Lesson Notes By Weeks and Term v5 - Grade 5

Lesson Video

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Performance objectives

• Define 'mixture' and 'solution'.
• Identify common mixtures and solutions at home.
• Describe the process of dissolving.
• Tell the difference between soluble and insoluble substances.
• Learn how to separate a simple mixture.

Lesson summary

Welcome, Grade 5 learners! This week, we're diving into the fascinating world of matter and exploring how different materials can be mixed together. We will learn about mixtures and solutions, understanding the difference between them. This is important because mixtures and solutions are everywhere around us – from the air we breathe to the food we eat. Understanding these concepts will help you understand the world around you and even help you in the kitchen! For example, when you help your family prepare mageu or mix sugar into your tea, you are working with mixtures and solutions! Understanding how these things work makes you a better observer and problem-solver.

Lesson notes

What is Matter? Matter is anything that takes up space and has mass. Everything around you – the air, your desk, your books, even you – is made of matter. What is a Mixture? A mixture is a combination of two or more substances that are physically combined, but not chemically combined. This means that the substances in a mixture retain their individual properties. You can usually see the different parts of a mixture.

Examples of Mixtures: Trail mix: A combination of nuts, seeds, dried fruit, and sometimes chocolate. You can clearly see each of these components.

Soil: A complex mixture of sand, silt, clay, organic matter, and rocks. You can often see small pieces of different materials in the soil.

Gravel: A mixture of different sized rocks and pebbles. What is a Solution? A solution is a special type of mixture where one substance (the solute) dissolves evenly into another substance (the solvent). When a solute dissolves in a solvent, it seems to disappear, and you can no longer see the separate substances.

Solute: The substance that dissolves.

Examples: sugar, salt, juice powder.

Solvent: The substance that does the dissolving.

Examples: water, vinegar.

Examples of Solutions: Sugar water: Sugar dissolves completely in water, creating a clear solution.

Salt water: Salt dissolves completely in water, creating a clear solution.

Vinegar: A solution of acetic acid (the solute) in water (the solvent).

Dissolving: How Does it Work? Dissolving is the process where the particles of the solute spread evenly throughout the solvent. Imagine tiny sugar particles getting surrounded by water particles and spreading out until they are evenly distributed.

Important Terms: Soluble: A substance that can dissolve in a particular solvent. Sugar is soluble in water.

Insoluble: A substance that cannot dissolve in a particular solvent. Sand is insoluble in water. Separating Mixtures Because the substances in a mixture are not chemically combined, they can be separated using physical methods.

Here are a few examples: Sieving: Using a sieve (a mesh screen) to separate materials of different sizes. For example, separating stones from sand.

Filtration: Using a filter to separate solid particles from a liquid. For example, using a coffee filter to separate coffee grounds from brewed coffee.

Evaporation: Heating a solution to evaporate the solvent, leaving the solute behind. For example, evaporating saltwater to obtain salt.

Magnetism: Using a magnet to separate magnetic materials from non-magnetic materials. For example, separating iron filings from sand.

Worked example

Example 1: You mix sand and small pebbles together. Is this a mixture or a solution? Why?

Answer: This is a mixture. You can still see the individual grains of sand and the pebbles. They have not dissolved into each other.

Example 2: You stir cooldrink powder into water. After stirring, the powder disappears, and the water turns a different colour and tastes sweet. Is this a mixture or a solution? Why?

Answer: This is a solution. The cooldrink powder (solute) has dissolved completely into the water (solvent). You can no longer see the individual powder particles.

Example 3: You have a mixture of iron filings and sand. How can you separate these materials?

Answer: You can use a magnet. The iron filings are magnetic and will be attracted to the magnet, allowing you to separate them from the non-magnetic sand.

Guided Practice (With Solutions)

Question 1: Classify the following as either a mixture or a solution:

a) Salad

b) Lemonade

c) Air

d) Gravel

Solution:

a)

Mixture: You can see the different vegetables in the salad.

b)

Solution: The lemon juice and sugar dissolve completely in the water.

c)

Solution: Although you can't see it, air is a solution of different gasses (oxygen, nitrogen, etc.).

d)

Mixture: You can see the individual rocks that make up the gravel.

Question 2: Sarah adds a teaspoon of sugar to a glass of water and stirs it. The sugar disappears.

a) What is the solute in this situation?

b) What is the solvent in this situation?

c) What happens to the sugar particles when they dissolve?