ICAS Science Sample Questions with Worked Solutions
ICAS Science tests scientific skills far more than memorised facts. Most questions hang off a stimulus — a data table, a graph, an experiment or an observation — and ask students to interpret it, reason from it, or spot how to make a test fair. Below are six original, ICAS-style Science questions with full worked solutions. Encourage your child to try each one before reading the answer.
A student counted the oxygen bubbles a water plant made under different brightnesses of light: Dim light → 5 bubbles/min Medium light → 12 bubbles/min Bright light → 20 bubbles/min What do the results show?
- A.The brighter the light, the faster the plant makes oxygen
- B.Brighter light slows the plant down
- C.Light has no effect on the plant
- D.The plant makes oxygen only in the dark
Answer & worked solution
Answer: A) The brighter the light, the faster the plant makes oxygen
As the light gets brighter the bubble rate rises (5 → 12 → 20), so more light means faster photosynthesis. Reading the trend in the table is the key skill here.
A desert lizard is most active at dawn and dusk and shelters under rocks in the middle of the day. The BEST explanation is that it —
- A.shelters to avoid the extreme midday heat
- B.cannot see anything at midday
- C.only eats other lizards
- D.sleeps for several days at a time
Answer & worked solution
Answer: A) shelters to avoid the extreme midday heat
Deserts get dangerously hot at midday. Being active in the cooler dawn and dusk, and sheltering at midday, is an adaptation that avoids overheating and water loss.
Sugar was timed dissolving in water under three conditions: Stirred (cold water) → 20 s Not stirred (cold water) → 55 s Stirred (warm water) → 15 s Which condition dissolved the sugar FASTEST?
- A.Stirred, in warm water
- B.Not stirred, in cold water
- C.Stirred, in cold water
- D.They were all the same
Answer & worked solution
Answer: A) Stirred, in warm water
The shortest time (15 s) was in warm, stirred water. Warmth gives the particles more energy and stirring keeps fresh water around the sugar, so it dissolves fastest.
A stick's shadow was measured through the day: 8 am → long 12 noon → short 4 pm → long The shadow is shortest at noon because the Sun is —
- A.highest in the sky at midday
- B.closest to the Earth at midday
- C.brightest at 8 am
- D.hidden behind cloud at noon
Answer & worked solution
Answer: A) highest in the sky at midday
A high Sun casts a short shadow. At midday the Sun is highest in the sky, so the shadow is shortest; it lengthens as the Sun sits lower in the morning and afternoon.
A trolley was given three different pushes and the distance it travelled was recorded: Small push → 2 m Medium push → 4 m Large push → 6 m What is the relationship between the push and the distance?
- A.A bigger push makes the trolley travel further
- B.A bigger push makes it travel less far
- C.The push has no effect on the distance
- D.The trolley always travels 4 m
Answer & worked solution
Answer: A) A bigger push makes the trolley travel further
As the push (force) increases, the distance increases (2 → 4 → 6 m), so a bigger push sends the trolley further.
To test whether a fertiliser makes plants grow taller, two groups of the same kind of plant are grown with the same water and light — only one group is given the fertiliser. Why must both groups get the SAME water and light?
- A.So any difference in growth is due to the fertiliser (a fair test)
- B.To use up less fertiliser
- C.To make the experiment finish faster
- D.So the plants look tidy
Answer & worked solution
Answer: A) So any difference in growth is due to the fertiliser (a fair test)
In a fair test you change only one thing (here, the fertiliser). Keeping water and light the same means any difference in growth can be linked to the fertiliser, not to something else.
The common thread
Notice that not one question asks for a bare fact. Each gives you something to work from — a table, a set of results, an experiment — and rewards the skill of reading the data and reasoning carefully. That skill focus, spread across the five strands (Scientific Reasoning & Data, Living World, Material World, Earth & Space, Physical World), is what makes ICAS Science distinctive.
Practise more like these
PrepPath offers ICAS-style Science practice for Years 3, 5, 7 and 9 — a timed paper across all five strands, with an estimated award level and a worked explanation for every question. For the bigger picture, read What Is ICAS? and How to Prepare for ICAS Science.
PrepPath is an independent educational platform and is not affiliated with ACARA or the NSW Department of Education. This guide is general information only — always check the official ACARA (nap.edu.au) or NSW Department of Education websites for current dates and rules.