Natural Sciences and Technology Grade 6-A - Thunderbolt Kids
Natural Sciences and Technology Grade 6-A - Thunderbolt Kids Natural Sciences and Technology Grade 6-A - Thunderbolt Kids
3 Solutions as special mixtures NEW WORDS • solution • solvent • solute 134 KEY QUESTIONS • When is amixture also asolution? • Do all substances dissolve in water? • Is therealimit to how much of a substance can be dissolved in a given amount of water? • How can the components of asolution be separated? 3.1 Solutions In the last chapter we looked at mixtures. We are now going to look at a special case of mixtures, which are called solutions. When is amixture also asolution? When two substances are mixed it will be possible to still see each substance in the mixture. Is sugar and sand amixture? Yes! A solution is aspecial type of mixture. What makes a solution so special? When is amixture also asolution? Often, the best way to answer a question is to ask it in adierent way: When is amixture NOT a solution? In the next activity we are going to make a few mixtures and then decide which of them are solutions, and which of them are not. That should help us find the answer to the question: When is a mixture also asolution?
ACTIVITY: When is amixture also asolution? In this activity we are going to mix substances with water to see which ones make solutions. How do you think will we know when asubstance has made a solution with the water? MATERIALS: • small quantities of the following substances: – sugar – salt – sand – oil – vinegar – flour – copper sulfate • tap water • clean yoghurt tubs (small) • plastic spoons for scooping and stirring INSTRUCTIONS: 1. Half-fill ayoghurt cup with tap water. 2. Place one small scoop of sugar in the water and stir it well. 3. Look at the mixture and discuss what it looks like. 4. At the top of the table below, a few possible observations are given. Choose the one that is the best description for what you observed, by making across in the matching column. (You may also choose more than one column.) The first substance (sugar) has been filled in to show you what you should do. Chapter 3. Solutions as special mixtures 135
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ACTIVITY: When is amixture also asolution?<br />
In this activity we are going to mix substances with water to see<br />
which ones make solutions.<br />
How do you think will we know when asubstance has made a<br />
solution with the water?<br />
MATERIALS:<br />
• small quantities of the following substances:<br />
– sugar<br />
– salt<br />
– s<strong>and</strong><br />
– oil<br />
– vinegar<br />
– flour<br />
– copper sulfate<br />
• tap water<br />
• clean yoghurt tubs (small)<br />
• plastic spoons for scooping <strong>and</strong> stirring<br />
INSTRUCTIONS:<br />
1. Half-fill ayoghurt cup with tap water.<br />
2. Place one small scoop of sugar in the water <strong>and</strong> stir it well.<br />
3. Look at the mixture <strong>and</strong> discuss what it looks like.<br />
4. At the top of the table below, a few possible observations are<br />
given. Choose the one that is the best description for what<br />
you observed, by making across in the matching column.<br />
(You may also choose more than one column.) The first<br />
substance (sugar) has been filled in to show you what you<br />
should do.<br />
Chapter 3. Solutions as special mixtures<br />
135
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