BASIC SCIENCE [BSC410S]

Transcription

1 FEEDBACK TUTORIAL LETTER ASSIGNMENT 1 SECOND SEMESTER 2017 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. 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. 1

3 Section A Biology [40] Question amount or quantity of matter amount of space occupied by matter physical property chemical property physical property chemical property it is only a chemical change if a new substance is formed with properties that are different from the substances that combined to form this new substance Solids have rigid, ordered structures, in fixed positions Gas atoms are randomly arranged (far/close describe distance not arrangement) In solids atoms move through vibration only, therefore small thermal expansion while in gases atoms move at high speeds, colliding with container, therefore moderate thermal expansion. (nothing to do with forces) In solids atoms are held tightly together, therefore incompressible while in gases atoms are far apart ie can be compressed. 1.4 Sodium chloride ; NaCl 1.5 Synthesis ; reaction involves a combination of elements to form compounds 1.6 A solute is a substance in a smaller amount, which is dissolved in the solvent and a solvent is the liquid in which the solution is made of and is in a greater amount. Solvent water Solute hydrochloric acid only stating smaller amount or larger amount does not define if the substance is the solute or solvent 1.7 A filtrate is a liquid that passes through the filter paper during filtration whereas a residue is a solid that remains on the filter paper. 1.8 Separating funnel is used to separate two immiscible liquids. (these may include but is not limited to oil and water) Depends on the density (that is why the less dense of the two liquids can float on the more dense liquid) 2

4 Question Absolute zero is defined as the lowers possible temperature. Examples of absolute zero: 0 K ; o C ; o F 2.2 o 9 o 9 o F = C + 32 = = F 5 5 o K = C = = K 2.2 o K = C = = K 9 9 F = C + 32 = = F 5 5 o o o An error is the difference between the accepted/true value and experimental value Significant figure is the number of figures in a value that are known with a degree of accuracy and precision. 2.4 No they are not similar Accuracy refers to how close are measurements to the true value. Precision refers to how close the measurements are to each other x x x ml x 10 3 also x Question All living organisms are made up of cells. The cell is the basic unit of life. 3.2 Unicellular organism: an organism with only one cell is called a unicellular organism Multicellular organism: these are organisms that are made up of more than one cell 3.3 Fish = living thing, as it they able to move, respire/breath, sensitive (respond to stimuli), grow, reproduce, requires nutrition and excrete waste products (meet 7 characteristics of living organisms Rock = non-living, as it does not meet 7 characteristics of living organisms Carolus Linnaeus It is when a name has two parts, a genus and species. 3

5 3.4.3 A common name will vary from country to country and different countries use different languages. The scienctific name will be the same throughout the world Any correct 3 ( each) Fungi are heterotrophs, feed on other matter They lack chlorophyll and therefore cannot make their own food like plants Their cell walls are made up of chitin and not cellulose They have not roots and therefore obtain nutrients from dead or living organic matter. Question 4 Section B Chemistry [40] Angiosperm - Flowering plants, having fruits and seeds formed inside the ovary. Gymnosperms Cone-bearing plants, having no flowers and fruits Deciduous shed off all leaves Evergreen some leaves are always present Self-pollination Pollination takes place on the same plant such that pollen is from the anther to stigma of the same plant. Cross-pollination Pollination takes place on a different plant of the same species such that pollen is from the anther to the stigma of different plant of the same species 4.2 They don t have a backbone keep the inside of their bodies at a constant temperature - generate their own heat when is cooler environment - Cools themselves when in hotter environment Question Habitat - The place where an organism lives Population - All living organisms within an area belonging to the same species (have to specifically mentions same species) Community - All various populations interacting in a particular area Ecosystem - A community of various populations and their abiotic environment The desert plants, because they make their own food Insects, small lizards, and Kangaroo rats each because the only feed on desert plants Hawks and desert foxes 5.3 Competition results when resources such as food, water and living space are not enough for everybody Intraspecific competition Interspecific competition 4

6 5.5.1 Endangered animal; It is about to die out completely/very few left/very low numbers Any correct two - Loss of habitat/loss of habitat/chemical or pollution poisoning Section C Physics [30] Question A scale on any graph should include all measurements/variables of a particular measurement a graph axis is a reference line drawn on a graph, which you can measure from or find values from these variables are what you measure during an experiment and is affected during the experiment intervals are set on axes according to maximum and minimum values and should all be the same through Question Graph title, axes titles and units Car A 0 2 seconds Car A 2 4 seconds Car A 0 2 seconds 7.2 Car A = (0.5 x 2 x 10) + (18 x 2) = = 46 m Car B = (0.5 x 2 x 14) + (14 x 2) = = 42 m 5

7 Question renewable 8.2 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. (a general answer on the generation of hydroelectricity will not be acceptable here, because in most cases a dam wall is built and the generators are inside the dam wall which is not the case at Ruacana) 8.3 boiling water to create steam in order to transport heat energy In the cooling towers Question With reference to the source applying the force, a pulling force attempts to bring the object closer and a pushing force attempts to propel the object further away. 9.2 By subtracting the forces = 50 N south 18 N north Resultant force = = 32 N north Can also write 32 N as the - sign is used to indicate direction South 9.4 When the limit of proportionality is reached, and the spring is stretched further, the shape is permanently changed. 9.5 Limit of proportionality 6