Lesson 138: Solid, liquid, gas basics

🔬 SCIENCE (40 Lessons) • 🟡 C. Materials and Matter

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Objective

I can tell the difference between a solid, a liquid, and a gas. I can give simple examples like ice, water, and air and say how each one behaves.

Materials

Mini-lesson — Solid, liquid, gas

Many things around us are made of matter. Matter can be a solid, a liquid, or a gas.

Solids

  • Solids keep their shape.
  • A block of ice, a toy, and a book are solids.
  • You can hold a solid and it does not flow away.

Liquids

  • Liquids can be poured.
  • They do not keep their own shape. They take the shape of the cup or bottle they are in.
  • Water, milk, and juice are liquids.

Gases

  • Gases often look invisible to us.
  • The air we breathe is a gas.
  • Gases can spread out and fill space, like air inside a balloon.

One example: water

  • Ice is solid water.
  • Water in a cup is a liquid.
  • Steam or water vapour is water as a gas in the air.

We can use simple questions to help: Does it keep its shape? Can it be poured? Does it feel like air? This helps us decide if it is a solid, a liquid, or a gas.

Picture strip: Ice, water, and air

Ice — solid

Water — liquid

Balloon — gas inside

Guided Practice — Solid or liquid or gas?

You will look at ice, water, and air in a balloon. Use simple words to say if each one is a solid, a liquid, or a gas.

  1. Look at the ice: Touch it gently if it is safe. Does it keep its shape when you pick it up? Say, "Ice is a solid."
  2. Look at the water: Watch it in the cup. Can it be poured into another cup? Say, "Water is a liquid."
  3. Look at the balloon: Gently press the balloon. You cannot see the air, but it is inside. Say, "Air is a gas."
  4. Draw three pictures: On your paper draw ice, water in a cup, and a balloon. Under each picture write "solid", "liquid", or "gas".
  5. Use the tracing pad: Choose words like solid, liquid, gas, ice, or water from the dropdown and trace them slowly. Say the word as you write.
  6. Finish with a sentence: Write one sentence such as "Ice is a solid that keeps its shape" or "Water is a liquid that can be poured".
Tracing Pad
Tracing snapshot for print
Tip: As you trace the words, point to things in the room and say if they are solid, liquid, or gas.

Practice 1 — Sort solids, liquids, and gases

Sort everyday examples into solid, liquid, or gas.

  1. Draw three boxes on your paper and label them: "Solids", "Liquids", and "Gases".
  2. Think of things you know, such as: ball, book, chair, water, milk, juice, air in a balloon, steam from a kettle.
  3. Write or draw each thing in the box you think it belongs in. For example, "ball" goes in "Solids", "water" goes in "Liquids".
  4. Talk with an adult about any you are unsure of. Use the questions: "Does it keep its shape?" and "Can it be poured?" to help you decide.

Practice 2 — What can water be?

Think about how water can be a solid, a liquid, or a gas.

Practice 3 — Solid, liquid, gas story

Tell a short story that includes a solid, a liquid, and a gas.

  1. Choose one solid (for example, ice lolly or ball), one liquid (for example, juice or water), and one gas (for example, air in a balloon).
  2. Draw a simple picture that shows all three together.
  3. Write (or say) one or two sentences, such as: "I drink liquid juice, hold a solid ball, and the balloon is full of gas."
  4. Point to each thing in your picture and tell someone if it is a solid, a liquid, or a gas.

Quick Check — Solid, liquid, gas basics

Answer each question about solids, liquids, and gases. Use the ideas of keeping shape, being poured, and filling space.

1) Which word names one of the three basic states of matter?

The three basic states we are learning are solid, liquid, and gas.

2) Which list shows all three states?

Solid, liquid, and gas are the three states we are studying.

3) Which sentence about a solid is true?

Solids keep their own shape unless we cut or break them.

4) Which is a good example of a solid?

A toy block is a solid that keeps its shape.

5) Which sentence about a liquid is true?

Liquids change shape to match the cup or bottle they are in.

6) Which is a good example of a liquid?

Water in a glass is a liquid that can be poured.

7) Which sentence about a gas is true?

Gases spread out to fill the space available to them.

8) Which is a good example of a gas?

The air inside a balloon is a gas that fills the balloon.

9) Which sentence about ice, water, and steam is true?

Ice, liquid water, and steam are all water in different states.

10) Which question helps you decide if something is a solid?

Solids keep their shape even when we move them.

11) Which question helps you decide if something is a liquid?

Liquids can be poured and change shape to fit their container.

12) Which question helps you think about a gas?

Air is a gas we often cannot see, but it is still there.

13) A child says, "Juice is a liquid." Why is this a good idea?

Liquids like juice can be poured and take the shape of their container.

14) Why do we learn about solids, liquids, and gases?

Knowing the states of matter helps us understand the world around us.

15) Which sentence shows a good understanding of solid, liquid, gas?

This sentence matches each example to the correct state of matter.

Assessment (parent/teacher)

Exit ticket (student)

Next time I will practise…

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