Ukraine 10 клас Natural Sciences (integrated)
Chapters: 6
1. Science: key to the future
Nature of science
- The Scientific Method – The scientific method is the careful way scientists find out how the world works. Observe something, ask a testable question, make a hypothesis (a clear, testable guess), test it with a fair experiment (change one variable, measure one, keep the rest the same), repeat and record data, analyse it, draw a conclusion and share it so others can check. Results that fail the test are useful too: they send you back to a new hypothesis.
2. Particles
Fundamental particles and the Universe · Atoms, isotopes and radioactivity · Radiation and living things
- Particle Physics: Quarks, Leptons and the Standard Model – Particle physics studies the smallest building blocks of matter. Protons and neutrons are made of quarks. Electrons belong to a family called leptons. Every particle has an antiparticle. Particles feel four forces, and three of them are carried by messenger particles called bosons. All of this together is called the Standard Model.
- Radioactivity: Alpha, Beta, Gamma and Half-Life – Some atomic nuclei are unstable. They give out radiation at random to become more stable. This is radioactive decay. Alpha (2 protons + 2 neutrons), beta (a fast electron) and gamma (a wave of energy) are the three main kinds. Half-life is the time for half of the unstable nuclei to decay.
- Mutations – A mutation is a sudden, lasting change in the DNA. Gene (point) mutations change one or a few bases: substitution, insertion or deletion. Insertions and deletions shift the reading frame. Chromosome mutations change big pieces or the number of chromosomes. Mutations happen by chance or because of mutagens such as UV light, X-rays and some chemicals. They can be harmful, neutral or useful, and they are the first source of all genetic variation.
3. Waves
Waves and spectrum · Waves in living things and medicine · Waves in communication
- X-ray Imaging – X-rays are very short-wavelength electromagnetic waves. In an X-ray tube, electrons are sped up by a high voltage and hit a metal target, which gives out X-rays. Different body parts absorb X-rays by different amounts: the intensity falls as I = I₀e^(−μx). Bone absorbs much more than soft tissue, so it shows white on the image. Contrast media, image intensifiers and CT scanners make the pictures clearer and three-dimensional.
- Data Communication Systems – A communication system sends information from a transmitter through a channel to a receiver. The channel can be copper wire, optical fibre or radio waves. To send a message by radio we put it on a fast carrier wave: in AM the carrier's amplitude follows the message, in FM its frequency does. Time-division multiplexing lets many signals share one channel by giving each a short time slot in turn.
4. Substances
Properties and new materials · Methods of studying substances · Waste
- Materials Science: Why Materials Behave the Way They Do – Materials science links what a material is made of inside (atoms, bonds, crystals, grains) to how it behaves (strong, bendy, brittle, light). The four families are metals, polymers, ceramics and composites. We measure properties with tests: tensile test (stress = force ÷ area, strain = extension ÷ length, Young's modulus = stress ÷ strain), hardness tests and impact tests. Heat treatment and alloying change the inside and so the properties. New materials include composites, nanomaterials, smart materials and biomaterials. Chemistry also explains art materials: pigments, binders, ceramics, glass and metals.
- Organic Analysis: Identifying Organic Compounds – Chemists identify an unknown organic compound in two ways. Quick test-tube reactions show which functional group is present: bromine water goes colourless with alkenes, acidified dichromate turns green with primary and secondary alcohols and aldehydes, Tollens' reagent gives a silver mirror with aldehydes, and sodium carbonate fizzes with carboxylic acids. Instruments then confirm it: a mass spectrum gives the relative molecular mass from the molecular ion peak (M⁺), and an infrared spectrum shows which bonds are present.
- Environmental Issues: Causes, Effects and Solutions – Environmental issues are harmful changes to air, water, land, climate and living things, mostly caused by human activity. The big ones are air pollution, water pollution, land pollution and waste, climate change, deforestation and loss of biodiversity, and overuse of resources. They grow with the number of people and how much each person uses (the ecological footprint). We can reduce them with clean energy, saving and recycling, treating waste water, protecting forests and good laws, at home, in the city, in the country and across the world.
5. Mixtures and solutions
Solutions around us · Water
- Solutions: How Things Dissolve and How Much Can Dissolve – A solution is a uniform mixture of a solute dissolved in a solvent. In water (an aqueous solution) the solute breaks into particles too small to see, so it never settles and passes through filter paper. Concentration tells how much solute is present (mass % = solute ÷ solution × 100). Solubility is the most that can dissolve in 100 g of solvent at a given temperature; beyond it the solution is saturated. Evaporation, crystallisation and distillation separate solutions.
6. The cell
Cell and metabolism · Medicines and vaccines · Biotechnology and medicine
- The Cell: Basic Unit of Life – Every living thing is made of cells. Robert Hooke first saw cells in cork in 1665. Cells are prokaryotic (no true nucleus, like bacteria) or eukaryotic (true nucleus). Plant cells have a cell wall, chloroplasts and a big vacuole; animal cells do not. Each organelle has a job. Water enters and leaves cells by osmosis. Cells make new cells by mitosis (growth) and meiosis (sex cells).
- Biotechnology: Principles and Processes (Recombinant DNA Technology) – Genetic engineering means changing the genes of a living thing on purpose. We cut the gene we want with restriction enzymes (molecular scissors), paste it into a carrier DNA called a vector using DNA ligase (molecular glue), put it into a host cell, pick out the cells that took it, and grow them in big tanks (bioreactors) to collect the product. PCR makes millions of copies of a gene, and gel electrophoresis sorts DNA pieces by size.