Mixing and Changing Materials — Answers
Answer sheet with model answers and success criteria for the 2nd Grade states of matter & materials worksheet.
Success TutoringWorksheetsAnswer sheet2nd Grade · Science · States of Matter & MaterialsMixing and Changing Materials — Answers
Part A: How materials change
Read the passage. Then circle the best answer.
We can change the shape of some materials by bending, squashing, stretching or twisting them. Play dough can be squashed. A rubber band can be stretched.
Some materials dissolve when we mix them with water. Sugar and salt dissolve: they seem to disappear, but they are still in the water. Sand does not dissolve.
Heating and cooling can change materials too. Warmth makes ice melt into water. Very cold air in a freezer makes water freeze into ice.
Some changes can be undone. Melted ice can be frozen again. Some changes cannot be undone. A cooked egg can never be raw again.
- Aits shape
- Bwhat it is made of
- Cits smell
- Dnothing
Answer: its shape
Squashing changes the shape. It is still play dough, and you can roll it back into a ball.
- AThe sugar floats on top.
- BThe sugar dissolves and you cannot see it.
- CThe water turns into sugar.
- DThe sugar turns into sand.
Answer: The sugar dissolves and you cannot see it.
Sugar dissolves in water. It breaks into pieces too tiny to see, but it is still there (the water tastes sweet).
- AIt gets bigger.
- BIt freezes.
- CIt melts into water.
- DIt turns into sand.
Answer: It melts into water.
Warmth makes ice melt. The solid ice turns into liquid water.
- Amelting chocolate
- Bfreezing water
- Cfolding paper
- Dcooking an egg
Answer: cooking an egg
A cooked egg can never go back to being a raw egg. The other changes can be undone.
- AThe sand dissolves.
- BThe sand sinks to the bottom.
- CThe water turns to ice.
- DThe sand floats away.
Answer: The sand sinks to the bottom.
Sand does not dissolve in water. When the water is still, the sand sinks to the bottom.
Part B: Match and fill
- stretching a rubber band
- putting water in the freezer
- stirring salt into water
- leaving butter in a warm spot
- it gets soft and melts
- it gets longer
- it dissolves
- it turns into ice
Answer: stretching a rubber band → it gets longer; putting water in the freezer → it turns into ice; stirring salt into water → it dissolves; leaving butter in a warm spot → it gets soft and melts
Answer: melts
Answer: freezes
Also accept: turns.
Part C: True or false?
Write True or False.
Answer: True
Put the water back in the freezer and it turns into ice again. This change can be undone.
Answer: False
Toasting cannot be undone. The toast will never be soft bread again.
Answer: True
You cannot see the sugar, but you can taste it. It is still there.
Answer: False
Squashing only changes its shape. It is still play dough.
Part D: Working scientifically: what dissolves?
You can try this at home with a grown-up. Do not drink the water.
Fill three clear cups with the same amount of tap water. Stir one teaspoon of sugar into the first cup, one teaspoon of salt into the second and one teaspoon of sand into the third. Stir each cup well, wait one minute and look closely.
Answer: Sugar and salt will dissolve. Sand will not.
Answer: The sand sank to the bottom. The water stayed cloudy for a while, then cleared above the sand.
Answer: So it is a fair test: the only thing that changes is what we put in.
Model answer: Sugar and salt dissolve in water. They seemed to disappear, but they were still there. Sand does not dissolve. It sank to the bottom of the cup.
Success criteria:
- Says sugar and salt dissolved
- Says sand did not dissolve
- Uses the word dissolve correctly
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.
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