All Key 6 Markers Flashcards
(14 cards)
Explain Newton’s Second Law and how it is tested in the core practical.
Newton’s Second Law states that force = mass × acceleration (F = ma). A trolley is pulled by a hanging mass via a pulley. Light gates measure the acceleration of the trolley. Total mass is kept constant when varying force. Acceleration is directly proportional to force. Results confirm the relationship F = ma.
Describe how extension of a spring depends on the force applied, and how it is investigated.
Hooke’s Law: extension is directly proportional to force until the spring’s limit. Hang weights from a spring and measure extension using a ruler. Record force (weight = mass × gravity) and extension for each load. Plot a force vs. extension graph — linear up to elastic limit. Beyond elastic limit, spring is permanently deformed. This practical demonstrates elastic behaviour and Hooke’s Law.
Describe how to determine the density of regular and irregular solids and liquids.
Measure mass using a balance. For regular solids: measure dimensions (length × width × height) to calculate volume. For irregular solids: use a displacement can or measuring cylinder to find volume. For liquids: measure volume in a measuring cylinder, mass with a balance. Use the formula: density = mass ÷ volume. Repeat and average results to improve accuracy.
Describe how to investigate specific heat capacity using a heater and block.
Use a metal block with two holes — one for a heater, one for a thermometer. Measure the block’s mass using a balance. Use a joulemeter to record energy input, and a thermometer to measure temperature change. Insulate the block to reduce energy losses. Use E = mcΔT to calculate specific heat capacity. Rearranging allows you to solve for c (SHC).
Describe how to investigate the resistance of different components in a circuit.
Set up a circuit with an ammeter, voltmeter, and component (resistor, bulb, or diode). Use a variable resistor to change current. Record voltage and current at several values. Plot I-V graphs for each component. Resistor: straight line (constant resistance). Filament bulb: curve due to increasing temperature; diode: current flows one way only.
Describe the wave practicals using a ripple tank and a spring.
In a ripple tank: use a vibrating dipper to produce water waves. Measure wavelength using a strobe lamp and ruler. Count frequency using a timer or slow-motion video. Use wave speed = frequency × wavelength. For springs: use a slinky to create longitudinal and transverse waves. Measure wavelength and frequency to calculate speed.
Describe how to investigate the refraction of light through a transparent block.
Place a glass block on paper and shine a light ray at an angle using a ray box. Draw the outline of the block and trace the incident and emergent rays. Measure angle of incidence and refraction with a protractor. Repeat with different materials or angles. Ray bends towards the normal when entering a more optically dense medium. This shows refraction due to change in wave speed.
Describe how to investigate thermal insulation of different materials.
Wrap boiling water in containers with different insulating materials. Use a thermometer to record temperature every minute for 10+ minutes. Keep starting temperature, water volume, and environment constant. Plot cooling curves (temperature vs. time). Compare temperature loss for each material. The best insulator is the one with the slowest temperature drop.
Describe how stopping distance is affected by various factors.
Stopping distance = thinking distance + braking distance. Thinking distance increases with higher speed, tiredness, drugs, and distractions. Braking distance increases with speed, wet/icy roads, poor brakes/tyres. Doubling speed quadruples braking distance (due to KE = ½mv²). Greater vehicle mass also increases braking distance. Safe driving depends on understanding and reducing both components.
Explain how energy is transferred, calculated, and how to improve efficiency.
Energy can be transferred mechanically, electrically, by heating or radiation. Work done = force × distance (W = F × d). Power = work done ÷ time (P = W ÷ t). Efficiency = (useful energy ÷ total input energy) × 100. Reduce waste by using insulation, lubrication, streamlining. Sankey diagrams show input, useful, and wasted energy visually.
Compare series and parallel circuits and their practical uses.
In series: current same everywhere; voltage shared. In parallel: voltage same; current splits between branches. Resistance adds in series; decreases in parallel. Series: if one component fails, circuit breaks. Parallel: independent operation — used in households. Practical understanding helps design safe and effective electrical systems.
Describe how radioactive half-life works and how it’s used.
Half-life = time for half the radioactive nuclei to decay. It measures how quickly activity drops. Decay is random but predictable over large samples. Used in carbon dating, nuclear medicine, and safety planning. Short half-lives are used in medical tracers to limit exposure. Long half-lives are used in long-term sources but require safe storage.
Explain the life cycle of a star like our Sun.
Stars form from clouds of dust and gas (nebula). Gravity pulls matter together to form a protostar. Nuclear fusion starts — becomes a main sequence star. After hydrogen runs out, expands into a red giant. Outer layers are shed; core becomes a white dwarf. White dwarf cools over time — no more fusion occurs.
Explain how electromagnetic waves are used and their dangers.
Radio: communication (safe, low energy). Microwaves: cooking, satellites (can heat tissue). Infrared: heaters, night vision (skin burns in excess). UV: sterilisation, sunbeds (can cause skin cancer). X-rays: medical imaging (ionising, risk to cells). Gamma: cancer treatment, sterilisation (most penetrating, highly ionising).
