NATURAL SCIENCES AND TECHNOLOGY TERM Contents

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1 NATURAL SCIENCES AND TECHNOLOGY TERM Contents Unit 1: Arrangements of Particles: Solids, Liquids and Gases... 6 Lesson Solids... 6 Liquids... 6 Gas... 6 Activity Questions... 7 Unit 2- Mixture: Mixtures of Materials... 7 Lesson Mixtures... 7 Examples of Mixtures... 7 Separating Mixtures... 8 Activity Investigate methods to separate a mixture... 9 GM 2018

2 1 Unit 3 Solutions as Special Mixtures: Solutions Lesson Solutions Dissolving a solid Activity 3 Mixing substances Unit 4- Solutions as Special Mixtures: Soluble Substances Lesson Dissolving a solid: Solutes and Solvent The making of Sea Salt Discussion: Activity Methods of separating salt from water Unit 5 Solutions as Special Mixtures: Saturated Solutions Lesson Saturated Solutions A natural example of a saturated solution: Unit 6- Solutions as Special Mixtures: Insoluble Substances Lesson Insoluble Substances Insoluble Substances as Water Pollution Unit 7- Dissolving: Rates of Dissolving Lesson Rates of Dissolving There are three factors that affect the rate of dissolving: Activity Investigate the rate of dissolving and grain size Unit 8- Mixtures and Water Resources: Water Pollution Lesson Water: A precious resource in South Africa Water Pollution Insoluble Substances Oil Pollution Preventing Water Pollution Soluble Substances... 17

3 2 Impact of Fertilisers on Rivers Preventing Water Pollution: Living Germs Cycle of Infection: Activity Activity Unit 9 Mixtures and Water Resources: Importance of Wetlands What is a Wetland? How Wetlands control floods How Wetlands clean polluted water Edith Stephens Wetland Park Cape Flats Activity Unit 10 Process to Purify Water: Clean Water Lesson Animals and water Plants and Water The Importance of clean water How a water treatment facility works Activity Activity Unit 13 Skills Focus: How to Follow Steps of a Scientific Investigation... 23

4 3 Natural Science: The Scientific Method Use this format to follow the scientific method for your experiments Question to investigate What will my experiment answer? Hypothesis What do I think the results of this experiment will be? Materials What do I need to conduct this experiment? Method How will I conduct this experiment? Step 1 Step 2 Step 3 Step 4 Step 5 Results and conclusions What are the results of my experiment? Was my hypothesis correct? [ ] Yes [ ] No Discussion How can the results of my experiment be used? What other questions does my investigation raise?

5 4 Technology: The design process Use this format to follow the design process for your technology projects Investigate What must my product do? Design and plan Specifications: What are the specifications? (E.g. instructions, design brief) Constraints: What are the constraints? (E.g. materials, time, tools) Materials: What materials am I going to use? Equipment: What tools do I have? What tools will I need? Final drawing (What will my product look like?) How am I going to make my product? Step 1 Step 2 Step 3 Evaluate Does my product work properly? [ ] Yes [ ] No Does my product look like my drawing? [ ] Yes [ ] No How can I make my product better?

6 5 Natural Sciences & Technology Grade 6 Term 2 Strand 2 Natural Sciences: Matter and Materials Technology: Processing Introduction Solids, liquids and gases are the three main states of matter. Materials and substances are made of matter. Matter is made of particles. The way the particles are arranged makes the matter a solid, a liquid or a gas. It is also possible to mix different types of particles together in their different states. Matter and Material Processing Solids, liquids and gases Mixtures Solutions as special mixtures Dissolving Mixtures and water resources Process to purify water Arrangement of particles Mixtures of materials Solutions Rates of Dissolving Water pollution Clean water Soluble substances Importance of wetlands Insoluble Substances

7 6 Unit 1: Arrangements of Particles: Solids, Liquids and Gases Lesson 1 Scientists use the word matter to talk about what everything around you is made of. Even you as a person is made of matter. All materials and substances are made of matter. Matter is made of very small particles. How small is the particle? - Hold a piece of paper in your hand. - Hold it level with your eyes. - Notice that the paper is very thin - Paper is made of millions and millions of particles - A piece of paper is particles thick. A particle is the smallest part of a substance Particles move. Particles move all the time. Sometimes they move slowly, sometimes they move fast. The speed and distance they move in determines if the material or substance is a solid, a liquid or a gas. The particles in solids, liquids and gases are all arranged differently. Solids When matter is solid it has a fixed shape. The particles of solids are packed closely together. There is very little space between the particles. The particles vibrate or move in one place. A five rand coin is a solid object. It is made of metal. Can you push your finger through a coin? No, because the particles are packed so closely together you cannot push them apart. Liquids Matter in the liquid state is able to flow. The substance will take on the shape of the container it is in. The particles are packed close together, but they have no fixed shape. There are small spaces between the particles. The particles can move around each other. Gas When matter is in the gas state it fills the available space around it. The particles in gas are far apart from each other and move fast. There is a lot of space between the particles.

8 The particles move in all directions. Air is a gas that fills the room, a balloon or even a whole atmosphere. 7 Summary Matter is made of particles which are moving all the time. There are spaces between the particles of matter. Particles move faster when we add heat to them. In solids, the particles of matter are held close together and move slowly. In liquids, the particles are further apart and can move faster. In gases, the particles are far apart and move very fast and freely. Activity 1 Questions Identify the type of matter represented by: 1. Standing close together. 2. Spread out holding hands. 3. Running around each other. ==================================================================== Lesson 2 Unit 2- Mixture: Mixtures of Materials Mixtures When two or more different substances (or materials) are combined the result is a mixture. The substances or materials can be in the solid, liquid or gas state. Sometimes the different substances or materials are still visible after mixing. Sometimes they are not visible. Examples of Mixtures If you mix two solids together, you can usually see the different solids after mixing. For example, if you mix sugar and tea leaves you will see the sugar and the tea leaves. Other mixtures can be a combination of a solid and a liquid. In some examples the solid becomes invisible. For example, sand is visible in water but salt is invisible in water. Two or more liquids can also be combined to form a mixture. Sometimes liquids are visible after

9 mixing, such as water and oil. Sometimes liquids become invisible, such as water in a juice concentrated mixture. 8 Separating Mixtures In some of the mixtures the materials are clearly visible. In other mixtures, some of the materials disappear. There are many different ways to separate mixtures so that the materials are visible again. It is easier to separate substances we can see. We can physically separate these substances by sieving, filtering, hand sorting, settling or decanting. Method 1: Sorting by hand Hand sorting is physically picking out one material and separating it from the other material. This is best use for mixtures with large solids such as coins, beans, peanuts or sweets. This involves: Pouring the mixture onto newspaper or a piece of plastic Using your fingers or a pair of tweezers Picking out one of the materials from the others Method 2: Using a sieve This method refers to pouring mixtures through a sieve to separate the smaller solids from the larger ones. This involves: Pouring the mixture through a sieve into a bowl Shaking the sieve so that the small materials fall through The larger material will remain in the sieve. Method 3: Settling and decanting Settling refers to letting the mixture sit and waiting for it to separate on its own. This is easy to see with oil and water, and sand and water. This involves: Stirring the mixture Leaving the mixture in its container Allowing the mixture to stand until the two materials separate Carefully pouring off the top material from the other material

10 Method 4: Filtering Some mixtures are separated by pouring them through paper or other materials. You can do this with sand and water. This involves: Placing a funnel in a bottle Placing filter paper in the funnel Pouring the mixture through the funnel Allowing the liquid material to flow through the filter The solid material will remain in the filter or on the filter paper. 9 Summary A mixture consists of at least two different substances/materials mixed together. In some mixtures, the different substances are still visible after mixing. The substances in such mixtures can be separated by physical means such as sieving, filtering, hand sorting, settling and decanting. Activity 2 Investigate methods to separate a mixture Aim Determine which method of separating visible substances from mixtures are the best Hypothesis Write the hypothesis for this activity. State what you think the best method to separate each of the following mixtures is: A. Beans and peanuts B. Sand and salt C. Sugar and tea leaves D. Sand and water E. Oil and water Results a. Beans and peanuts are best separated by hands b. Sand and salt are best separated using a sieve c. Sugar and tea leaves are best separated using a sieve

11 10 d. Sand and water are best separated using a funnel and filtering paper e. Oil and water are best separated by using settling and decanting ==================================================================== Lesson 3 Unit 3 Solutions as Special Mixtures: Solutions Solutions A solution is a special mixture of a liquid and a solid. Solutions are uniform in appearance. This means that the solid cannot be seen in the solution. Dissolving a solid Dissolving is the process of mixing a solid and a liquid so that the solid is no longer visible. If the solid dissolves in the liquid it is said to be soluble. If it does not dissolve it is insoluble. Difference between melting and dissolving: Dissolving uses mixing to combine a solid and a liquid. Melting uses heat to convert one solid into a liquid. Summary Solutions are special mixtures. Some solutions can be made by mixing a solid and a liquid together such as sugar and water or salt and water. Solutions are uniform in appearance and the different substances cannot be seen after mixing. Activity 3 Mixing substances 1. Test what happens when the following materials are mixed in water: a. Mealie meal b. Flour c. Stamp d. Custard Powder e. Curry Powder

12 11 2. Write down the following questions: a. 2.1 Question to investigate b. 2.2 Hypothesis c. 2.3 Materials d. 2.4 Method e. 2.5 Results 3. Copy and complete the table in your book, with your conclusion Substances Appearance in Water Soluble or insoluble in water Mealie Meal Flour Stamp Custard Powder Curry Powder ==================================================================== Unit 4- Solutions as Special Mixtures: Soluble Substances Lesson 4 Dissolving a solid: Solutes and Solvent Solids that can dissolve are called solutes. The liquid in which a solute dissolves is called the solvent. Water is a unique solvent as so many substances can dissolve in it. The making of Sea Salt Over millions of years, salt from the land has washed into the sea. The salt has dissolved in the sea. Seawater tastes salty because of the dissolved salt. The seawater is the solvent. The salt is the solute. The solution is the mixture of the salt and water.

13 12 Discussion: How can the water and salt be separated? Activity 4 Methods of separating salt from water 1. Explain why the sorting by hand method would not work to separate salt and water. 2. Explain why sieving the water and salt through a sieve would not work to separate salt and water. 3. Explain why settling and decanting would not work to separate salt and water. 4. Explain why filtering would not work to separate salt and water. ==================================================================== Unit 5 Solutions as Special Mixtures: Saturated Solutions Lesson 5 Saturated Solutions When substances dissolve, solute particles become dispersed in the spaces between the solvent particles. When the spaces are full, there is nowhere else for the solute to go. The solute particles that are left out can be seen in the solvent. Imagine your classroom is a container of a solution. The chairs are the solvent and you and your fellow learners are the solutes. Once all the chairs (solvent) are taken by learners it becomes saturated. Saturated when a solution has no more space for any more particles of the solute. A natural example of a saturated solution: The Dead Sea is a lake that is on the border of Israel and Jordan. Over thousands of years water has flowed into the lake. Salts are dissolved in the water. The water evaporates and leaves the salt behind. The Dead Sea has become more and more salty. The water in the Dead Sea is saturated. No more salt can dissolve in the water. ====================================-*===============================

14 13 Unit 6- Solutions as Special Mixtures: Insoluble Substances Lesson 6 Insoluble Substances Water is known as a universal solvent. This means that many different substances can dissolve in water. This makes water very useful. There are also many substances that do not dissolve in water. These substances are insoluble. Oil is insoluble in water. Oil and water do not mix and oil will float on water. Insoluble Substances as Water Pollution Oil and sand are only two of many substances that are insoluble in water. Waste such as plastic bags, tins and bottles are all insoluble. They pollute our rivers and seas. Summary Soluble solids (solutes) can dissolve in water (solvent).some solids will not dissolve in water (insoluble solids). The substances in solutions cannot be separated by sieving, filtering, hand sorting, settling and decanting. Some solutes can be separated by evaporating the solvent. When substances dissolve, solute particles become dispersed in the spaces between the solvent particles. There is a difference between melting and dissolving. Melting involves heat and dissolving is the spreading of particles. ===================================================================

15 14 Unit 7- Dissolving: Rates of Dissolving Lesson 7 Rates of Dissolving Solutes dissolve in water but there are factors that can make the process faster or slower. The speed at which a solute dissolves is called the rate of dissolving. There are three factors that affect the rate of dissolving: Temperature of mixtures - The first one is the temperature of the water. Substances will dissolve faster in warmer water than in colder water. In warm water there are more spaces between the particles of water. This means there is more space for solute particles. Stirring versus shaking the mixture Stirring and shaking are both ways of mixing a solute with a solvent. Stirring is better at mixing the solute with the solvent than shaking the solution. Grain size of the solute The third factor is the size of the solute. A large grain of solute will take longer to dissolve than a small grain. This is because a grain is made up of particles of the solute. It takes time for the particles in a grain to break apart. The larger the grain, the slower the rate of dissolving will be. Summary Factors such as temperature of the mixture, stirring or shaking the mixture and grain size of the solute can affect the rate of dissolving.

16 15 Activity 7 Investigate the rate of dissolving and grain size Aim To investigate the rate at which a large grained solute dissolves compared to a small grained solute. Question to Investigate Does the size of the grain of salt affect the rate of dissolving? Hypothesis Write a hypothesis for this experiment. Materials o Two beakers o 125 ml of water in each beaker o A teaspoon o Fine Salt o Coarse Salt ==================================================================== Unit 8- Mixtures and Water Resources: Water Pollution Lesson 8 Water: A precious resource in South Africa South Africa is a very dry country compared to the rest of the world. The average rainfall for South Africa is 450 mm per year. The world average is 860 mm per year. Rain is unequally distributed in South Africa. If you live towards the western parts of South Africa you only receive rain a few times per year. The eastern parts receive rain regularly.

17 16 Water Pollution All water eventually runs into a river somewhere. If it is polluted water it will carry the pollution to the river. When pollution mixes with water it can dissolve and form a solution of solutes and solvents. The solution can be poisonous to organisms in the water. Some pollution is insoluble but still mixes with the water. South Africa s water is a precious resource that is under threat. There are several threats to our water. Some include: Insoluble substances Soluble substances Living germs Insoluble Substances Insoluble substances cannot dissolve in water. Not all insoluble substances are harmless. Things like oil, plastic, tyres, tins, glass and sewage waste are bad for the water and people using the water. Oil Pollution Oil can also pollute large amounts of water. Oil spreads as a thin layer on top of water. The oil kills wildlife and plants that depend on the river. Oils make the water undrinkable and it is impossible to remove all of the oil once it is in the water. Preventing Water Pollution Never throw waste into a river or on the ground. Never pour oil down a drain sink. Most insoluble items can be removed from a river by hand. Organised river clean-ups can remove many insoluble pollutants from our rivers.

18 Soluble Substances Soluble substances dissolve in water. This means it is very difficult to know if they are in water or not. They are virtually impossible to remove and cause pollution, which then makes the water undrinkable. 17 Examples of soluble pollution are: Fertilisers and insecticides used by farmers Chemicals used by factories Soap powder used for washing clothes Soap used by people to wash themselves Impact of Fertilisers on Rivers The effect of these pollutants is to poison the water so that nothing can live in it. It can also cause another problem called eutrophication. Eutrophication is when small plants called algae feed of the fertilisers, soaps and even some chemicals. The algae grow very fast and turn the rivers and lakes green. The water cannot be used for drinking. Some algae secrete poisons that make the water poisonous. When the algae die they sink to the bottom of the river or lake. They decompose and that process uses up all the oxygen in the river. Preventing Water Pollution: Use as little soap and detergents as possible. Use as little fertiliser as possible in your garden. Avoid using pesticides and herbicides in the garden. Living Germs Germs are living creatures that cannot be seen with the naked eye. Even clean looking water can have germs. Germs cause diseases and cause people to become ill. The most common illness carried by water is diarrhoea. Diarrhoea causes a person to lose lots of water. They cannot eat food and become very weak. The most common cause of death among young people is diarrhoea. The diarrhoea germ is common in areas where there are no proper toilets. The sewage from people is washed into rivers. People drink the water and become ill. This forms a cycle of infection.

19 18 To avoid contracting diseases that are transported in water, do the following: Do not play in or drink polluted water Wash your hands with soap before eating Report broken toilets Cycle of Infection: People have no access to toilets. sewage is washed into the rivers and lakes People become ill with diorrhoea. People can die from the illness. People drink the water or use the water for cooking. Children play in the water Summary Water can be polluted by insoluble substances such as oil and plastic, soluble substances such as soaps and fertilisers and germs. Activity 8 1. List three types of insoluble substances polluting rivers. 2. Add three more of your own examples of such substances (think of waste that lies next to roads) 3. What can you do at home to prevent water pollution and use water more wisely?

20 19 Activity 9 Discuss the following 1. Give examples of what can be done to stop the spread of diarrhoea germs. 2. Explain how the cycle of infection can be broken. 3. Explain the term water pollution. ==================================================================== Unit 9 Mixtures and Water Resources: Importance of Wetlands What is a Wetland? A wetland is shallow body of water with plants such as reeds. Other names for wetlands are marshes, swamps, seepage areas and food-plains. The water in a wetland can be salty or fresh water. Wetlands are the habitat for many unique animals and plants. A large wetland can cover an area of several square kilometres. A small wetland could be a puddle in a park or a garden. More than half (50%) of all the large wetlands in South Africa have been destroyed. How Wetlands control floods When a river floods, a wetland provides a place for water to spread out and slow down. Wetlands are filled with plants that slow down the flow of water. How Wetlands clean polluted water The slow flowing water allows insoluble substances to settle. Sand and silt sink to the bottom of the wetland. The water becomes clear. Plants absorb nutrients from the water. Many of the nutrients are soluble substances that pollute the water. Plants can also absorb the soluble nutrients that cause eutrophication. Even germs that cause diarrhoea are eaten by microscopic organisms. Water may become drinkable after flowing through a wetland. Case Study Edith Stephens Wetland Park Cape Flats In the middle of an area of Cape Town called Philippi there is a seasonal wetland. It is called the Edith Stephens Wetland Park. Ms Stephens was a botanist. She cared

21 20 about the wetlands on the Cape Flats. She bought a piece of land so that it could be preserved as a wetland. She was not a wealthy woman, but she cared a lot about the environment. The wetland is the home of a plant that has existed for 200 million years. The plant is a small fern called Isoetes (pronounces: i-so-eat-tease). Today many people in Philippi benefit from the wetland and use it as a place to relax and watch birds. We need to think about the future and act more like Edith Stephens. Activity 9 1. Read about the Edith Stephens wetland on the Internet 2. Explain why wetlands are important 3. List 4 of the plants and animals that make the Edith Stephens Wetland Park their habitat 4. What is the quality of the water in the Park? 5. Write a report on the importance of wetlands. Use the answers to the above questions as a body for your report. Summary Wetlands are important ecosystems. They filter dirty water and are a habitat for many species of plants and animals. Wetlands are being destroyed by housing, agriculture and industries. ==================================================================== Unit 10 Process to Purify Water: Clean Water Lesson 10 Living things such as plants and animals rely on water. Life cannot exist without it. Animals and water Blood is made up of about 55% water. This helps to carry nutrients around the body of animals. All animals would eventually dehydrate without water. Not only does water keep an animal cool but water is also needed to digest food and remove waste. People depend on water for the same reason. Without clean water, people would also not be able to grow food, keep clean or be healthy.

22 Plants and Water Plants need the nutrients that are dissolved in water. Some animals that live in wetlands deposit their waste in the water. The waste contains nutrients that the plants can use. The plants absorb the nutrients through their roots and are used to make food for the plants. The Importance of clean water Water management is everyone s responsibility but the municipality officials of towns and cities have the responsibility of looking after the water treatment facilities. The municipality must purify water to keep people healthy. How a water treatment facility works Water treatment plants are places where water from dams, rivers and aquifers are cleaned. To clean the water the following steps are taken: 21 Water is pumped to the water treatment plant. Water is filtered through a sieve. Water is then filtered through a very fine material called a membrane. A chemical called chlorine is added to kill any germs. Other chemicals are added to remove any bad tastes or smells. The water is pumped to factories and houses. There are four ways to purify water: Boiling, Filtering, Settling and Chemical treatment. Boiling Water Boiled water is heated to kill any germs in the water. This method uses a lot of electricity or firewood and does not remove soluble or insoluble pollution. Filtering Water Pouring water through a funnel and filter paper removes most of the insoluble pollution such as sand. But germs can pass through the filter paper. So can soluble pollution such as salts and chemicals. Settling Water Water that is allowed to settle will appear to be clean but not all the insoluble pollutants will settle. Germs and soluble pollutants are not removed. Chemical Treatment Chemicals or iodine can be added to water to kill germs but these chemicals are expensive and can make the water taste awful.

23 Activity 10 Draw up a table that compares the advantages and disadvantages of each method of water purification listed above Advantages Activity 11 Filter and Purify Water Disadvantages Imagine you are stranded in a desert. You come across a small pool of water. You are desperately thirsty but you have to clean the water before you can drink it. Describe how you would purify the water Write your answer in the form of a paragraph (6-10 lines). Activity 12 Science language activity Use the words in the box to complete the sentences 22 solids liquids gases particles big small regular 1. Matter is made up of tiny that are moving. 2. In, the particles are packed close together in a pattern and cannot move freely. They have spaces between them. 3. In, the particles have spaces between them but can move around each other. 4. In, the particles have spaces between them and can move in all directions. 5. Copy and complete the following table Write two facts about the arrangement of particles How do particles move Draw the particle arrangement Solid Liquid Gas ====================================================================

24 Unit 13 Skills Focus: How to Follow Steps of a Scientific Investigation 23 Key words: Prediction when you say what you think will happen Data- processed information presented in a structured way Conclusion something you decide based on the results of your investigation Evaluate to look at what you have done and to think of how to do it better next time. Steps: 1. Observe and ask certain questions about what you have observed(how, what, when, where and why) 2. Make a prediction, a statement about your guess of the results of your investigation. 3. Plan your investigation (materials, equipment and methods) 4. Conduct your investigation 5. Record your findings 6. Interpret data 7. Draw a conclusion 8. Evaluate your investigation ====================================================================