States of Matter

Classifying Matter

States of Matter

Duration: 60 minutes

Notes / Activity

Fill balloon with solid, liquid and gas. (all 3 balloons must look similar)

Ask students to guess if all 3 balloons are the same.

Activities also allow students to understand the different properties of the 3 states. (Reference)

  • 2-PS1-1 Plan and conduct an investigation to describe and classify different kinds of materials by their observable properties. [Clarification Statement: Observations could include color, texture, hardness, and flexibility. Patterns could include the similar properties that different materials share.]

By the end of this lesson, the student should able to:

  • State the three states of matter
  • Classify matter into solid, liquid or gas

matter     solid     liquid    gas    properties

Lesson Plan

Lesson Introduction – Explore 1

Duration: 20 min

  • Paper 
  • Envelope
  • Welcome students to class.
  • Reveal second secret message (prepare message written or printed on paper in envelope) received: Matter exists as solids, liquids and gases.” 


  • Get students into groups of 4 and ask them to discuss what may be some properties that they can use to classify matter as solids, liquids or gases. 


  • Facilitate a class discussion to ensure that the students have some common properties to classify matter. (e.g. A solid is hard; a liquid flows; a gas is invisible.)
  • Get students to recall the items that they have chosen from the Engage activity.


  • Provide a piece of paper for each group and have them draw a table divided into 4 columns; Solids, Liquids, Gasses , I do not know. Ask each group of students to discuss and sort their items into solids, liquids and gases. 

Note: Allow students to sort their items into “I do not know” column if they are not sure which column a particular matter belongs to after their discussion.  


  • Gather the class together and invite the groups to share their examples, how they have sorted the examples into the respective columns and to justify to the class why they have sorted their examples as such. (For example, a pencil is placed in the column “solid” because it is hard.)

Explore 2

Duration: 30 min

Suggested Questions to ask students during or after the activity:

How do you know it is a solid / liquid / gas?

What are solid / liquid / gas?

  • Play the solid, liquid, or gas touching game. 
  • Call out, “(state of matter),” and have students touch different objects around the class.  

For example: Where is a solid? 

Ans: students will touch a chair, table, pen, book 

  • For liquids, they can touch one of the liquid realia objects or their own water bottles.  For gas, they should breathe and waft the air towards their nose in an exaggerated way (demonstrate first).

Explain 1

Duration: 45 min

  • Launch interactive to explain to students about matter. 
  • Have students articulate:
  • Matter has mass and occupies space
  • Matter exists in three states – solid, liquid and gas 
  • Launch an interactive to have students identify the objects and the states of matter. 
  • Elicit from students:

“Give examples of each of the states of matter”

Explain 2

Duration: 60 min

  • Launch an interactive to have students explore the properties about the three states of matter and how they can classify them.