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Figure 1 A graph showing how the surface temperature at Milton Keynes variedover a 24-hour period (14 July 1996).4.2 Working with scientific notationWhen examining the workings of the sensory systems, the stimuli and systemsinvolved often operate over a very large range of values. Scientific data maytherefore be presented in a very wide range of magnitudes of numbers. Forinstance, the light signals detected by the eye can have a frequency of700 000 000 000 000 Hz whilst the part of a nerve responsible for transmittingnerve impulses may only be 0.000002 m in diameter. It is clearly inconvenient toexpress values in such a cumbersome form and therefore you should becomfortable using scientific notation.SAQ 14Give the following values in scientific notation:(a) The speed of light, which is 300000000 m s 1.(b) The diameter of a cell within the nervous system, which is 0.0000033 m.4.3 Using significant figuresBeing precise is very important in scientific measurements, so as well asrounding values, in science it is often appropriate to give a decimal value to anappropriate number of significant figures, which is the number of digits that youcan justify in terms of any uncertainties in the measurement.SAQ 15How many significant figures are there in each of the following measurements:(a) 1.970(b) 0.0012(c) 2.88 106As well as being able to recognise and give values to an appropriate number ofsignificant figures, you should be able to deduce what number is appropriate foryour calculations.7

SAQ 16A nerve is 25 cm long and transmits nerve impulses at a speed of 120 m s–1, howlong will it take for the signal to travel from one end of the nerve to another?Give your answer to an appropriate number of significant figures.4.4 Rearranging equationsIn SD329 we shall not ask you to rearrange equations but your understanding ofthe material will be enhanced if you can follow the stages that are necessary to doso. If you are able to rearrange simple equations then you can feel confident thatyou can cope with the module material.SAQ 17Rearrange the following equations to give an expression for a:(a) c ab(b) c (c)1 a b 1 1 1 a b c4.5 Suggested further resources for Section 4 ‘Maths for Science’ https://www.bbc.co.uk/bitesize/subjects/zqhs34j S155 ‘Good Experiments Guide’ Part 3. 5Northedge, A. et al. (1997) The Sciences Good Study Guide, OpenUniversity Press. ISBN 0 7492 3411 3.Other skillsAs this is Level 3 module, it is expected that you will have achieved a significantdegree of competency in the skills listed below, but that you will refine anddevelop these skills further during your participation in the module.Basic study skillsYou need to have: an ability to organise time for study and to pace it, an ability toanalyse tasks and plan how to tackle them, a willingness to seek help orinformation when appropriate, and to learn from feedback provided.Obtaining, evaluating and interpreting informationYou should be able to: read effectively to distinguish relevant from irrelevant orredundant information and analyse data from scientific text and images; locateand consult a range of online scientific materials appropriate for academic useincluding, but not limited to, the module materials, in order to obtain informationand clarify complex ideas; collate and summarise information in note form;synthesise information, including being able to identify arguments and alternativeinterpretations.8

Writing skillsYou need to be able to present information in a range of formats, e.g. essays,reports, short answers to questions based on information and data abstracted frommodule materials and scientific texts, in each case keeping to the main points,elaborating where necessary and including figures or making references whereappropriate, and ensuring that arguments, ideas and information are presented ina logical sequence.Cognitive skillsInformation processing, including ability to: recognise trends and patterns in data;use evidence to support or refute theories and arguments; assess theadequacy/limitations of explanations; apply knowledge in new contexts,including an ability to recognise associations/relationships, make predictions,extrapolate and interpolate from data.Suggested further reading for Section 5 Northedge, A. et al. (1997) The Sciences Good Study Guide, Open UniversityPress. ISBN 0 7492 3411 3.Some of the skills listed above relate to Information Literacy. SD329 assumesthat you have the skills expected of a student who has completed Level 2 study. Ifyou are unsure of whether you have the skills relating to information literacy youcan check by working through this activity Information Literacy skills: do youhave the Level 2 skills you need? As you work through this 10 minute activity, ifyou identify any skills which you feel you are yet to develop or would like torefresh, you will be directed to associated activities to provide you with trainingin these areas.And finally We hope that this diagnostic booklet has given you a good idea of what priorknowledge you must have before you begin studying SD329. We trust that youhave found it interesting and we look forward to welcoming you to the module.However, if, after working through these notes, you are still unsure about whetheror not SD329 is the right module for you, we advise you to seek further help andadvice from your Learner Support Team (via StudentHome).6Answers to self-assessmentquestionsSAQ 1The completed table is shown below:QuantityUnit nameUnit SymbolLuminous condssElectric currentampereA9

TemperatureKelvinKAmount of substancemolemolSAQ 2(a) The nucleus is the organelle that contains the genetic material of the cell.(b) The mitchondria are often referred to as the power house of the cell becausethey transfer energy into a form that can be used by the rest of the cell.(c) There are in fact two types of endoplasmic reticulum that you may be awareof. The rough endoplasmic reticulum is important for protein synthesis whichtakes place on the ribosomes, whilst the smooth endoplasmic reticulum isimportant for lipid production.SAQ 3The specific molecule acts as a key and binds to a specific receptor binding siteon the surface of the cell, which can be described as the lock. The receptor willonly allow specific molecules to bind to it because of the shape of the bindingsite. Once bound the molecule can set off a chain reaction of events that may alterthe activity of the cell.SAQ 4(a) An element is a substance which cannot be broken down into simplercomponents by a chemical reaction. An example would be carbon or nitrogenbut you could have come up with any example from the periodic table.(b) An atom is a particle consisting of a central nucleus, formed of positivelycharged protons and neutrons (which carry no charge), and surroundingnegatively-charged electrons. Because the number of protons in an atomequals the number of electrons an atom carries no overall charge. Eachelement is composed of a single type of atom. For example, the elementhydrogen consists of hydrogen atoms.(c) A molecule contains two or more identical or dissimilar atoms bondedtogether by covalent bonds. Some common elements exist as diatomicmolecules, e.g. the gases oxygen (O2), hydrogen (H2), nitrogen (N2) andchlorine (Cl2). Water (H2O) is also a molecule.(d) A compound is a substance made up of atoms of different elements combinedin a complex structure, e.g. sodium chloride (NaCl). In each case, thechemical formula of the compound indicates the relative numbers of thedifferent atoms that combine together in its formation.SAQ 5The symbols for calcium and carbon have no subscripts, so there is only one atomof each. However, the symbol for oxygen has the subscript ‘3’, so there are threeatoms of oxygen indicated in the chemical formula. The relative numbers ofatoms indicated by the chemical formula is therefore 1calcium: 1 carbon: 3oxygen.10

SAQ 6Ionic bonding arises as a result of transferring electrons to form positive andnegative ions (thus an ion is basically an atom with a net charge, positive ornegative, resulting from the overall loss or gain of electrons). In contrast,covalent bonding arises when electrons are shared between atoms, formingmolecules.SAQ 7You could have come up with many different examples here. Generally metalssuch as sodium (Na), calcium (Ca), magnesium (Mg) and iron (Fe) form ionicbonds with other atoms by transferring bonding electrons, and so themselvesbecome positively charged ions. The atoms of the element to which the metaltransfers electrons become negatively charged ions, and the resulting moleculesare electrically neutral overall. Sodium chloride (common table salt, NaCl) is anexample of an ionic compound. In contrast, the atoms of the gases hydrogen (H2)and carbon dioxide (CO2) are examples of covalently bonded molecules in whichthe bonding electrons are not transferred, but instead are shared between theatoms.SAQ 8(a) (i) The potassium ion carries only a single positive charge ( ), implying thatonly one electron has been transferred, therefore potassium has a valencyof 1.(ii) The calcium ion carries two positive charges (2 ), implying that twoelectrons have been transferred, therefore calcium has a valency of 2.(b) The charge on the calcium ion is 2 , so two electrons have been transferredto chlorine atoms to form chloride ions. Calcium chloride contains twice asmany chloride ions as calcium ions so each chloride ion must have receivedone of the electrons. Therefore, each chloride ion that is formed carries asingle negative charge, 1 , written as Cl–, and so the valency of chlorine mustbe 1.(c) In CO2, carbon forms two covalent double bonds, so two of its bondingelectrons pair with two electrons on each of the two oxygen atoms. Carbontherefore has a total of four bonding electrons, so it has a valency of 4, whileoxygen has a valency of 2.SAQ 9All except C and F are part of the electromagnetic spectrum. (Sound waves arevibrations of atoms or molecules and alpha particles are helium nuclei emittedfrom some radioactive substances.)SAQ 10In order of increasing frequency: A ‘Radio waves’, D ‘infra red radiation’, E‘visible light’ and B ‘gamma radiation’.11

SAQ 11The negative ions will be attracted towards the positive terminal. The current isequal to the rate of flow of charge so, if the charge on each ion is e and thennumber of ions flowing per second is n, then the current, I , is equal to ne.SAQ 12(a) (volts)-3 (potential difference)(b) (amps)-1 (current)(c) (ohms)-2 (resistance)SAQ 13(a) The maximum temperature (25.2 C) was measured at 18.00 (6.00 p.m.) andthe minimum temperature (15.0 C) was measured at 03.00 (3.00 a.m.).(b) The increase in the temperature between 12.00 and 18.00 hours was 6.0 C(25.2 C 19.2 C). The percentage increase in temperature was therefore6.0/19.2 100% 31% (to two significant figures).SAQ 14(a) 3.0 108 m s–1(b) 3.3 10–6 mSAQ 15(a) four (because the final zero is included when working with significantfigures).(b) two (because the leading zeros are not included when working withsignificant figures).(c) three.SAQ 16The nerve is 25 cm or 0.25 m long. This value is given to 2 significant figures.The speed of transmission is 120 m s 1. This value is also given to 2 significantfigures. This means that the signal can travel 120 m in 1 second so will take0.0020 s to travel the length of the nerve (0.25/120). This value can be given to 2significant figures because the two values used to calculate it are given to 2significant figures and the product of any calculation can only be given to thesame number of significant figures as the least accurate value used in thecalculation (ie the value given to the fewest significant figures).SAQ 17(a) a cb(b) a 1 b or 1 bccc12

(c) a bc b c 13

3.2.2 Suggested further reading for Section 3.2 4 3.3 Chemical concepts 4 3.3.1 Elements, atoms, molecules and compounds 4 3.3.2 Chemical bonding and ions 4 3.2.3 Suggested further reading for Section 3.3 5 3.4 Physics concepts 5 3.4.1 The electromagnetic spectrum 5 3.4.2 Electricity 6 3.4.3 Suggested further reading for Section 3.4 6