YEAR 8 - SCIENCE REVISION. Final Exam

Transcription

1 YEAR 8 - SCIENCE REVISION Final Exam 1. Give a comparative study of Copernicus model of solar system and Kepler s model of solar system. 2. Why do we follow Kepler s model today? 3. The figure below shows what scientists over 1000 years ago thought the solar system was like. (a) Give one way that the historical model of the solar system shown in the figure above is different from what we now know about the solar system (b) Give one way that the solar system shown in the figure above is the same as what we now know about the solar system (c) The first artificial satellite to orbit the Earth was launched into space in Describe the orbit of an artificial satellite (d) What provides the force needed to keep a satellite in its orbit? Tick one box. Friction gravity tension

2 2.The photograph shows a sample of limestone. State what evidence in the photograph shows that the limestone is a sedimentary rock (b) Complete the sentence by putting a cross in the box next to your answer. Limestone is an important raw material. In industry limestone is not used as a raw material to make A cement B concrete C glass D marble (ii) Part of the reactivity series is shown Magnesium iron lead copper Most reactive Least reactive State if the following sentence is True or False. If it is wrong write down the correct statement. i. Iron gives out more bubbles with acid than magnesium ii. Lead is less reactive than copper iii Magnesium is most reactive than all the other given metals.

3 3. The first indication of a greenhouse effect in the atmosphere caused by humans was published by Swedish scientist Svante Arrhenius in He put forward the theory that the increase in industrial coal combustion could cause the atmospheric concentration of CO2 to double. The ensuing anthropogenic greenhouse effect would lead to a global warming of 4 6 C. However, because Arrhenius couldn t substantiate his theory with measurements, his research attracted little public attention. Today almost all scientists agree that the Earth s climate began to warm up a few decades ago, an outcome which can only be explained by human intervention. The main cause is the so-called anthropogenic greenhouse effect. The factors responsible are greenhouse gases, particularly carbon dioxide (CO2), which since the Industrial Revolution has been pumped into the air in large quantities, additional to the naturally occurring concentration of greenhouse gases. a) Describe the graph shown above b) Based on the information given what is most important to know about Global Warming? c) List few steps you will take to check global warming. d) Identify how your step will help check global warming.

4 4. Use words from the box to complete the sentences correctly. Not all the words will be used. burn, flames, hot, fire extinguisher, wet, wood a To light a bonfire, you need to make the wood very b We can tell when the wood starts to burn, because we can see c To put the fire out, we can use a Draw lines to link each of the words on the left with its meaning shown on the right. combustion fuel hydrocarbon oxidation a reaction when a substance combines with oxygen a substance made of only hydrogen and carbon a substance containing stored energy that can be released during burning a reaction when burning happens 6. The apparatus shown below is used to show what happens during the combustion of a hydrocarbon fuel. Tick one box to complete each sentence in parts i, ii and iii below. i.the thermometer will show that during the experiment the temperature will A decrease B increase C stay hesame D fluctuate

5 The blue cobalt chloride paper will change to pink because ii. A water is being produced. B oxygen is being produced. C carbon dioxide is being produced. D heat is being produced iii The limewater will change from clear to A pink B blue C dark D cloudy Explain your answer to part iii. 7).The diagram below shows a section of part of the earth's crust: a) Which of the layers contains the youngest sedimentary rock? b)which of the layers contains metamorphic rock? c) Describe how granite is formed.

6 8.The diagram below shows the relative positions of Earth and the Sun at a certain time of the year. a) Based on the diagram, which season is occurring in the Southern Hemisphere of Earth? b) Which of the following statements best explains why the tilt of Earth on its axis causes summer to be warmer than winter in the Northern Hemisphere? A. The warm ocean currents flow from the tropics to the Northern Hemisphere in the summer. B. The rays of the Sun strike the Northern Hemisphere more directly. C. The greenhouse effect increase in the Northern Hemisphere in the summer. D. The Northern Hemisphere is closer to the Sun in the summer. c) In which direction was the Earth s axis pointed at the time of this photograph in Lowell, MA (a lot of snow had just fallen ) Explain you answer.

7 9.A tea light is a type of candle. The diagram shows apparatus used to investigate the effect of the height of a candle on the time taken before the candle goes out. i.which is the independent variable in the experiment? Tick one box. A height of candle B the material of the container C size of container D time taken for candle to go out ii.which is the dependent variable in the experiment? Tick one box. A height of candle B the material of the container C size of container D time taken for candle to go out The other variables need to be controlled. Explain why. Choose one of the control variables and suggest how this variable could be controlled The diagram shows an incomplete fire triangle. What is the missing word on the triangle? b Explain what the fire triangle shows.

8 c) Explain how water helps to put out a fire d) Explain why you should not use water on burning oil 10) ) a) Peter tried to obtain a mixture of red and green light. He used white light from a spotlight and slotted a red filter and a green filter in front of it as shown below. The diagram below represents Peter s experiment. (i) No light reached the screen. Explain why. (ii) Peter cut a circular hole in the green filter. Describe what Peter would see on the screen. (b) Peter used two spotlights to shine a mixture of red and green light on to some red curtains. (i) What colour did the red curtains appear in this light? (ii) Give the reasons why they appeared this colour. 2 marks 1 mark 3 marks 11) When looking down into the calm water behind the pier the student sees a fish. Complete the diagram to show the path of a ray of light from the fish to the student. You should include the normal in your diagram.

9 12) Some children have a large box floating upright on a pond. The pressure on the bottom of the box is 0.5 kpa The bottom of the box has an area of 2000 cm 2. Calculate the force from the water acting on the bottom of the box. force from the water =...N Q13). Weighing in liquids (a) Jerome weighs a marble block in air and in water. Weight is a force. Look at the picture. (i) Name the equipment that Jerome uses to measure the force of weight on the block mark (ii) What units does this equipment use to measure the force of weight? (b) The marble block weighs less in water than in air. 1 mark Weight of the marble block (units): in air in water Tick ONE box below to explain why the marble block weighs less in water The string shrinks in water. There is an upward force from the water. Forces cannot act very well in water. There is an upward force from the air. 1 mark

10 (c) Jerome weighs the block in other liquids to see what happens. Here are his results. Weight of the marble block (units): in salty water in oil in washing-up liquid Jerome says: I think the marble block will weigh less in any liquid I try than it does in air. (i) Do Jerome s results suggest that his prediction is sensible? Yes No (ii) Use Jerome s results to explain your answer mark Q14) Draw the molecular structure of the following a) Carbon dioxide b) ammonia c) nitrogen molecule Q15) Write down the function of the following organs in human digestive system a) Stomach b) Small intestine c) Large intestine d) Liver

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