🔬 ScienceLevel 1Lesson 35
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Sorting Materials

Lesson preview: the Mini Lesson and Vocabulary are open to everyone. Guided practice, exercises, the parent checklist and the printable PDF worksheet come with full access (free 7-day trial or membership).

Learning Objectives

  • 1Collect everyday objects and physically sort them by observable properties — hard or soft, transparent or opaque, sink or float and record results
  • 2Explain each choice using correct materials vocabulary
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Mini Lesson

You have already learned about classifying objects by properties, the three states of matter, sink and float, and how materials are chosen for their purpose. Today you put it all together — by getting your hands on real objects and sorting them yourself.

Three sorting rounds

  • Round 1 — Hard or Soft: Press each object with your finger. No dent → hard. Dents or squishes → soft. Examples: rock (hard), cotton ball (soft), wooden block (hard), sponge (soft).
  • Round 2 — Transparent or Opaque: Hold the object up to a light source. Can you see light through it? Yes → transparent. No → opaque. Examples: glass jar (transparent), brick (opaque), plastic wrap (transparent), cardboard (opaque).
  • Round 3 — Sink or Float: Place each object in a bowl of water. Floats on top → float. Goes to the bottom → sink. Examples: cork (float), coin (sink), wooden stick (float), pebble (sink).

Key vocabulary to use on your sheet

Sorting everyday items into wood, metal, and plastic binsThree labeled bins along the bottom — wood, metal, plastic — with sample items above and arrows pointing to the correct bin.Sort by MaterialblockspoonbottleWoodfrom treesMetalshiny · hardPlasticlight · bendy
Each object goes to the bin that matches what it is made of.
Hard versus soft materials compared side by sideA two-column compare chart. Left column: hard items (rock, wooden block). Right column: soft items (cotton ball, sponge).Hard vs SoftHardSoftrockwoodfinger press:no dentcottonspongefinger press:dents or squishesSame test, two results — that is classification.
Press each object with one finger — the result tells you which column it belongs in.
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Ask yourself: "Which property is most useful for the job this object does? Why did the designer choose this material?"

Vocabulary
Property
A characteristic of a material you can observe.
Classify
To group objects by a shared property.
Density
How much material is packed into a space (explains sink or float).
Opaque
Light cannot pass through.
Transparent
Light can pass through and you can see through it.
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