FEEDBACK TUTORIAL LETTER

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1 FEEDBACK TUTORIAL LETTER 1 st SEMESTER 2017 ASSIGNMENT 1 BASIC SCIENCE BSC410S 1

2 Dear Student Assignment One has been marked and this serves as feedback on the assignment. Individual feedback is already included in you assignment by the tutors that marked your assignment. We hope that the answers contained in this feedback letter will guide you through finding the correct solutions more easily. The course Basic Science consists of three sections, Biology, Chemistry and Physics. These three legs of science are intertwined on so many levels and understanding how rests on many facts and rules. The feedback tutorial letter explains every question and gives the correct answer, as well as elaborate on how to arrive at the correct answer. Study the solutions carefully. If there are still areas that are unclear, please contact the tutors. We would also like to bring under your attention a few tips on answering questions in future assignments and the examination in Basic Science: Make sure you read the question carefully. Make sure you read the WHOLE question. Try to not leave out any questions. You have enough time to answer all the questions. If you do not understand a question, ASK. Leaving out answers without any attempt costs a lot of marks. Make sure you understand what is asked. Discuss, relate, explain, estimate, calculate, determine, describe, verify, list; these are all words that have different meanings. Make sure your answer answers the question. We have found that some of your answers are unnecessarily long. Keep your answers to the point. Also observe the MARK ALLOCATION in order to decide how many facts to include in your answer. Double check your answers. Please use a dictionary, at this stage there is no excuse for spelling mistakes. 2

3 Section A Biology [40] Question 1 [16] 1.1 Classification is the process of grouping things based on their similarities. Binomial Nomenclature is a two-name system, where the first part of name is the genus: first letter always capitalized and the second part of name is the species: first letter always lowercase. Entire name is underlined or italicized 1.2 They do not independently exhibit the characteristics of living organism, meaning without being inside a cell where the replicate, they cannot perform any of the functions that all living organisms perform. Therefore they are considered to be non-living. 1.3 Archaebacteria are prokaryotes and unicellular. Protists are eukaryotes and unicellular and simple multicellular. 1.4 This question many confused dioecious with dicot and monoecious with monocot. If you are unsure look the name/word/phrase up to make sure you answer the question correctly. Dioecious plants - have male (staminate) flowers on one plant, and female (pistillate) flowers on another plant. Monoecious plants - have separate male and female flowers on the same plant 1.5 Gymnosperms seeds are exposed and do not bear flowers or fruits. Angiosperms seeds are covered and bears flowers and fruits 1.6 There are two ways in which living organisms can grow. Think, how can a living thing become bigger. These two ways include increasing the size, all organs, all parts. As well as increasing the number of cells that the organism consist of. Question 2 [14] 2.1 Pollination is needed for the fertilization (reproduction) of plants. 2.2 This answer is in the study guide and the answers for pollination of flowers by different animals/methods are listed clearly. open only during night time when these organisms will be available. white flowers so that they can easily be seen by nocturnal animals. they have a fruity odour which acts as a chemotaxis to attract these animals. 2.3 These two plants have several differences between them. Here are four listed: Monocot Dicot Seeds One cotyledon ½ Two cotyledons ½ 3

4 Flower parts multiples of three ½ multiples of four or live ½ Leaf venation parallel ½ Netted ½ Roots Fibrous roots ½ Tap roots ½ 2.4 You have to clearly state how the plant and the animal benefit from this relationship. The plants benefit by having their seeds distributed away from the parent plant and this would mean that the plant will now grow in other locations. Animals benefit when the seed from the plant that they eat contains food, for example, inside a fleshy fruit. 2.5 Endangered - when there are only a few of one type of animal or plant (species) left in the wild. Extinct - When the whole species has die out completely, no more in existence. Question 3 [10] 3.1 All the members (organisms) of a same species living in one area Competition Commensalism Predation 3.3 Because they consume other organisms in order to live (An organism that does not make its own food). 3.4 They obtain their food either from organic matter or from other living organisms. 3.5 A food chain refers to transfer of energy from producers through herbivores to carnivores in a community. The term food web is broader, as it includes interconnected food chains within a specific ecosystem. 3.6 With this answer you have to be very clear on the difference between these two terms. Yes they both eat dead stuff but because their function in the food chain is different, what they do when they consume their food is important to state. Decomposers break down the nutrients in the dead "stuff" ½ and return it to the soil. Ex. Bacteria/ Fungi ½ Scavengers feed on the tissue of dead organisms ½ (both plants and animals) 4

5 feed on Ex. Vultures/Crows/Shrimp ½ (stating bird will not be correct here as not all birds dead organisms) Section B Chemistry [40] Question 4 [20] There is a difference between sublimation (solid to gas) and reverse sublimation (gas to solid). Thus the correct answer is reverse sublimation ½ eg carbon dioxide to ice ½ Melting and fusion is two completely different processed thus the answer melting OR fusion will be incorrect. Melting is when a substance changes phase while sample remains the same material. During the process of fusion, nuclei combine to form a bigger and heavier nucleus. The correct answer is melting ½ eg ice to water ½ (or any other applicable example) 4.2 An exothermic process is a process whereby heat is given off from the system to the surroundings ie removal of energy from the system to the surroundings. An endothermic process is a process whereby heat is absorbed into the system from the surroundings ie input of energy from the surroundings to the system intensive extensive intensive 4.4 Conditions are what we find outside of an atom. Thus intermolecular forces or phase or volume or mass cannot be conditions. The answers are temperature and pressure of the surroundings. 4.5 Reactants: sodium ½ and chlorine ½ Products: sodium chloride / table salt / NaCl 4.6 Just stating it is a mixture of two substances is not sufficient. Because this can also mean sand and water. A solution is a mixture of specifically a solute and a solvent. Solvent: water Solute: sodium chloride / table salt 4.7 A simple distillation separation method is used to separate a pure solvent from a solution eg water from salt. ½ A fractional distillation method separation method is used to separate one liquid from a mixture of liquids that have different boiling points that are close. eg oxygen and nitrogen from air / the fractions in crude oil ½ 4.8 Sand and water are insoluble ½ therefore the separating method is filtration. 5

6 After a few seconds, the mixture will be poured through the filtration apparatus. ½ Water (filtrate) will be a liquid that passes through the filter paper ½ Sand (residue) will be a solid that remains on the filter paper ½ Question 5 [20] Mass number (A) is the number of protons and neutrons in the nucleus of an element Atoms of an element that have the same number of protons and electrons but different numbers of neutrons OR different mass numbers. 5.2 A Modern Periodic consists of: Periods - horizontal rows of the periodic table (side to side) 1/2 Groups or families - vertical (up and down) column of elements in the periodic table 1/2 5.3 Three main classifications in the periodic table are: Metals - to the left (majority of the elements) Nonmetals - to the right (18 elements) Metalloids - found on a staircase dividing metals and nonmetals (7 elements) C Ar I 15 7 N A complete symbol has the mass number at the top or the proton number at the bottom and the element symbol from the periodic table. Remember that the proton number determines the element Take note of the number of electrons in each shell as well as the total number of electrons. The number of shells are determined by the period (horizontal row) the element is in. The number of electrons in the outer shell is determined by the group (vertical column). The total number of electrons OF AN ATOM are determined by the number of protons. Sulfur 6

neutrons 40 Ca2+ 20 ½ 18 ½ 20 ½ +2 ½ 20 Ne ½ 10 10 ½ 10 ½ 0 ½ The column

7 5.5.1 Oxygen 5.6 Note: Symbol = mass no.elementnet charge Symbol # of protons # electrons # of Net charge neutrons 40 Ca2+ 20 ½ 18 ½ 20 ½ +2 ½ 20 Ne ½ ½ 10 ½ 0 ½ The column for neutrons were missing in the assignment, thus all get the one mark Section C Physics [30] Question 6 [14] 7

8 Any axis title (for the x- and y-axis) consists of two parts: measurement (unit) For example: distance (m) where distance is what you measure and m is the unit of the measurement x-axis: Date (year) ½ y-axis: Mass of Crayfish (ton) ½ x-axis: Time (month) ½ y-axis: Paint color (litres OR kg) ½ 6.2 y-axis: minimum = 5 m/s (speed may start at 12 m/s but is reduced to 5 m/s) maximum = 35 m/s (v = u + at = 5 + (15 x 2) = 35) x-axis: minimum = 0 m/s (time in this case, and time always starts at 0 s) maximum = 30 m/s ( ) 6.3 One mark each for the speed at t = 3 s (13 m/s) t = 5 s (11 m/s) t = 10 s (14 m/s) t = 12 s (18 m/s) Title and unit for both axes Question 7 [16] 8

9 7.1 It is not sufficient to just recite the paragraph in the study guide that summarises hydroelectricity. You have to specifically discuss how electricity is generated at Ruacana waterfalls. And then compare with how it is different with tiday generated electricity. At Ruacana electricity is generated using falling water. The water is directed into large tunnels built within the side of the mountain. The water falls approximately 143 m downwards where it turns the turbines before it leaves the tunnels and rejoins the Kunene River. During the generation of electricity using tides, water flows back and forth through turbines in a horizontal direction as tides move in and out of a lagoon/lake. 7.2 Any correct two Crude oil, natural gas, coal, nuclear energy (it is not sufficient to say fossil fuels, be specific) 7.3 Here is another question in which your answer needs to be specific to what is asked. You have to indicate the two connection methods using the given resistors with the correct symbol. If you do not indicate which connection is series and which is parallel, the examiner of your assignment will assume your first circuit refers to whichever circuit was first in the question. you series: 3 Ω 4 Ω parallel: 4 Ω 3 Ω In this circuit two resistors are connected in parallel. With the switch open the current can still flow through the 2 Ω resistor and thus the total current when the switch is open is 2 Ω. With the switch closed, current now splits up and flows through both resistors. Thus to calculate total resistance you have to use the formula for parallel resistors. Ω = + = = RT This answer you have to convert to obtain R T since the answer 1 3 = R 4 then R T = 4/3 = 1,33 (you have to again indicate which is for the closed circuit and which is for the open circuit) T 9

10 7.4.2 Use the formula for voltage: V = IR and make I (current) the subject of the formula in order to calculate the current. Thus I = V R: Open: Closed: V 12 I = = = 6 A R 2 V 12 I = = = 9,02 A R 1, Q = I x t = 6 x (4x 60 ) = C 10

BASIC SCIENCE [BSC410S]

FEEDBACK TUTORIAL LETTER ASSIGNMENT 1 SECOND SEMESTER 2017 BASIC SCIENCE [BSC410S] 1 Dear Student Assignment one has been marked and this serves as feedback on the assignment. Individual feedback is already