13.1 Tactics for Stimulus-Based Questions

13.1 Tactics for Stimulus-Based Questions

By exam day, you know what ICAS Science is and you have practised the five skill areas. This chapter is about execution: what your eyes and hands actually do when the paper is in front of you. Almost every ICAS item is built from the same three parts, and knowing that anatomy cold is the first tactic.

The Anatomy of an ICAS Item

1. The stimulus — a diagram, graph, table, map, photograph or short passage describing an experiment or situation.
2. The question — one sentence (occasionally two) stating exactly what is asked.
3. The options — four choices in a multiple-choice item, or targets in a technology-enhanced item.

The trap is to treat these as one blur. They are three separate jobs, and strong students do them in three separate passes.

The Three-Pass Reading Method

• Pass 1 — Skim the stimulus (10-15 seconds). Do not study it yet. Just identify its shape: "This is a line graph of temperature over a week" or "This is a results table comparing four fertilisers." Note the title, the axis or column labels, and the units. Skimming first means you are never reading data without knowing what kind of data it is.
• Pass 2 — Read the question (carefully, every word). Now you know exactly which corner of the stimulus matters. A question asking for the highest value sends you somewhere different from one asking when the value changed fastest. Underline the key word in your mind: highest, first, best explanation, most likely.
• Pass 3 — Return to the stimulus for the evidence. Only now do you read precisely: the exact bar height, the exact table cell, the exact labelled part of the diagram. Answer from what the display actually shows.

Why not just read everything once, slowly? Because a slow single read mixes the jobs up — students absorb every detail of the stimulus before knowing what is asked, then answer from a general impression. The three-pass method front-loads the question so the final read is targeted.

When the Stimulus Contradicts What You Assumed

Sometimes a stimulus describes something that clashes with what you remember from class — a plant that grew well in the dark in this experiment, a material that floats when you expected it to sink. The rule is simple: the stimulus wins. ICAS is measuring whether you can reason from presented evidence, and options are written so that the student who answers from the page beats the student who answers from memory. If the results table says the shaded plant grew taller, then for this question the shaded plant grew taller — your job is to explain or use that result, not to correct it.

Multi-Question Stimuli

Frequently one stimulus serves two or three questions in a row. Handle these with two habits:

• Treat each question as independent. A shaky answer on the first question of a cluster tells you nothing about the second. The writers deliberately build clusters so each item stands alone.
• Go back to the display fresh every time. Do not answer a detail question from memory of a graph you read two minutes ago — under time pressure, memory invents values. Re-reading takes five seconds and is the cheapest mark-insurance on the paper.

Technology-Enhanced Items: Drag-and-Drop and Hot-Spot

In the online sitting, some items go beyond picking one of four options:

The science does not change — only the way you record the answer. Two warnings for the online format. First, in drag-and-drop ordering tasks (life-cycle stages, steps of an experiment), an early misplacement cascades, so anchor on the one position you are certain of and build outward. Second, hot-spot items punish fast clicking: zoom your attention onto the scale and labels before your cursor goes anywhere near the diagram.

Guessing Strategy: Eliminate, Then Choose

ICAS has no penalty for wrong answers — a blank and a wrong answer score exactly the same. So the rule on exam day is absolute: every question gets an answer. But guessing is a skill, not a coin flip:

1. Eliminate what you can. Even on a hard item, one or two options usually contradict the stimulus or break a basic rule of science. Removing them doubles your odds on what remains.
2. Choose from the survivors using the stimulus. Between two plausible options, the one that matches the displayed evidence wins.
3. Never spend your last guess-time frozen. If elimination gets you nowhere in a reasonable time, pick your best hunch, flag the question if the platform allows, and move on — a flagged guess can be revisited; an unanswerable blank cannot.

Worked Example, End to End

Stimulus (Pass 1 skim): a results table — four identical cups of soil, each given a different amount of water daily, plant height measured after three weeks.

Question (Pass 2): "Which amount of water produced the tallest plant, and what do the results suggest about giving the plant even more water?" Two things are asked — a value and an interpretation.

Evidence (Pass 3): The tallest plant is Cup 3 at 14 cm (40 mL). For the second part, notice Cup 4: doubling the water again made the plant shorter, not taller — the trend turns down. The correct option is the one pairing 40 mL with the idea that beyond a certain point, extra water stops helping (waterlogged soil limits air around the roots). Options pairing "80 mL" with "most water is always best" fail on the table's own numbers.

That is the whole routine — skim, question, evidence — applied in under ninety seconds.