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4th grade · Science · Unit 1 of 17

Particles & Mass

Matter has mass and space

What your child practices

Solids, liquids and gases at the particle level, how temperature changes particle speed, and conservation of mass (melting or dissolving doesn't change the total mass), with some adding of grams.

Texas Essential Knowledge and Skills (TEKS) teks student expectation: 4.6(A); 4.6(C) · measuring mass and temperature, and that matter is conserved

How we explain it

Children can open this short lesson before they practice.

  1. All matter is made of tiny particles that are always moving.
  2. Solid particles are packed tight. Liquid particles slide past each other. Gas particles spread out.
  3. When matter melts or freezes in a closed container, its mass stays the same.
  4. Warmer particles move faster and spread out, so the matter expands.

Example: You seal 250 g of ice in a bag and it melts. What is the mass of the water? Nothing got in or out of the sealed bag. Melting changes the state, not the amount of matter. Answer: 250 g

Particles & Mass in Texas

In the Texas Essential Knowledge and Skills (TEKS), this is unit 1 of 17 in 4th grade Science, before Mixtures & Solutions.

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: Texas Education Agency (TEA)

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

    Anything that has mass and takes up space is called…

    🧱
    • light
    • matter
    • energy
    • sound

  2. Question 2

    You push an upside-down empty cup straight down into water. Why does the inside stay mostly dry?

    🥤
    • The water is too cold to go in
    • Water only flows downhill
    • Water can't touch plastic
    • The cup is full of air, and air takes up space

  3. Question 3

    Solid, liquid or gas? Tap an item, then tap its basket.

    Sort into: 🧱 solid · 💧 liquid · 💨 gas

    • 🧊ice cube
    • 🍯maple syrup
    • ♨️steam from a kettle
    • 🌧️rain drops
    • 🪨rock
    • 🎈air in a balloon

  4. Question 4

    Why does a hot-air balloon rise?

    🎈
    • Hot air has no mass at all
    • Clouds pull the balloon upward
    • Heated air spreads out, so it's lighter than the same space of cool air
    • The flame pushes the basket up

  5. Question 5

    Leo stirs 44 g of salt into 190 g of water until it dissolves. What is the mass of the salt water?

    ⚖️

    answer boxg

  6. Question 6

    Ravi seals 646 g of ice in a bag. The ice melts. What is the mass of the water in the bag?

    ⚖️

    answer boxg

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