Science and Technology
विज्ञान तथा प्रविधि · Class 8 · Code BEE-8
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The syllabus asks for
- science and the scientific method
- laboratory work and safety: hazard signs and precautions
- experimental work, recording observations and drawing conclusions
- research work: steps and the research report
- survey: questionnaire, sampling and tabulation
- measurement and units; project work
Key points
- Scientific learning uses observation, test, experiment, research, survey, project work and model making.
- Observation is experiencing an object, event or process carefully with the sense organs; a hand lens or microscope helps. It is the first step of any scientific study.
- A hypothesis is a guess made from observation; a test checks whether it is true. In an experiment only one factor is changed.
- Laboratory rules: apron/lab coat, gloves and goggles with harmful chemicals, no eating, drinking, tasting or direct smelling, no playing, test-tube holder for heating, fumes in a fume hood, wash hands after work.
- Research steps: goal setting → hypothesis → choice of data-collection method → materials → data collection → analysis → conclusion.
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The syllabus asks for
- tools of information and communication technology
- search engine, website and ISP
- social networking sites: uses and risks
- cybercrime, computer code of conduct, cyber law and internet security
- robotics and virtual reality
- artificial intelligence and cloud computing
Key points
- ICT tools create, store, display, send and exchange information: ATM, photocopier, scanner (input, hard → soft copy), printer (output, soft → hard copy), router, Wi-Fi, set-top box.
- ATM input parts: card reader, keypad; output parts: screen, speaker, receipt printer, cash dispenser. Keep the PIN secret.
- A search engine finds web pages by keyword; a website is a collection of web pages with a unique URL; an ISP sells internet access.
- Social media is a strong medium but overuse harms health and invites fake accounts, data leaks and phishing.
- Cybercrime: identity theft, cyber terrorism, cyberbullying, hacking, defamation. Cyber law in Nepal: Electronic Transactions Act, 2063.
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The syllabus asks for
- the cell: plant and animal cells, cell organelles and their functions
- interrelationship among cell, tissue, organ and organ system in the human body
- classification of living beings: five kingdoms and the vertebrate classes
- effects of microorganisms: useful microorganisms and disease-causing microorganisms
- protection of food from microorganisms; vaccination
Key points
- The cell is the structural and functional unit of life (Hooke, 1665).
- Parts: covering (cell wall + membrane), cytoplasm, cell components (organelles + inclusions), nucleus.
- Mitochondria = power house (ATP); chloroplast = photosynthesis; ribosome = protein factory; ER = endoskeleton; Golgi = secretion; lysosome = suicidal bag; nucleus = brain of the cell; human cells have 23 pairs of chromosomes.
- Plant cells have a cell wall, plastids and a large vacuole; animal cells do not.
- Cell → tissue → organ → organ system → body.
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The syllabus asks for
- biodiversity: meaning, levels and importance
- threats to biodiversity and its conservation
- ecosystem, food chain and food web
- sustainable development: meaning, principles and practices
- environment protection and local initiatives
Key points
- Biodiversity = variety of organisms; types: genetic, species and ecosystem diversity (Earth Summit, Rio de Janeiro, 1992).
- Importance: food and livelihood, balanced environment, sustainable resources, ecotourism, adaptation to climate change.
- Nepal: 0.1 % of world area, altitude 59 m – 8848.86 m, 3.2 % of plant and 1.1 % of animal species, 118 ecosystems; spiny babbler is endemic.
- Degradation: overgrazing, pollution, mining, unplanned construction, deforestation, fire, floods, global warming, poaching, invasive species.
- In-situ (national parks, reserves, conservation areas) and ex-situ (zoo, botanical garden, seed bank) conservation.
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The syllabus asks for
- reproduction: asexual and sexual
- sexual reproduction in plants: flower, pollination and fertilisation
- sexual reproduction in animals: internal and external fertilisation
- the seed: structure, germination and dispersal
- growth, nutrition and respiration in living beings
Key points
- Reproduction gives birth to one's own kind; it is asexual (no gametes) or sexual (fusion of gametes).
- Asexual types: fission, budding, fragmentation, regeneration, sporulation, parthenogenesis. Offspring are identical to the parent.
- Vegetative propagation: natural (root, sucker, rhizome, corm, bulb, tuber, aerial stem, bulbil, leaf) and artificial (cutting, layering, gootee, grafting, tissue culture).
- Flower: sepals, petals, stamens (anther + filament), pistil (stigma + style + ovary).
- Pollination: self (autogamy, geitonogamy) and cross (wind, water, insects, birds).
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The syllabus asks for
- motion: distance, displacement, speed, velocity and acceleration
- distance-time and velocity-time graphs
- force and its effects; balanced and unbalanced forces
- Newton's laws of motion in everyday examples
- lever: classes, principle of moments and mechanical advantage
- pressure in solids, liquids and gases; atmospheric pressure and its uses
- Archimedes' principle, upthrust, floatation and density
Key points
- Rest and motion are relative to a reference point. Speed =(d)/(t), velocity =(s)/(t) (m/s); velocity has direction.
- Relative velocity: vA-vB (same direction), vA+vB (opposite).
- Average velocity = total displacement ÷ total time =(u+v)/(2) for steady change.
- Acceleration a=(v-u)/(t) (m/s²); negative acceleration is retardation.
- Slope of d–t graph = speed; slope of v–t graph = acceleration; area under v–t = distance.
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The syllabus asks for
- heat and temperature; thermometers and their scales
- thermal expansion of solids, liquids and gases
- transfer of heat: conduction, convection and radiation
- specific heat capacity and its daily applications
- light: reflection and refraction
- lenses and images; dispersion of light; the human eye and optical instruments
- energy sources, transformation and conservation
Key points
- Energy is the capacity to do work (J); 1 calorie ≈ 4.2 J.
- Heat flows from higher to lower temperature. F=(9)/(5)C+32, K=C+273.
- Conduction (solids, no movement of particles), convection (liquids and gases, movement of particles), radiation (no medium, electromagnetic waves).
- Dark surfaces absorb and emit radiation well; white and shiny surfaces do not.
- Thermos flask: vacuum (no conduction/convection), silvering (no radiation), cork.
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The syllabus asks for
- magnets, magnetic substances and the magnetic field
- terrestrial magnetism and the magnetic compass
- static electricity and electric charge
- electric circuit, current, potential difference and resistance
- Ohm's law and its verification
- household electrification: wiring, fuse, earthing and safety
- electric meter, unit (kWh) and the electricity bill
- magnetic effect of current; electric bell
Key points
- Magnets attract iron, cobalt and nickel; like poles repel, unlike poles attract; a suspended magnet points north–south.
- Natural magnet: lodestone. Artificial: bar, horseshoe, electromagnet.
- Molecular theory (Weber, Ewing): aligned molecular magnets = magnet; random = unmagnetised; all aligned = saturation. Heating, hammering, a.c. and like-pole storage demagnetise.
- Earth is a magnet (molten iron in the outer core). Declination: angle between geographic and magnetic meridians. Dip: angle with the horizontal (0° at magnetic equator, 90° at poles).
- V=IR (Ohm's law); current in A, p.d. in V, resistance in Ω.
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The syllabus asks for
- states of matter and the kinetic idea of particles
- element, compound and mixture; atom and molecule
- physical and chemical change
- solution, solute, solvent; saturated and unsaturated solution
- separation of mixtures: filtration, distillation, sublimation, chromatography
- acids, bases and salts; indicators and pH in daily life
- metals and non-metals; alloys
Key points
- Matter has mass and volume; it exists as solid, liquid and gas.
- Atom: nucleus (protons +1, 1 amu; neutrons 0, 1 amu) and electrons (−1, 1/1837 amu) in shells K, L, M, N with at most 2n^2 electrons.
- Valency = electrons lost, gained or shared to become stable; noble gases have valency 0.
- Criss-cross method gives formulae (MgO, CaCl₂, AlCl₃, NH₃, K₂O).
- Atomic weight = protons + neutrons; molecular weight = sum of atomic weights.
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The syllabus asks for
- water: sources, hardness, purification and water-borne disease
- water pollution and its control
- cement, glass and ceramics
- plastics and polymers: uses and environmental harm
- soap, detergent and fertiliser
- fibre: natural and synthetic
- fuel and combustion; fire safety
Key points
- Hard water has Ca and Mg salts. Temporary (bicarbonates): boiling, Clark's method. Permanent (sulphates, chlorides): washing soda, permutit.
- Water is purified by sedimentation, filtration, boiling, chlorination, SODIS, distillation.
- Acid rain: SO₂ and NOₓ from burning fuels form H₂SO₄ and HNO₃; harms water life, crops, forests and monuments.
- Acid gives H⁺ (sour, blue litmus → red, methyl orange red, phenolphthalein colourless). Base/alkali gives OH⁻ (bitter, soapy, red litmus → blue, methyl orange yellow, phenolphthalein pink).
- Acid + metal → salt + H₂; acid + carbonate → salt + H₂O + CO₂; acid + base → salt + water.
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The syllabus asks for
- minerals: metallic and non-metallic, and their uses
- rocks and the structure of the earth
- origin and age of the earth
- the solar system: planets, satellites, asteroids and comets
- stars, constellations and galaxies
- space exploration and artificial satellites; Nepal in space science
Key points
- Mineral: natural, solid, homogeneous substance of definite composition; types — metallic (ferrous, non-ferrous, precious), non-metallic (gems, non-gems), energy minerals.
- Nepal has more than 60 kinds of minerals; e.g. iron at Phulchoki, limestone at Udayapur, magnesite at Dolakha, uranium in Upper Mustang.
- Earth's layers: crust, mantle, outer core (liquid), inner core (solid). Rocks: igneous, sedimentary, metamorphic.
- Earth is about 4.6 billion years old. Hypotheses: nebular (Kant, Laplace), collision (Buffon), passing-star / planetesimal (Chamberlin–Moulton), tidal (Jeans–Jeffreys).
- Eras: Cryptozoic (simple life), Palaeozoic (invertebrates, fish, amphibians, ferns), Mesozoic (reptiles, dinosaurs, conifers), Cenozoic (mammals, flowering plants, humans).
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Objective questions
Science and Technology: Unit-wise Objective Question Bank
Subjective questions
Science and Technology: Unit-wise Subjective Question Bank
Model sets and predicted questions
Science and Technology: Model Question Sets and Predicted Questions
Exam guide
The Basic Level Examination: Pattern, Grid and Strategy
The paper
Basic Education Examination (BEE), grade 8. The CDC basic-level assessment scheme gives continuous (internal) assessment 50 % weight and the external written paper 50 %; the local level (palika) conducts and marks it. These practice sets are written to a 50-mark written paper of 2 hours unless your palika's grid says otherwise.