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5th grade · Science · Unit 4 of 9

Physical or Chemical?

Changes that make new things

What your child practices

Telling a physical change from a chemical change, spotting the signs of a new substance, and how making and throwing away everyday products affects the environment.

Alaska content standards learning standard: 5-PS1-4 · mixing substances that react and make new substances

How we explain it

Children can open this short lesson before they practice.

  1. A physical change alters size, shape or state, but no new substance is made.
  2. Melting, crushing, cutting and dissolving are physical changes.
  3. A chemical change makes a new substance, like rusting or burning.
  4. Signs of a chemical change: gas bubbles, a new smell, color change or light and heat.

Example: Wood burns and turns to ash and smoke. Physical or chemical change? Ash and smoke are new substances. New substances mean a chemical change. Answer: chemical change

Physical or Chemical? in Alaska

In the Alaska content standards, this is unit 4 of 9 in 5th grade Science, after Changes of State and before Measuring Matter.

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: Alaska Department of Education and Early Development

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Cutting paper into small pieces is a…

    • change that makes a new substance
    • chemical change
    • physical change

  2. Question 2

    Baking soda and vinegar are mixed and fizz. What does this show?

    • A chemical change made a new gas
    • Only a physical change happened
    • Nothing happened

  3. Question 3

    Plastic bags can take hundreds of years to break down. Which action helps reduce this harm?

    • Bury plastic bags in a park
    • Use a new plastic bag every time
    • Reuse cloth bags

  4. Question 4

    A banana peel turns brown. What kind of change is this?

    • Change of state
    • Chemical change
    • Physical change

  5. Question 5

    Ice is melted, then the water is boiled. Which statement is correct?

    • Both are physical changes
    • Melting is chemical and boiling is physical
    • Both are chemical changes

  6. Question 6

    Wax melts near a candle flame, while the wick burns. Why is only the burning a chemical change?

    • Melting makes new gases
    • Burning does not change the wick
    • Burning makes new substances; melting does not

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