CCSLC Integrated Science cheat sheet

Observation uses the five senses plus instruments; inference is a conclusion drawn from observations, so the same observation can support different inferences.

A hypothesis is a testable prediction written as an if–then statement; a theory is a well-supported explanation, and a law describes a consistent pattern.

Controlled experiment rule: change only the independent variable, measure the dependent variable, and keep all other variables constant.

A control group receives no treatment (or a standard treatment) so the effect of the independent variable can be compared.

Repeat trials and average results to reduce the effect of random error; an outlier is checked, not automatically deleted.

Accuracy is closeness to the true value; precision is closeness of repeated readings to each other. A systematic error shifts all readings the same way.

Mean = sum of values ÷ number of values; median = middle value when ordered; mode = most frequent value.

Reading scales: read at eye level, note the smallest division, and estimate one extra digit; for a liquid meniscus read at the bottom of the curve.

SI base units: metre (length), kilogram (mass), second (time), ampere (current), kelvin (temperature), mole (amount), candela (luminous intensity).

Characteristics of living things: nutrition, respiration, excretion, growth, movement, sensitivity/response, reproduction (often remembered as MRS GREN).

Cell parts: nucleus controls activities, cytoplasm is where reactions occur, cell membrane controls entry and exit; plant cells also have a cellulose cell wall, chloroplasts and a large vacuole.

Photosynthesis: carbon dioxide + water → glucose + oxygen, using light energy trapped by chlorophyll in chloroplasts.

Respiration releases energy from glucose; aerobic respiration uses oxygen and gives carbon dioxide and water, while anaerobic respiration gives less energy.

Food chain arrows show the direction of energy flow; producers are at the base, and energy decreases at each trophic level (only about 10% passes on).

A habitat is where an organism lives; a population is one species in an area; a community is all populations; an ecosystem includes the non-living environment.

Abiotic factors include light, temperature, water, soil pH and oxygen; biotic factors include predators, competitors, disease and food supply.

Adaptations: xerophytes have thick cuticles and reduced leaves; hydrophytes have air spaces; animals in dry regions conserve water and are often nocturnal.

Decomposers such as bacteria and fungi break down dead matter and return nutrients (for example nitrates) to the soil for plants to reuse.

Digestion: mechanical breakdown by teeth and churning, chemical breakdown by enzymes; amylase acts on starch, protease on protein, lipase on fat.

Absorption occurs mainly in the small intestine through villi, which have thin walls, a rich blood supply and a large surface area.

The heart has four chambers; the left ventricle has the thickest wall because it pumps blood at high pressure around the whole body.

Arteries carry blood away from the heart under high pressure, veins carry blood back and have valves, capillaries are one cell thick for exchange.

Breathing mechanics: intercostal muscles and diaphragm contract → volume increases → pressure falls → air enters; exhaled air has more carbon dioxide and less oxygen.

Blood transports oxygen bound to haemoglobin in red cells, nutrients from the gut, carbon dioxide to the lungs and urea to the kidneys.

The nephron filters blood in the kidney; useful substances such as glucose and most water are reabsorbed, and urine contains urea, excess salts and water.

Pathogens: bacteria and fungi can be treated with antibiotics, viruses cannot; vaccination gives immunity by stimulating antibody production.

Health risk factors include smoking, excess alcohol, poor diet, lack of exercise and unprotected exposure to disease vectors such as mosquitoes.

Particle model: solids vibrate in fixed positions, liquids slide past each other but keep a fixed volume, gases move freely and fill the container.

Heating increases particle energy; melting and boiling absorb energy at constant temperature, while condensing and freezing release it.

Diffusion is faster at higher temperature and for lighter particles; it occurs in liquids and gases because particles move randomly.

Elements contain one kind of atom, compounds contain atoms of different elements chemically joined, and mixtures can be separated by physical means.

Separation methods: filtration (insoluble solid from liquid), evaporation (dissolved solid from solution), distillation (solvent from solution), chromatography (dyes).

Atomic structure: protons (positive, in nucleus), neutrons (neutral, in nucleus), electrons (negative, in shells); atomic number = number of protons.

Acids have pH below 7, alkalis above 7, neutral is 7; acid + base → salt + water, and acid + metal carbonate → salt + water + carbon dioxide.

Test for carbon dioxide: turns limewater milky; test for oxygen: relights a glowing splint; test for hydrogen: burns with a 'pop'.

Density = mass ÷ volume; a material floats in a liquid if its density is lower than the liquid's density.

Energy is conserved: it is transferred between stores (kinetic, gravitational potential, elastic, chemical, thermal, nuclear) but never created or destroyed.

Work done = force × distance moved in the direction of the force, measured in joules.

Kinetic energy = ½ × mass × speed²; gravitational potential energy = mass × g × height (g ≈ 10 N/kg).

Power = energy transferred ÷ time, measured in watts; 1 watt = 1 joule per second.

Efficiency = useful output energy ÷ total input energy × 100%; the remainder is usually dissipated as heat to the surroundings.

Conduction transfers energy by particle vibration mainly in solids; convection transfers it by moving fluid currents; radiation needs no medium.

Dark, matt surfaces absorb and emit radiation better than shiny, light surfaces; trapped air is a good insulator because it reduces conduction and convection.

Renewable resources (solar, wind, hydroelectric, geothermal, biomass) are replaced naturally; fossil fuels and nuclear fuel are non-renewable.

Electric current is the rate of flow of charge (I = Q ÷ t); mains electricity is dangerous because of the high voltage and the current it drives through the body.

Speed = distance ÷ time; velocity includes direction; acceleration = change in velocity ÷ time, measured in m/s².

Newton's laws: no resultant force means constant velocity; resultant force causes acceleration (F = m × a); every action has an equal and opposite reaction.

Weight = mass × gravitational field strength; mass in kilograms is unchanged on the Moon, but weight is about one-sixth of that on Earth.

Friction opposes motion and produces heat; it can be reduced with lubricants, smooth surfaces or streamlining.

Pressure = force ÷ area; pressure in a liquid increases with depth, and gases exert pressure from particle collisions with the container.

Moments: moment = force × perpendicular distance from the pivot; a balanced lever has clockwise moment = anticlockwise moment.

Earth rotates on its axis once about every 24 hours, causing day and night; it orbits the Sun once about every 365¼ days, causing the seasons.

The Moon orbits Earth about every 28 days; its phases result from the changing angle between Earth, Moon and Sun, and it causes tides.

The Solar System has eight planets orbiting the Sun; gravity keeps planets in orbit, and the Sun is the main source of energy for Earth.