Free ICAS Science Exam Flashcards

A rain gauge collects rainfall. The depth is commonly reported in millimetres; 1 millimetre of rain is equivalent to 1 litre of water spread over 1 square metre.

Place your eye level with the liquid surface and read the bottom of water's concave meniscus against the scale. Looking from above or below creates parallax error.

Use the same instrument, units, body landmarks, alignment, and measuring method each time. A written rule such as nose tip to tail base prevents changes in technique from looking like growth.

Connect an ammeter in series so the circuit current passes through it. Connect a voltmeter in parallel across the component whose potential difference is being measured.

With a constant contour interval, closely spaced lines show a steep slope and widely spaced lines show a gentle slope. The line labels give elevation, while spacing shows rate of elevation change.

Measure its mass and volume, then calculate density = mass ÷ volume. Keep the units compatible, such as grams and cubic centimetres, before comparing materials.

Use actual size = image size ÷ magnification. Convert both lengths to the same unit first; otherwise the numerical answer will be wrong even if the formula is correct.

Accuracy is closeness to the accepted or true value. Precision is closeness among repeated measurements. Results can be tightly grouped yet inaccurate if a systematic error shifts them all.

Apply the stated scale to the measured drawing distance, then convert units. For a 1:50,000 map, 1 centimetre on the map represents 50,000 centimetres, or 500 metres, in reality.

The smallest reliable increment limits resolution. Extra decimal places imply information that was never observed, so a result should be recorded only to a precision justified by the scale or display.

Read the title, variable on each axis, units, scale intervals, and legend. A rising line means an increase only after the axes and direction of time have been confirmed.

It points in the direction of energy transfer, from the organism being eaten to the consumer. Thus grass → rabbit means energy moves from grass to rabbit.

Calculate a rate, such as mass absorbed per minute, using change ÷ time. Comparing raw changes alone can be misleading when the observation periods differ.

Slope represents speed: change in distance divided by change in time. A steeper straight section means greater speed, and a horizontal section means the object is stationary.

A correlation shows that two measured variables vary together, but it does not rule out other explanations or establish a mechanism. Additional evidence and controlled reasoning are needed for a causal conclusion.

Start at the first pair of contrasting statements, choose the one matching the observed feature, and follow its direction. Continue making one two-way choice at a time until an identification is reached.

Series components lie on one unbranched current path. Parallel components lie on separate branches connected across the same two points, so more than one current path exists.

During a phase change at constant pressure, added energy can separate or rearrange particles rather than raise temperature. A plateau can therefore mark melting or boiling until the phase change is complete.

In an undisturbed sequence, lower sedimentary layers are generally older than upper ones. A fault or intrusion is younger than any layer it cuts, allowing an event order without calculating numerical ages.

They show a defined measure of variation or uncertainty, but their meaning depends on whether they represent range, standard deviation, confidence interval, or something else. Overlap alone is not a universal test of statistical significance.

The shadow usually becomes larger because the object blocks a greater spread of diverging rays. The prediction assumes the object and screen remain fixed and the source is not perfectly parallel.

Ignoring effects such as trapped air or surface tension, an object floats if its average density is less than the liquid's density and sinks if its average density is greater.

Its prey may initially increase because predation pressure falls. This is a conditional prediction: food, disease, competition, and other predators can change the actual outcome.

Uncertainty grows when the prediction extends far beyond the observed time range or when conditions can change. A conclusion should state that limit instead of assuming the recent trend continues indefinitely.

Total resistance increases, so circuit current decreases and the identical bulbs are dimmer. This prediction assumes the source voltage and bulb properties stay approximately constant.

A chemical change occurred. Gas, colour, light, precipitate, or temperature change may support that conclusion, but each observation should be checked against possible physical explanations.

As the resource becomes scarce, survival or reproduction is constrained, so growth slows or reverses. The conclusion should identify evidence for the particular limiting factor rather than assume which resource is responsible.

Divergent boundaries create new crust or rifts, convergent boundaries produce subduction, trenches, mountains, or collision zones, and transform boundaries commonly generate earthquakes as plates slide past.

At the highest point, gravitational potential energy is greatest and speed is momentarily zero. At the lowest point, kinetic energy is greatest. In a real pendulum, some mechanical energy transfers to heat and sound.

Total mass should remain constant because atoms are rearranged rather than created or destroyed. An apparent change suggests measurement uncertainty, leakage, or an uncounted transfer rather than failure of mass conservation.

Change the slope angle, apply the same amount and rate of water, and measure soil lost or sediment collected. Keep soil type, starting mass, tray area, vegetation cover, and trial time constant.

Use equal-sized or equal-mass samples, expose each to the same liquid under the same conditions, and measure liquid retained. Repeating trials helps separate a real material difference from random variation.

The control shows growth under the same conditions without the treatment. Comparing it with fertilized groups helps attribute any difference to fertilizer rather than light, water, time, or normal growth.

Change length systematically, measure the time for several swings, divide to find one period, and repeat. Keep bob mass and release angle constant so length is the intended independent variable.

Weather varies across time and space. Broader sampling reduces the risk that one unusual moment or site is treated as representative of the whole period or area.

Change only the solvent temperature and measure a defined dissolving time. Keep solute mass and particle size, solvent volume, container, and stirring method constant, and repeat each temperature.

Random placement reduces selection bias, giving every location a defined chance of sampling. Enough representative quadrats are still needed because a few random samples can miss natural variation.

Check the method, instrument, and recording for a cause; do not delete the value merely because it is inconvenient. Repeat if possible, report the outlier transparently, and justify any exclusion rule.

A hypothesis proposes an explanatory relationship, such as darker surfaces absorb more solar energy. A prediction states the expected observation if it is correct, such as the dark sample showing a larger temperature rise.

Change wire length and measure resistance while keeping material, cross-sectional area, and temperature constant. Temperature matters because heating can alter resistance and confound the effect of length.

Non-living things can move, while some living things show little visible movement. Classification should use a combination of life processes such as cellular organization, energy use, growth, response, reproduction, and waste removal.

Low water permeability is essential, while flexibility, strength, mass, breathability, durability, and cost may also matter. The best choice depends on balancing the stated design criteria and constraints.

Each pair of meshing external gears turns in opposite directions. Therefore two gears turn oppositely, while the first and third gears in a three-gear train turn in the same direction.

A rock can follow several pathways: weathering and lithification form sedimentary rock, heat and pressure form metamorphic rock, melting makes magma, and cooling forms igneous rock. Conditions determine which path occurs.

Its biconcave shape provides a large surface-area-to-volume ratio and a short diffusion path. In mammals, loss of a nucleus leaves more room for haemoglobin, while flexibility helps it pass through narrow capillaries.

Heating makes particles vibrate more energetically, increasing their average separation slightly while their basic arrangement remains. The particles themselves do not simply grow larger.

A sound comparison also considers reliability, output, storage, land and material use, emissions across the life cycle, ecological effects, cost, and local conditions. Different criteria can support different choices.

First convert to compatible units, then use average speed = total distance ÷ total time. For metres per second, use metres and seconds; for kilometres per hour, use kilometres and hours.

Marked individuals must remix with the population, marks must remain detectable and not affect survival or capture, and births, deaths, immigration, and emigration should be negligible during sampling. Violations can bias the estimate N ≈ (first marked × second catch) ÷ marked recaptures.

They give the fixed whole-number ratio of atoms in one formula unit or molecule. H₂O has two hydrogen atoms per oxygen atom, while H₂O₂ has a different ratio and is therefore a different substance.