KEY IDEAS
• A chemical reaction is a process where substances change into new substances.
• Fermentation is a process where microorganisms convert sugars into alcohol or acids.
• Photosynthesis is the process by which green plants convert light energy (sunlight) into chemical energy.
• Respiration is the process by which cells convert glucose into energy.
• Combustion is a reaction involving the burning of fuel to release energy.
• Personal Protective Equipment (PPE) is a gear worn to protect oneself from hazards.
• A chemical is a substance that consists of atoms or molecules with specific properties and characteristics.
• A fire blanket is a safety device designed to extinguish incipient (starting) fires.
• A fire extinguisher is a handheld active fire protection device usually filled with a dry or wet chemical used to extinguish or control small fires.
• A hypothesis is a testable explanation or guesswork designed to guide experimentation and checking information.
• A scientific theory is a well-established explanation for experimental data.
• Scientific method is a way of learning that emphasises observation and experimentation.
• Scientific law -- A relationship between physical observables, often represented by a mathematical formula, tested and developed with numerous and diverse experimental observations.
• Alpha particle is a essentially a helium nucleus.
• Gold foil experiment is an experiment where alpha particles were directed at a thin sheet of gold foil to study atomic structure.
• Deflection is the change in direction of a particle.
• Scattering is the process by which particles are deflected or spread out in different directions after colliding with another particle or barrier.
• Plum pudding model is an early model of atomic structure proposed by J.J. Thomson.
• Nuclear model is the atomic model proposed by Rutherford.
• Atomic spectra are series of coloured bands which are formed when white light passes through a prism.
• Continuous spectrum is a spectrum that has no breaks or gaps between the wavelength range.
• Line spectrum is a spectrum that has discrete lines that can be categorised as excited atoms.
• Radioactivity is the emission of energy from an unstable nucleus, either in terms of particles or electromagnetic radiation.
• Radioisotopes are unstable elements.
• Half-life is the time taken for a radioisotope to reduce the number of unstable nuclei to half of the original value OR the time taken for the Activity of a radioactive substance to reduce to half of the original value.
• Isotopes are atoms with the same number of protons and different numbers of neutrons, e.g. a carbon atom will have 6 protons but can have 6, 7 or 8 neutrons.
• Unstable atom is one that has too much energy or an imbalance of protons and neutrons in its nucleus.