2nd grade · Science · Unit 1 of 7
Changing Materials
Cut, bend, mix, cook and burn
What your child practices
Ways to change materials: cutting, bending, mixing, warming and cooling keep the same material, while cooking, burning and rusting make something new.
Arizona Academic Standards learning standard: 2.P1U1.1; 2.P4U1.3 · describing materials, and how heat can change them
How we explain it
Children can open this short lesson before they practice.
- Cutting, bending, melting and freezing change size, shape or state. It is still the same material.
- Cooking, burning and rusting make a new material.
- Ask: can it go back the way it was?
Example: Toasting bread: same material or a new one? Toast can't turn back into soft bread. Heat made something new. Answer: a new one
Changing Materials in Arizona
In the Arizona Academic Standards, this is unit 1 of 7 in 2nd grade Science, before Solids & Liquids.
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.
Source: Arizona Department of Education
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
Some plants, like berries, can be crushed and mixed with water to make…
- 🧶dye to color cloth
- 🪟glass
- 🔩metal
🧶 dye to color cloth
Hint: Crushed plants can give their color to water. People use it to dye cloth.
Question 2
What happens to sugar when you stir it into warm water?
🥄- it turns into a rock
- it floats like a boat
- it seems to disappear into the water
it seems to disappear into the water
Hint: Sugar dissolves. It breaks into tiny bits you can't see, but you can still taste it!
Question 3
Why do we cook food?
🍲- cooking turns food into ice
- cooking changes food so it is safe and tasty to eat
- cooking makes food disappear
cooking changes food so it is safe and tasty to eat
Hint: Heat changes food. Many foods are safer and softer after cooking.
Question 4
A chocolate bar melts in a warm car, then cools at home. Is it still chocolate?
🍫- no, it is now bread
- yes, it is still chocolate
- no, it is now plastic
yes, it is still chocolate
Hint: Melting and cooling are physical changes. The chocolate is the same stuff.
Question 5
Which change can you undo?
- 🔥burning a match
- 🍞baking bread
- ✈️folding a paper plane, then unfolding it
✈️ folding a paper plane, then unfolding it
Hint: Folding only changes the shape. You can unfold it again.
Question 6
What happens to a raw egg when you cook it?
- 🐣it turns into a chick
- 💧it melts into water
- 🍳it turns solid and can't turn back
🍳 it turns solid and can't turn back
Hint: Cooking changes an egg for good. That is a chemical change.