question 2
A sieve separates the parts of a mixture by their…
- color
- size
- magnetism
- temperature
size
Hint: Small pieces fall through the holes in a sieve; bigger pieces stay on top.
Question 3
Which tool would separate iron filings from sand?
🧲- a measuring cup
- a thermometer
- a magnet
- a filter
a magnet
Hint: Iron is attracted to magnets. Sand is not.
Question 4
A dot of black marker on wet paper spreads out into several colors. What is this separation method called?
🖊️- filtration
- sieving
- chromatography
- evaporation
chromatography
Hint: In chromatography, water carries each ink color a different distance up the paper, separating the mixture.
Question 5
Soluble or insoluble in water? Tap an item, then tap its basket.
Sort into: 💧 soluble · 🚫 insoluble
- 🧃drink crystals
- 🏖️sand
- 🧂table salt
- 🍯honey
- 🧲iron filings
- 🪨pebbles
💧 soluble: drink crystals, table salt, honey · 🚫 insoluble: sand, iron filings, pebbles
Hint: A soluble substance dissolves and seems to disappear in water. An insoluble one stays visible, sinks or floats.
Question 6
Which substance will dissolve in water?
- pebbles
- sugar
- sand
- cooking oil
sugar
Hint: Sugar is soluble: it dissolves and spreads evenly through the water.