PREFACE. Gain a better understanding of selected topics from reading notes and watching educational videos.

Transcription

1 PREFACE Every child can be a scientist and carry out experiments in the comfort of their own homes! introduces and provides opportunities for children to do a host of simple yet you-can-do-it awesome science experiments. Nineand ten-year-old children can explore and satisfy their curiosity about the world around them through hands-on experiments. In the process of doing and observing, they become active participants, confident of being in charge of constructing their own learning. The end goal is for children to enjoy and value science as an important tool in helping them explore their natural and physical world. Identifiable Topics Based on 5 Themes The themes covered Diversity, Systems, Cycles, Interactions and Energy are based on the Singapore science curriculum. The topics under each theme are familiar to children as they complement what they are learning in school. 31 Engaging Experiments Most of these experiments are not commonly done in school. These additional experiments help deepen the children s understanding of the topics. They also intrigue children and ignite their curiosity and interest to want to do and carry the discussion of the topics further with their parents and peers. By conducting experiments, children are encouraged to be creative and confident. Some of these experiments require adult supervision so do look out for. Acquired Skills and Processes Children inadvertently pick up skills observation, comparing, classifying, using apparatus and equipment, communicating, inferring, formulating hypothesis, predicting, analysing, generating possibilities and evaluating, and processes such as creative problem-solving, decision-making and investigation when carrying out the variety of science experiments found in the topics. Ready-made Cut-outs Cut-outs for selected experiments are found in the appendices. Clear instructions on how to use the cut-outs can be found in the procedures of the experiments as well as on the appendices. 7 Keyword Challenges After each set of experiments on a topic, children can complete a crossword puzzle. The answers to the questions in the crossword puzzles are must-know keywords essential to understanding the topics. Having these light work activities will help the children to understand better scientific concepts. Complete Answers Answers are given as a reference. Gain a better understanding of selected topics from reading notes and watching educational videos.

2 CONTENTS Theme Topic Title Page DIVERSITY Different Types of Living Things The World of Materials 1 Yeast in Action 1 2 What s in Your Food? 3 3 Natural Dye 5 4 Bean Sculpture 7 Keyword Challenge What s a Circuit Tester? 13 6 The Force of a Wind 17 7 Chromatography 19 8 Propelling a Balloon 23 9 A Mini Fire Extinguisher Volume of an Object Hydrometer 29 Keyword Challenge 2 31 SYSTEMS Plant System 12 Paper Helicopter A Secret Message Browning in Apples 37 Keyword Challenge 3 39 CYCLES Matter 15 A Bubbling Experience Evaporation Separating a Mixture 45 Keyword Challenge 4 47 INTERACTIONS Magnets 18 Magnetism by Stroking Method A Homemade Compass Electromagnet 53 Keyword Challenge 5 55

3 Theme Topic Title Page ENERGY Light 21 How to Make a Viewer How a Periscope Works Light Travels in a Straight Line How Does the Human Eye See? A Luminous Jet 67 Keyword Challenge 6 69 Heat 26 Reactions Involving Vinegar Effect of Heat Heating Effect of Electric Current Effect of Heat on Glowsticks The Reverse Balloon Heat Absorption 81 Keyword Challenge 7 83 APPENDICES Appendix 1: Cut-outs for The Force of a Wind 87 Appendix 2: Cut-outs for Paper Helicopter 91 Appendix 3: Cut-outs for How to Make a Viewer 93 Appendix 4a: Cut-outs for How a Periscope Works 95 Appendix 4b: Cut-outs for How a Periscope Works 97 ANSWERS... A1 - A4

4 Name: Class: Date: DIVERSITY: Different Types of Living Things 1 Yeast in Action Introduction Yeast is a microorganism used in the making of bread. Yeast feeds on the sugar present in the dough and produces carbon dioxide which causes the dough to rise. This process, known as fermentation, ensures that the bread, when baked, will turn out light and soft and not hard like cookies! Aim To observe that yeast produces carbon dioxide when it feeds on sugar Materials G 100 ml warm water in a cup G 1 tablespoon castor sugar G 1 sachet of dried yeast (11 g) G 1 ziplock bag (measurement: approximately 17 cm by 17 cm) G a plate Procedure 1 Dissolve the castor sugar in the cup of warm water. 2 Pour the sugar solution into the ziplock bag. 3 Empty the sachet of yeast into the ziplock bag. Carefully remove any excess air in the bag before sealing it. 4 Place the ziplock bag on the plate. 5 Observe what happens after 20 minutes. Singapore Asia Publishers Pte Ltd 1 1 Yeast in Action

5 Conclusion Yeast is a 1 that feeds on sugar. When the yeast mixes with the sugar solution, it feeds on the food and releases the gas, 2. This gas is trapped in the sealed ziplock bag, causing the bag to 3.? 1 Why do you think warm water was used in this experiment? 2 What would happen if we had used hot boiling water for the experiment instead? Do you know? A group of local scientists from Nanyang Technological University, Singapore (NTU) found that a type of yeast called Rhodosporidium toruloides is able to feed on the fatty acids in waste oil and at the same time, produce the health supplement, carotenoids. Currently, many companies are using chemicals like methanol and chloroform to treat waste oil but these pose a threat to the environment. The use of this species of yeast to treat waste oil is definitely more environmental friendly. Carotenoids, which are in great demand globally, are costly to extract and purify. However, this yeast is able to produce it naturally, thus reducing the cost of production significantly. Carotenoids are beneficial to health as they have been shown to reduce the chance of developing cancer and eye diseases. The discovery of this species of yeast has, therefore, benefitted humankind. 2 Singapore Asia Publishers Pte Ltd 1 Yeast in Action

6 Name: Class: Date: DIVERSITY: Different Types of Living Things 2 What s in Your Food? Introduction Iodine is a yellowish brown solution that reacts with starch and turns it blue-black. Food that is derived from plants contains starch. Plants carry out photosynthesis and make food in the form of glucose. When there is excess glucose, it will be converted into starch for storage. Aim To infer that starch is present in some food Materials G 50 ml hot water in a beaker G 1 tablespoon cooked rice G ¼ teaspoon starch powder G 6 small disposable bowls G a slice of green banana G a slice of apple G a piece of biscuit G a piece of cooked chicken meat G a piece of fish G a bottle of iodine G a dropper Singapore Asia Publishers Pte Ltd 3 2 What s in Your Food?

7 Procedure Part 1: Introducing the iodine test 1 Dissolve the starch powder into the beaker of hot water. 2 Using the dropper, add two drops of iodine into the starch solution. 3 Observe what happens. Part 2: Iodine test for the food samples 1 Place each food sample in a bowl and add a few drops of iodine to each sample. 2 Record your observations in the table below. Food sample green banana apple cooked rice biscuit chicken meat fish Did the iodine turn dark blue? (Circle your answer.) Table 1: Results of the iodine test? 1 Which food samples contain starch? 2 Do the food samples named in 1 come from plants or animals? Which foods have starch in them? Go to 4 Singapore Asia Publishers Pte Ltd 2 What s in Your Food?

8 Name: Class: Date: DIVERSITY: Different Types of Living Things 3 Natural Dye Introduction Natural dyes are colourants that are mainly derived from plant parts such as roots, fruit, leaves and bark. Interestingly, evidence of textile dyeing could be found dated as far back as the Neolithic period. Many natural dyes require the use of chemicals that help to bind the dye to the textile fibres. In the past, people used chemicals such as vinegar, salt or even ammonia from stale urine. Aim To demonstrate that the coloured pigment from plants can be used to dye cloth Materials G 600 ml water G 1 tablespoon vinegar G 1 cup of plant parts (red onion skin or sliced beetroot or cranberries, etc.) G a small piece of cotton cloth G a sieve G a container G a pair of tongs G a pair of goggles G a pot G some cold water G use of a kitchen stove Procedure Part 1: Treating the cloth 1 Pour 300 ml of water into the pot. 2 Use the pair of tongs to place the piece of cotton cloth into the water. 3 Add the vinegar. 4 Put on the goggles. 5 Turn on the stove and let the cloth simmer in the mixture for 15 minutes. Singapore Asia Publishers Pte Ltd 5 3 Natural Dye

9 6 Turn off the stove and leave the cloth in the pot to cool for about 2 hours. 7 Use the pair of tongs to remove the cloth and rinse it with cold water. 8 Leave the cloth to dry overnight. Part 2: Dyeing the cloth 1 Pour 300 ml of water into the pot. 2 Add the sliced beetroot into the pot of water. 3 Put on the goggles. 4 Turn on the stove. 5 Allow the water to boil with the sliced beetroot in it for at least an hour. 6 Use the sieve to strain out the beetroot. Set the container of dye solution aside. 7 Pour the dye solution back into the pot. Boil the dye solution. 8 Use the pair of tongs to place the treated cloth into the pot of boiling dye solution. Allow it to simmer for 15 minutes. 9 Turn off the stove and leave the cloth to soak overnight in the dye bath.? 1 Do you think the cloth would be stained red if it was soaked in cold beetroot solution? 2 Charmaine wants to find out whether vinegar or citric acid is a more effective substance to treat the cloth. What are the variables that she needs to keep constant when she is treating the cloth with both substances? Do you know? In the 1850s, due to the unregulated use of synthetic dyes, food poisoning was common. Artificial colourings were used to disguise food of poor quality. They were also used in imitation foods so that they could be passed off as the original. Most appalling were manufacturers who used poisonous chemicals as colouring for sweets to make them more appealing to children! Fortunately, with better monitoring in place over the years, many harmful synthetic colourings have been removed from the processed food that is being consumed today. However, natural and fresh foods are still the best, the safest and the healthiest. 6 Singapore Asia Publishers Pte Ltd 3 Natural Dye

10 6 The Force of a Wind 1. Colour the windmill. 2. Cut along the solid lines. 3. Fold back gently so that all the dots meet the dot in the centre. DIVERSITY: The World of Materials Experiment: The Force of a Wind 87 Pinwheel Singapore Asia Publishers Pte Ltd Appendix 1

11 DIVERSITY: Different Types of Living Things 1 Yeast in Action Conclusion 1. microorganism 2. carbon dioxide 3. inflate / expand 1. Yeast cells would only be active in warm water. 2. The yeast cells would die due to the high temperature. 2 What s in Your Food? Did the iodine turn dark blue? Yes; No; Yes; Yes; No, No 1. They are the green banana, cooked rice and biscuit. 2. They come from plants. 3 Natural Dye 1. No. Heat destroys the plant cells and the coloured pigments in the cells are then released into the water to stain the cloth. 2. The variables that she needs to keep constant are: size of the two pieces of cloth, amount of hot water used, the amount of citric acid and vinegar used, the time the two pieces of cloth are left simmered in the solution, the amount of cold water the two pieces of cloth are rinsed in and the time both pieces of cloth are left to dry. 4 Bean Sculpture Conclusion 1. softens 2. swell 3. dries 4. shrink 1. (a) Seeds need warmth to germinate. The seeds in the refrigerator did not have sufficient warmth. Hence, they could not germinate. (b) Soon after the first leaves appeared, the young plants would need sunlight to make food so that they could continue their growth. (c) root Keyword Challenge 1 Down 1. vertebrates 2. blowholes 3. insects 4. birds Across 5. fungi 6. scales 7. microorganisms 8. ferns DIVERSITY: The World of Materials 5 What s a Circuit Tester? Results Yes; No; No; No; Yes; No; Yes; Yes; No; Yes Conclusion Non-conductors of electricity paper Styrofoam cloth handle of a pair of scissors wooden part of a pencil Conductors of electricity aluminium foil paperclip blade of a pair of scissors pencil lead coin Question 1. Water is a conductor of electricity and we will get an electric shock. 6 The Force of a Wind 1. It is light. 2. Plastic 7 Chromatography Conclusion 1. speeds / rates 2. slower 3. chromatography Question 1. The graphite of a pencil would not dissolve in solvents but the ink of a pen would dissolve in the solvent used and, hence, interfere with the results on the chromatogram. Singapore Asia Publishers Pte Ltd A1