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S240 Analytical Science: Health, heritage and environments Are You Ready For S240? Contents 1 Introduction 2 2 Suggested prior study 3 3 Self-assessment test 4 3.1 Mathematics (Questions 1 - 12) 4 3.2 Biology (Questions 13 - 15) 7 3.3 Earth Sciences (Question 16) 8 3.4 Physics and astronomy (Questions 17 - 18) 8 3.5 Chemistry (Questions 19 - 25) 9 4 Other skills 11 5 Answers to self-assessment test 11 6 If more preparation is needed before studying S240 16 7 Further reading 17 8 Your score sheet 17 Copyright © 2011 The Open University Printed in the United Kingdom SUP 11111 1 1.1 *SUP1111 11* 1 Introduction S240 Analytical Sciences: Health, heritage and environments covers a number of topics that draw upon knowledge and understanding of the basic scientific disciplines of biology, chemistry, Earth sciences, and physics and astronomy such as might be gained through successful study of The Open University’s main Level 1 science course (S104 Exploring science). You should therefore be interested in the whole range of scientific disciplines rather than, for example, primarily biology or the physical sciences. Moreover, many of the topics covered in the module demand an interdisciplinary approach to science rather than treating the different scientific disciplines as separate entities. As with any study of science, a certain level of competence in numeracy and other mathematical skills is required to study S240. Again, this level is indicated by the treatment of these skills in S104. It is necessary to have access to the computing equipment to participate in computer-mediated conferences, be prepared to both contribute to ‘discussions’ and to ‘listen’ to the contributions of others and possess a basic level of ICT literacy. Some of the resources and/or teaching are delivered online so access to a computer with an online connection will be required. If you are unsure whether you have the necessary computer equipment, check the Personal Computing for OU Study webpage for S240. There is a link to this on The Open University’s Courses and Qualifications webpage for S240. You are expected to be able to write clearly, correctly and logically about important contemporary issues that have an underlying scientific basis, drawing upon both the science itself and the module themes. Activities embedded within the materials and tutor-marked assignment (TMA) questions provide opportunities to develop this important skill. Thus, in order to assess whether you are ready for S240, you need to consider a number of questions: • Do you have the necessary knowledge and understanding of science? • Do you have the necessary skills of numeracy and mathematics? • Are you motivated by a range of scientific disciplines? • Are you interested in an interdisciplinary approach to science? • Do you accept that disciplines outside the natural sciences have legitimate contributions to make to many topics that have an underlying scientific basis? • Are you prepared to work with others to test and clarify your own understanding of such topics? This document provide opportunities for you to test whether your current knowledge and understanding of the individual scientific disciplines and your skills of numeracy and mathematics are at least at the level assumed at the start of S240. The answers are given in Section 5. In addition to deciding which answers are correct, you ought to consider whether the questions and answers include more than just a few technical terms whose meanings elude you. If you have passed S104 (or any of its predecessor courses, S100–S103), then you should have little or no difficulty in understanding and answering the questions. If you have a different background in science, these questions should help you judge whether this is at least equivalent to having studied S104. Of course, some or all the material may be familiar to you but, in trying to answer the 2 questions, you might discover that you are a little ‘rusty’. If this is the case, then it would be as well to look back over the relevant parts of your previous module(s) and then try the questions again. However, S240 includes a very succinct ‘primer’ outlining aspects of science that are essential for and assumed by what follows. Section 6 gives some advice about what you might do if you appear to need more preparation in one or more areas before you begin S240. Assuming that you are academically ready to commence S240, Section 7 makes some suggestions about further reading that you might undertake while you wait for the module to begin. 2 Suggested prior study This module is for you if you have already studied a fairly broad range of science disciplines (that is, not only life sciences or the physical sciences) at Level 1. You should have studied either: • Exploring science (S104) (or the discontinued module S103) • Introducing health sciences: A case study approach (SDK125), Or a combination of 3 science short modules covering the physical, chemical and biological sciences. Particularly relevant OU science short modules are: • Science starts here (S154) is specifically for students who have done little or no science before, and whose maths is rusty (or non-existent!). • Maths for science (S151) is for anyone wanting to take a Level 2 science module with The Open University, but lack confidence in using mathematics as a tool in science. • Empire of the microbes (S171) explores the intriguing world of bacteria, viruses, and other microscopic organisms. It enables students to try out a new area of study before you commit to a longer module, or top up knowledge and skills between longer modules. • Elements of forensic science (S187) is for people who have a basic knowledge of chemistry, DNA and genetics and who want to understand how this science is applied to crime scene investigations. • Molecules, medicines and drugs: a chemical story (SK185) describes the development of a variety of drugs and explores chemical strategies to minimise the risk of infection and disease. • Introducing astronomy (S194) covers the exploration of our solar system; the discovery of planets orbiting other stars; the birth, life and violent death of stars; and the creation of the Universe itself. • Archaeology: the science of investigation (SA188) develops an appreciation of the processes involved in the discovery, investigation and interpretation of artefacts and archaeological sites, and apply scientific techniques used in the field and laboratory. Alternatively you could have studied equivalent courses at another institution. You should be able to understand a number of basic mathematical concepts and have mathematical skills to at least GCSE level. 3 3 Self-assessment test Try to answer the following self-assessment questions (the answers are given in section 5 of this document; there is a score sheet in section 8 to record your scores). This will help you to judge your level of knowledge of some of the key concepts listed above. We’ve included a score sheet in the answers section where you can note down your own assessment of how well you demonstrated your understanding. 3.1 Mathematics Question 1 Work out the answers to the following sums, using your calculator as appropriate: (a) 6998 − 15774 (b) (−5) + (−9) (c) (8 + 6) × (5 − 2) (d) Find x and express its value to three significant figures. (a = 15 and b = 81) x= a × 100% b Question 2 Calculate to two significant figures the volumes of boxes with the following dimensions: 3 (a) 2.0 m × 8.0 cm × 9.0 mm (express the answer in cm ); 3 (b) 87 cm × 9.0 cm × 8.0 m (express the answer in m ). Question 3 The following figure shows a general plot of temperature change with altitude where the temperature at sea-level is 20.0 °C. (a) What is the temperature at a height of 300 m above sea-level? height above sea level/metres (b) How much would you expect temperature to drop when ascending from sealevel to a height of 1 km? 1200 1000 800 600 400 200 0 12 14 16 18 temperature/ C 20 4 22 Question 4 If the amount of rainfall collected in a rain gauge, expressed in mm, for 5 consecutive days are: 22.4, 13.5, 12.6, 23.3, and 4.0 what is the average rainfall over these 5 days, to one decimal place? Question 5 The volume V of a sphere of radius r is given by the formula: V = 4 3 πr 3 What is the volume of a sphere of radius 5 m? (a) 105 m 3 (b) 167 m 3 (c) 500 m 3 (d) 524 m 3 Question 6 −1 The concentration of a chemical in solution is 50 µg l . Given that a cubic metre −3 is equivalent to 1000 litres, express this concentration in mg m . Question 7 Rearrange the following equation: h = gk − f to give an equation for g. Question 8 number of cases/103 Reading from the following graph: 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 year 5 (a) How many cases were there in 1993? (b) In which year was there the lowest number of cases? (c) What was the mean rate of change in the number of cases between 1996 and 2001 inclusive? Question 9 This question deals with some of the conventions and skills associated with using graphs. (a) If the scale on the vertical axis (y-axis) is temperature in degrees Celsius, how would you write this? (b) The Figure below shows the travel time of a seismic wave from its origin to a point on the Earth’s surface, plotted against distance from the earthquake’s epicentre. (i) Which of these quantities is the independent variable? (ii) How long does it take for the seismic wave to travel 150 km? (iii) Why does the line of the graph not go exactly through all three points? travel time after earthquake occurred/s (c) Work out the gradient of the line. Give your answer in s/km to 2 significant figures. 40 30 20 10 0 100 200 distance from epicentre/km Question 10 The diameter of the common marine phytoplankton Emiliania huxleyi is 0.00000015 m. Express this number in scientific notation. Question 11 In science, the Kelvin temperature scale (abbreviated to K) is often used in preference to the more well-known Celsius temperature scale. 0 Kelvin is equivalent to –273.15 °C, and a change in temperature of 1 K is equal to a change of 1 °C. Which one of the following is equivalent to 10 °C? (a) –283.15 K 6 (b) –263.15 K (c) 263.15 K (d) 283.15 K Question 12 –2 A substance contains 3.5 × 10 particles per cubic metre. How many particles 4 3 will there be in a volume of 10 m ? –2 (a) 3.5 × 10 (b) 350 (c) 35 (d) 3.5 3.2 Biology Question 13 Use the list of words below to fill in the gaps in the following passage. All living cells are surrounded by a selectively permeable ____________. Most cells in ____________ organisms possess an organelle called the ____________ in which are located the _____________ that carry most of the genetic information of the organism. These structures consist of a long doublestranded molecule called _______________________ (abbreviated to____) and various _____________ molecules. In _______________ organisms (such as bacteria) the circular molecules that carry the genetic information lie naked in the ____________. Bacteria and viruses which infect humans are known as ____________. The immune system produces ________________, which try and eliminate invading organisms._ ___________ bind tightly and specifically with antigens to produce a complex which can be removed by the immune system. The biochemical processes in the body responsible for ___________are mediated by proteins called ________. These are very specific and bind compounds called ___________. Some of the words are not used at all while others may be used more than once: DNA, cell wall, chloroplasts, chromosomes, eukaryotic, cytoplasm, deoxyribonucleic acid, enzymes, substrates, cell membrane, antibodies, mitochondria, nucleus, photosynthesis, prokaryotic, pathogens, metabolism, nucleotides, protein Question 14 Identify and correct the two wrong statements among the following. (a) Mitosis is the process of cell division that gives rise to gametes. (b) Gametes are haploid. (c) A homozygote possesses two copies of the same allele of a particular gene. (d) Meiosis is the process of cell division that gives rise to gametes (e) Chromosomes are made of protein. 7 Question 15 Identify and correct the two wrong statements among the following. (a) Adenine, cytosine, guanine and thymine (A, C, G and T) are RNA nucleotides. (b) The ‘central dogma’ in biology is ‘DNA makes RNA makes protein’. (c) The appearance of an organism is one aspect of its phenotype. (d) There are only 23 chromosomes in each cell in our bodies (e) Enzymes are biological catalysts 3.3 Earth Sciences Question 16 Identify and correct the two wrong statements among the following. (a) Rocks are categorised as igneous, sedimentary or metamorphic. (b) Metamorphic rocks have had their minerals altered by high temperature and/or pressure. (c) The Earth is about 4600 billion years old. (d) The more rapidly magma cools, the larger the resulting crystals. (e) Quartz, feldspar and mica are the principal minerals of granite. 3.4 Physics and Astronomy Question 17 Identify and correct the two wrong statements among the following. (a) The Moon is Earth’s only natural satellite. (b) Although comets pass through the Solar System, they do not orbit the Sun. (c) A meteor is a fragment of a meteorite that has reached the Earth’s surface. (d) Planets and other bodies rotate around the Sun in elliptical orbits. Question 18 Identify and correct the two wrong statements among the following. (a) Monochromatic light consists of photons, all of which have exactly the same energy. (b) The energy of a photon of light is proportional to the frequency of the light. (c) If an atom undergoes a transition from one energy state to a lower energy state, a photon will be absorbed. (d) When an atom is in its ground state, it has its maximum possible energy. (e) The atomic spectrum of each element is unique. 8 3.5 Chemistry Question 19 Carbon dioxide has the chemical formula CO2. Which one of the following statements is correct? (a) The carbon dioxide molecule has 2 carbon atoms and 2 oxygen atoms. (b) The carbon dioxide molecule has 1 carbon atom and 2 oxygen atoms. (c) The carbon dioxide atom always comes in pairs. (d) The carbon dioxide atom is made up of a carbon atom and an oxygen molecule. Question 20 Complete the following table of common chemical elements and their chemical symbols. Element Symbol Al C sodium Si calcium oxygen sulfur Fe magnesium Question 21 Use the list of words below to fill in the gaps in the following passage. A chemical ___________ is a substance that consists of one type of ___________ that has a unique _____________ corresponding to the number of ____________ charged ______________ in its nucleus. A neutral atom has the same number of ____________ charged ___________. Atomic ___________ also contain varying numbers of uncharged _____________. Atoms with the same numbers of protons and neutrons belong to the same _____________of an element. The total number of protons and neutrons (which together are called ______________) in an atom gives its ____________. A _____________ is created by the ___________ of one or more electrons from a neutral atom. If an atom should ______________ one or more electrons it becomes a _______________. atom, atomic number, electrons, element, gain, isotope, loss, mass number, negative ion, negatively, nuclei, neutrons, nucleons, positive ion, positively, protons. Question 22 Methane (CH4), also known as natural gas, burns in the presence of oxygen to yield carbon dioxide and water. The reaction also releases energy. Balance the overall chemical equation for this reaction: CH4 + O2 = CO2 + H2O 9 Question 23 Identify and correct the two wrong statements among the following. (a) A neutral solution has a pH of 7. (b) pH is a measure of the concentration of hydrogen ions (H+) in a solution. (c) Acidic solutions have a higher pH than solutions that are alkaline. (d) A solution can be made less alkaline by the addition of an acid. (e) If carbon dioxide (CO2) dissolves in water, the water becomes more alkaline. Question 24 Oxidation is said to occur when the proportion of oxygen in a compound increases. Conversely, reduction occurs when the proportion of oxygen decreases. The term oxidation is also used more generally to include any reaction in which an atom loses electrons. Conversely, reduction involves a gain of electrons. For example, on going from left to right in Reaction 7, a magnesium ion is reduced to magnesium metal by gaining two electrons. At the same time, a molecule of hydrogen gas loses two electrons, and by so doing is oxidized to 2+ + hydrogen ions. Mg (aq) + H2(g) = Mg(s) + 2H (aq) In a reaction, the oxidation of one species must be accompanied by a corresponding reduction of another species involved in the reaction. For the following reactions, say which species are being oxidized and which are being reduced: 2+ 3+ 4+ 2+ (i) Sn (aq) + 2Fe (aq) = Sn (aq) + 2Fe (aq) + 2+ (ii) Mg(s) + 2Ag (aq) = Mg (aq) + 2Ag(s) + 2+ (iii) Zn(s) + 2H (aq) = Zn (aq) + H2(g) In an organic chemistry context an oxidation reaction is one that involves the addition of oxygen atoms to, or the removal of hydrogen atoms from, a particular compound. A reduction reaction is the opposite of oxidation, in that it involves the addition of hydrogen atoms to, or the removal of oxygen atoms from, a compound. Question 25 Many reactions of organic molecules can be predicted from a knowledge of the functional groups they contain. Match the name of the functional group with the chemical representations below. (a) ester OH (b) carboxylic acid R NH 2 X (c) aromatic (d) amino acid O C C R1 C (e) alkene OH (f) amide O (g) haloalkane (h) alcohol (i) amine R O O C H2N NH 2 R R1 C OH C OR 2 The symbols R, R1 and R2 are used to represent different hydrocarbon groups, or the rest of the molecule. 10 4 Other skills You will find it useful to have acquired, or begun to acquire, the following skills. Basic study skills: organising the time for your studies; learning to pace your study; effective reading to identify and extract relevant information from irrelevant or redundant material; and retrieving data from scientific texts and accounts. Writing skills: the ability to write coherently; structuring and presenting arguments in a logical sequence; writing a scientific account with appropriate diagrams. Problem-solving skills: the ability to solve problems using given evidence (including negative evidence), and using more than one source of information. 5 Answers to self-assessment test 3.1 Mathematics Question 1 (a) -8776 (b) -14 (c) 42 (8 + 6 = 14, 5 − 2 = 3, 14 × 3 = 42) (d) x = 18.5% 15 × 100% = 0.1852 × 100% = 18.52% x = 81 Question 2 3 3 (a) 1400 cm ; (b) 0.63 m . 3 The answer to (a) is 200 cm × 8 cm × 0.90 cm = 1440 cm . To two significant 3 figures, this is 1400 cm . 3 3 Similarly in (b), 0.87 m × 0.09 m × 8.0 m = 0.6264 m , which is 0.63 m when expressed as two significant figures. Question 3 (a) Reading off the plot, the temperature at 300 m is between 18.0 and 18.5 °C. (b) Reading off the plot, the temperature at the surface is 20 °C and the temperature at 1 km (1000 m) is 14 °C. You would therefore expect the temperature to drop by 20 – 14 = 6 °C. Question 4 15.2 mm 22.4 + 13.5 + 12.6 + 23.3 + 4.0 = 15.2 5 11 Question 5 (d) 524 m V = = 3 4 3 π5 3 4 π (125 ) 3 = 523.60, which is the same as 524 to three significant figures Question 6 50 mg m −3 Question 7 g= h+ f k Question 8 4 (a) 1.3 × 10 (b) 1996 3 −1 (c) (+) 1.1 × 10 cases y Question 9 (a) Conventionally this is written as temperature/°C (b) (i) Distance from the epicentre is the independent variable. (ii) 28.5 s (iii) The line is the straight line that best fits all of the data plotted. The points plotted show that although the wave has travelled at a fairly constant speed (hence an almost straight-line graph), at certain times the seismic wave has travelled slightly faster or slightly slower than the mean, i.e. at 25 seconds it has travelled slightly further than expected and at 35 seconds it has travelled slightly less far than expected. (c) The gradient of a straight-line graph is calculated by dividing the ‘rise’ by the ‘run’: For example: y2 − y1 x2 − x1 = 37 − 2 = 0.185 s/km 200 − 0 = 0.185 s/km, which is the same as 0.19 to 2 significant figures Where y relates to the y-axis and x relates to the x-axis. Question 10 –7 1.5 × 10 m The superscript ‘–7’ shows how many times 1.5 has been divided by 10. 12 Question 11 (d) 283.15 K The relationship is that temperature in Kelvin (Tk) is equal to temperature in Celsius (Tc) plus 273.15. That is: Tk = Tc + 273.15 Therefore, for a temperature in Celsius (Tc) of 10 °C: Tk = 10 + 273.15 Tk = 283.15 Question 12 (b) 350 –2 3.5 × 10 particles m –2 3.5 × 10 –3 3 × 104 m = 2 × 104 particles = 3.5 × 10 particles = 350 particles. 3.2 Biology Question 13 Use the list of words below to fill in the gaps in the following passage. All living cells are surrounded by a selectively permeable cell membrane. Most cells in eukaryotic organisms possess an organelle called the nucleus in which are located the chromosomes that carry most of the genetic information of the organism. These structures consist of a long double-stranded molecule called deoxyribonucleic acid (abbreviated to DNA) and various protein molecules. In prokaryotic organisms (such as bacteria) the circular molecules that carry the genetic information lie naked in the cytoplasm. Bacteria and viruses which infect humans are known as pathogens. The immune system produces antibodies, which try and eliminate invading organisms. Antibodies bind tightly and specifically with antigens to produce a complex which can be removed by the immune system. The biochemical processes in the body responsible for metabolism are mediated by proteins called enzymes. These are very specific and bind compounds called substrates. cell membrane, chromosomes, cytoplasm, deoxyribonucleic acid, DNA, eukaryotic, nucleus, prokaryotic, protein, pathogens; antibodies, antigens, metabolism, epitopes; nucleotides; enzymes; particles, substrates. Question 14 The two wrong statements are (a) and (e). Meiosis and not mitosis is the type of cell division that gives rise to gametes. Chromosomes are made mostly of DNA and not protein, although there are proteins called histones around which the DNA is wrapped. Question 15 The two wrong statements are (a) and (d). A, C, G and T are DNA nucleotides; in RNA, T is replaced by U (uracil). There are 23 pairs, or 46 chromosomes in each cell in our bodies, apart from egg and sperm cells which have 23 chromosomes. 13 3.3 Earth Sciences Question 16 The two wrong statements are (c) and (d). The age of the Earth is 4.567 billion years. The more rapidly magma cools, the smaller the resulting crystals as the crystals do not have time to grow. 3.4 Physics and Astronomy Question 17 The two wrong statements are (b) and (c). Comets do orbit the Sun. When meteoroids, which are relatively small stony and/or metallic bodies orbiting the Sun, enter the Earth’s atmosphere they heat up and become visible meteors (or ‘shooting stars’). Meteorites are meteoroids that reach the Earth’s surface. Question 18 The two wrong statements are (c) and (d). A photon is emitted when an atom undergoes a transition from one energy state to a lower energy state. An atom in its ground state has its minimum possible energy. 3.5 Chemistry Question 19 The correct answer is (b) Question 20 This is the complete table: Element Al C Na Si Ca O S Fe Mg Symbol aluminium carbon sodium silicon calcium oxygen sulfur iron magnesium Question 21 A chemical element is a substance that consists of one type of atom that has a unique atomic number corresponding to the number of positively charged protons in its nucleus. A neutral atom has the same number of negatively charged electrons. Atomic nuclei also contain varying numbers of uncharged neutrons. Atoms with the same numbers of protons and neutrons belong to the same isotope of an element. The total number of protons and neutrons (which together are called nucleons) in an atom gives its mass number. A positive ion is created 14 by the loss of one or more electrons from a neutral atom. If an atom should gain one or more electrons it becomes a negative ion. [Although the last two sentences could be exchanged, where the electrons might be gained from to create a negative ion is not particularly relevant.] Question 22 CH4 + (1 x C, 4 x H) 2O2 = (4 x O) CO2 + (1 x C, 2 x O) 2H2O (1 x C, 2 x O) 1xC 1xC 4xH 4xH 4xO 4xO Question 23 The two wrong statements are (c) and (e). The more acidic a solution, the lower its pH (in particular, the pH of acidic solutions is below 7 and that of alkaline solutions is above 7). When CO2 dissolves in water, carbonic acid is formed + 2− (CO2 + H2O → 2H + CO3 ) which makes the water more acidic. Question 24 (i) Tin is oxidized from valency +2 to valency +4; iron is reduced from valency +3 to valency +2. (ii) Magnesium is oxidized from valency 0 to valency +2; silver is reduced from valency +1 to valency 0. (iii) Zinc is oxidized from valency 0 to valency +2; hydrogen is reduced from valency +1 to valency 0. Question 25 a) ester O R1 C OR 2 b) carboxylic acid O R1 C OH c) aromatic 15 d) amino acid O H2N R C OH e) alkene C C f) amide O R C NH 2 g) haloalkane R X h) alcohol OH i) amine NH 2 6 (X= F, Cl, Br or I) If more preparation is needed before studying S240? If you had trouble correctly answering more than 50% of the questions in Section 3 or were unfamiliar with more than a few of the technical terms used in the questions, then you should probably formally study the Open University’s main Level 1 science module (S104 Exploring science) before embarking on S240. If you had difficulty mainly with the maths then you should probably formally study the Open University’s main Level 1 science short module (S151 Maths for science) either before embarking on S240 or alongside. If you had trouble with some of the science disciplines and answered between 50-70% of the questions correctly, then you will probably be ready to study S240, however we suggest you read the S240 Primer in the 2 weeks prior to the module start date (it will be available to you on the module website once you have registered for S240). Alternatively, if you have previously studied S104 (or S100– S103), or equivalent material elsewhere, it should be sufficient to just re-read the relevant material before beginning S240. The Open University offers a number of Science Short Modules on a range of topics, such as Science starts here (S154) and Elements of forensic science (S187). Not only do these modules cover particular subject matter, they also serve as useful introductions to distance education for students who are new to Open University study. 16 7 Further reading If you find yourself well-prepared to study S240 both scientifically and mathematically, then it would be useful to develop the habit of reading popular science periodicals – such as New Scientist and Scientific American – regularly and also looking to see how science is reported in the more serious newspapers. You will find that many of the scientific topics covered in S240 frequently come up in these publications. There are also many popular books on aspects of science relevant to S240. If there is sufficient time before S240 begins, then you might also consider studying a Science Short Module on a topic that interests you, or from the list in Section 2. 8 Your score sheet Subject Question Maths 1 I answered this well 2 3 4 5 6 7 8 9 10 11 12 Biology 13 14 15 Earth Science 16 Physics & Astronomy 17 18 Chemistry 19 20 21 22 23 24 25 17 I need to revise this I didn’t do well on this