ISAT Science Grade 5 common mistakes
ISAT Science Grade 5 · Understand the traps and how to avoid them.
After stirring sugar or salt into water, the student writes that the solid 'disappeared,' 'melted,' or 'turned into water,' and says the cup now weighs less than it did before.
Dissolving is invisible at the particle level, and everyday talk ('it's gone') supports the idea that matter can vanish. Students have no working model of particles too small to see that still exist and still have mass.
What to do instead
Have students evaporate a salt or sugar solution and recover the solid, and compare total mass before and after dissolving on a balance. Anchor the rule 'dissolving spreads matter out; it does not destroy it,' and require mass evidence in every explanation.
Draws heat-flow arrows from a cold object toward a warm one, or says a sweater 'keeps the cold out' by adding warmth, or that a metal spoon 'makes' the soup hot.
Sensation drives intuition: metal feels cold because heat leaves your hand quickly, so students infer that cold is a substance that travels and that warm clothing supplies heat rather than slowing its loss.
What to do instead
Practise the rule 'heat moves from warmer to cooler, never the reverse,' using safe thermometers to show both objects drifting toward room temperature. Classify a sweater or foam cup as an insulator that slows heat loss from the body, not a heat source.
Says a rolling ball slows down because 'the force ran out' or 'the push got used up,' and claims a wagon needs a constant push to keep moving at a steady speed on a level floor.
Force and motion feel linked in daily life - pushing harder makes things go - so students treat force as a stored quantity carried inside the object rather than an interaction between objects, and they overlook friction.
What to do instead
Have students draw force arrows on a diagram: once the push stops, friction and air resistance point backward and form the unbalanced force that slows the ball. Contrast a prediction for a frictionless surface with what actually happens, and name friction in every stopping explanation.
Draws food-chain arrows pointing from the predator back to the prey (fox to rabbit), reads each arrow as 'is eaten by', and then misidentifies which organism receives the most energy.
Family trees and flowcharts put the source on the left, and 'the fox eats the rabbit' feels like movement toward the eater. Arrow direction is a convention students must be taught, not a pattern they invent.
What to do instead
Teach the arrow as 'energy moves to' and read each link aloud as a sentence: 'grass to rabbit means the energy stored in grass moves into the rabbit.' Trace one sun-to-owl energy path and have students explain why the arrowhead always points toward the eater.
Writes that a plant's food and growing mass come from soil, and that plants 'eat' dirt the way animals eat food; predicts the soil in a pot must lose mass as the plant grows.
Soil and water are visible and plants are rooted in them, while the gases a plant takes from the air are invisible. The visible inputs get credit for growth, and 'food' is assumed to mean something eaten.
What to do instead
Use the classic comparison of a tree grown in a weighed pot where the soil mass barely changes, alongside the statement that plants make their own food from air and water using light energy. Have students sort plant needs into 'matter taken in' versus 'energy from the Sun.'
Explains a trait by need or choice - 'the birds needed to eat hard seeds, so their beaks got stronger' - and says the stronger beak then passes to the chicks.
Purposeful, intentional language fills children's media and everyday speech, and students lack a model of variation plus inheritance across generations, so they collapse evolution into a single lifetime of effort.
What to do instead
Graph beak-size variation within one generation, mark which birds survive when the seed type changes, then track the trait into the next generation. Supply the sentence frame 'Some birds already had ___; those birds survived and reproduced more.'
Chooses 'Earth is closer to the Sun in summer' as the cause of seasons, and when asked about the two hemispheres predicts both are in summer at the same time.
Distance-from-a-heat-source works for campfires and lamps, so closer-means-hotter is a reasonable extrapolation, and exaggerated elliptical-orbit drawings reinforce it. The tilt effect is subtle and hard to feel.
What to do instead
Use a lamp and a tilted globe to show direct versus spread-out sunlight over the same area. Emphasise the counter-evidence: both hemispheres sit at the same distance from the Sun yet experience opposite seasons, and the whole Earth is slightly farther from the Sun during Northern-Hemisphere summer.
Says the Moon's phases are caused by Earth's shadow falling on the Moon, and expects to find a crescent Moon sitting near Earth's shadow in the sky.
A lunar eclipse is the one familiar shadow-on-Moon event, and a crescent genuinely looks like a circle with a bite removed, so shadow reasoning is visually tempting and easy to state.
What to do instead
Run a ball-and-lamp model with the student as Earth, moving the 'Moon' to eight positions and recording how much of the sunlit half faces the observer. Point out that Earth's shadow touches the Moon only at a lunar eclipse, which happens at full Moon, not at every phase.
Treats design constraints as if they were success criteria - calling a paper bridge 'best' because it used only paper clips, or accepting a design that stays within budget but holds no weight.
Both appear in the same design brief and both read as rules, and students have not practised separating 'must work' from 'must stay within limits,' so a single pass-fail judgment replaces scoring on two axes.
What to do instead
Give a two-column brief: 'It succeeds if...' alongside 'It must stay within...'. Score every prototype against both columns and require one trade-off sentence, such as 'This design holds more mass but uses more straws than the limit allows.'
Tests a prototype once, changes several materials at the same time, and announces 'it works' or 'the tall one is best' with no repeated trials and no measured numbers.
Students want an answer quickly and treat variation between trials as noise rather than data, and without a planned comparison routine 'best' quietly becomes personal preference.
What to do instead
Require a written test plan before building: one variable changed, at least three trials, a numbered measurement such as centimetres of span or grams held, and an average. Students record results in a table as they test so the data, not opinion, selects the winner.