New Substance, or Not?
A 60-minute Grade 5 lesson on conducting an investigation into whether mixing two substances makes a new one.
New Substance, or Not? is a free 60-minute Grade 5 science lesson plan for Common Core standard 5-PS1-4 — test whether mixing substances makes a new one. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.
- Grade:
- Grade 5
- Length:
- 60 minutes
- Standard:
- 5-PS1-4
Grade 5 · Physical Science
5-PS1-4
Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Objective
Students will be able to decide from evidence whether a mixture produced a new substance.
Students are successful when they can
- Names what would count as evidence of a new substance.
- Tests whether the change can be undone.
- Distinguishes a mixture from a new substance.
What you need
- Sand, salt, vinegar, baking soda, milk, lemon juice, beakers, filter paper
- An evaporating dish and a heat source or a warm windowsill
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up
5 min- Stir salt into water and ask whether a new substance has been made.
- Hold the disagreement without settling it.
Teach — can you get it back?
15 min- Evaporate the salt water. The salt returns unchanged: no new substance.
- Filter sand from water. The sand returns: no new substance.
- Mix vinegar and soda: gas is given off and a solid is left that will not undo.
- List the signs of a new substance: gas produced, a solid formed that cannot be undone, a colour change that will not reverse.
- Do milk and lemon juice and ask which signs appear.
- Say the test: can you recover the originals? If not, look for the signs.
“Can you get the starting materials back?”
Investigate — four pairs
22 min- Groups mix four pairs in the same size beakers and observe for ten minutes.
- They attempt to recover the originals by filtering or evaporating.
- They record which signs of a new substance appeared for each pair.
- They classify all four and justify each classification.
Independent practice
15 min- Students complete the 'New Substance, or Not?' page.
- Check the classification rests on evidence, not on appearance.
Close
3 min- Ask which pair was hardest to classify, and why.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Thinks any change of appearance makes a new substance.
Why: It looks different.
Fix: Salt water looks different from salt and undoes completely.
Thinks dissolving is a chemical change.
Why: The solid vanishes.
Fix: Evaporate it. The solid returns unchanged.
Ignores gas as evidence.
Why: It is invisible.
Fix: Fizzing IS the gas. That is a sign something new formed.
If they are not there yet
- Two pairs rather than four.
- A checklist of signs to tick.
If they finish early
- Find a change with one sign only and argue both ways.
- Design a test for a pair not on the list.
- Explain why baking a cake cannot be undone.
Exit ticket
Salt and water can be separated by evaporating. Vinegar and soda cannot be undone. What does each show?
What to look for: Salt and water is a mixture with no new substance; vinegar and soda made new substances, shown by the gas and the solid left. Judging by appearance means the recovery test needs another run.
Printable practice for 5-PS1-4
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- New Substance, or Not?Sort each change into the right group.
Questions about New Substance, or Not?
How long does the New Substance, or Not? lesson take?
60 minutes, split across 5 timed sections: warm-up 5 min, teach 15 min, investigate 22 min, independent practice 15 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.
Which standard does New Substance, or Not? teach?
5-PS1-4 — 5-PS1-4, Physical Science for Grade 5: “Conduct an investigation to determine whether the mixing of two or more substances results in new substances.” In plain terms, test whether mixing substances makes a new one.
What do I need to teach this lesson?
Sand, salt, vinegar, baking soda, milk, lemon juice, beakers, filter paper, an evaporating dish and a heat source or a warm windowsill and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.
What mistakes should I expect in this lesson?
Three, each a reasoning error rather than carelessness: thinks any change of appearance makes a new substance; thinks dissolving is a chemical change and ignores gas as evidence. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.
How do I know whether the lesson worked?
The exit ticket asks: “Salt and water can be separated by evaporating. Vinegar and soda cannot be undone. What does each show?.” Salt and water is a mixture with no new substance; vinegar and soda made new substances, shown by the gas and the solid left. Judging by appearance means the recovery test needs another run. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.
Is there a worksheet to go with New Substance, or Not??
Yes — 1 printable 5-PS1-4 worksheet, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.
Is New Substance, or Not? free to use?
Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on 8 September 2026. Please do not resell it or republish it as your own.
Last reviewed 2026-09-08. Aligned to 5-PS1-4 of the Next Generation Science Standards.