Science · Grade 2 · Properties of Liquids and Solids · Term 2

Identifying Solids

Students will observe and describe the properties of various solid objects, focusing on shape, texture, and hardness.

• Ontario Curriculum Expectations
• 2-PS1-1

About This Topic

States of Matter introduces students to the observable properties of solids and liquids. In the Ontario Grade 2 curriculum, students learn to distinguish between these states by exploring how they occupy space and behave when moved or poured. This unit encourages students to use their senses to describe textures, shapes, and the way materials flow. It also touches on the safety aspects of handling different substances, which is a key life skill.

Students investigate why some solids, like sand, can seem to act like liquids, and why liquids always take the shape of their container. This topic is perfectly suited for station rotations and hands-on testing. When students can physically manipulate materials, stacking blocks versus pouring water, they build a concrete understanding of physical properties. Active exploration allows them to test their own hypotheses about how matter behaves in the real world.

Key Questions

1. Compare the properties of a rock and a wooden block.
2. Explain how we can classify solids based on their observable characteristics.
3. Predict if an unknown object is a solid based on its shape and feel.

Learning Objectives

• Classify solid objects based on observable properties such as shape, texture, and hardness.
• Compare and contrast the properties of two different solid objects, like a rock and a wooden block.
• Describe the characteristics of a solid object, predicting if an unknown object is a solid based on its shape and feel.
• Identify at least three observable properties of a solid object.

Before You Start

Using the Senses to Observe

Why: Students need to be able to use their senses of sight and touch to gather information about objects.

Basic Object Properties

Why: Familiarity with basic descriptive words for objects, such as color and size, will help students learn new properties like shape and texture.

Key Vocabulary

Solid	A state of matter that has a definite shape and a definite volume. Solids do not flow easily.
Shape	The outline or form of an object. Solids keep their shape.
Texture	How something feels when you touch it, such as rough, smooth, bumpy, or soft.
Hardness	How resistant a solid is to being scratched or dented. Some solids are hard, and some are soft.

Watch Out for These Misconceptions

Common Misconception

Powders and sand are liquids because they can be poured.

What to Teach Instead

Students often confuse the behavior of a bulk material with its state. Use magnifying glasses so students can see that sand is made of tiny, hard solids that don't change shape themselves, unlike water droplets.

Common Misconception

Liquids always stay the same volume.

What to Teach Instead

While true, students often think a tall, skinny glass holds more than a short, wide one. Use a 'conservation of volume' demonstration where students pour the same amount of liquid into different shaped containers to see it is still the same amount.

Active Learning Ideas

Stations Rotation: The Property Lab

Set up stations with different materials (sponge, water, rock, oil, sand). Students rotate through, performing tests like 'Can I stack it?' or 'Does it change shape in a bowl?' and recording their findings in a simple chart.

45 min·Small Groups

Think-Pair-Share: The Sand Mystery

Show students a jar of sand being poured. Ask: 'Is this a liquid or a solid?' Students think individually, pair up to discuss based on their observations of individual grains, and then share their conclusion with the class.

15 min·Pairs

Inquiry Circle: Liquid Races

In small groups, students predict which liquid (water, maple syrup, or dish soap) will flow down a tilted tray the fastest. They conduct the race, measure the results, and discuss how 'thickness' or viscosity changes a liquid's behavior.

30 min·Small Groups

Real-World Connections

• Construction workers classify building materials like bricks, wood, and concrete based on their hardness and texture to determine their suitability for different parts of a building.
• Toy designers consider the shape, texture, and hardness of materials when creating toys for young children, ensuring they are safe and engaging to handle.
• Geologists examine the shape and texture of rocks to classify them and understand how they were formed, helping us learn about Earth's history.

Assessment Ideas

Exit Ticket

Give each student a small bag with two different solid objects (e.g., a smooth stone and a rough piece of wood). Ask them to write one sentence comparing their shapes and one sentence describing their textures.

Quick Check

Hold up an everyday solid object, like a pencil or an eraser. Ask students to raise their hands if they can identify its shape and describe its texture. Call on a few students to share their observations.

Discussion Prompt

Present students with a picture of an unknown object. Ask: 'Based on its appearance, what do you predict its shape is? What might its texture feel like? How can we tell if it is a solid?' Encourage students to use the vocabulary words.

Frequently Asked Questions

What safety symbols should Grade 2 students know?

Students should be introduced to basic HHPS (Hazardous Household Product Symbols) like 'Caution,' 'Danger,' 'Flammable,' and 'Poison.' Learning to recognize these on common household cleaners is a practical application of the matter unit.

How do I explain 'gas' to Grade 2s if the unit focuses on solids and liquids?

While the focus is on solids and liquids, you can introduce gas as 'invisible matter' that fills balloons or bubbles. This sets the stage for Grade 5 science while keeping the current focus on what they can easily see and touch.

What are the best hands-on strategies for teaching states of matter?

Station rotations are highly effective because they allow students to interact with a wide variety of materials in a short time. Providing 'mystery bags' where students must feel an object and describe its properties without looking also builds descriptive vocabulary and scientific reasoning.

Why does maple syrup flow differently than water?

This is a great chance to talk about viscosity. Explain that some liquids are 'thicker' and their parts stick together more, making them move slower. This is a perfect connection to a famous Canadian product!