ACARA v9 CONTENT DESCRIPTION “pose investigable questions to identify patterns and test relationships and make reasoned predictions”
Builds on earlier wondering about the world. Now an everyday observation is sharpened into an investigable question: you spot a pattern, name the relationship you want to test, and make a prediction with a reason drawn from what light already does.
From a noticed pattern to an investigable question
You step outside in the early morning and your shadow stretches far across the ground. At midday the same shadow shrinks to a short patch near your feet. That is an observation, and the difference between the two times of day is a pattern worth exploring. Not every question about it can be investigated. Asking whether long shadows look spooky is only an opinion. An investigable question instead names a relationship you can measure and test: how does the height of the light in the sky relate to the length of the shadow? To test that fairly you change just one thing at a time, so you can tell what truly caused the change.
Frame the question: change only the light
You saw shadows grow longer when the light sat lower. To test that pattern with a torch, keep everything the same except the one thing you are testing.
You stand a small toy upright on a table and shine a torch at it, then move the torch to change how high or low the light comes from. To test the pattern fairly, hold the other things steady so only the light position differs.
Variable being tested: The height of the light source above the table (this one we change)
You use the same toy standing in the same spot
You keep the torch the same distance from the toy
You measure the shadow on the same flat table each time
Not a fair test yet: more than one thing is changing, so you could not tell which change caused the result. Hold every other variable the same.
Decide what to measure
An investigable question also needs a clear thing to measure, chosen before you begin, so that every trial gives a number to compare. For the shadow test the natural measurement is how long the shadow reaches from the base of the toy. Measure that length the same way every time, from the same starting point, and each light height produces a value you can line up against the others.
Decide what to measure before you start
Lock in the one thing you will record, in the same units, before the first trial, so the light heights can be compared fairly.
To answer whether a lower light makes a longer shadow, you must record the same measurement at every light height, in the same way.
Variable being tested: The height of the light source above the table (this one we change)
The shadow length from the base of the toy, measured in centimetres each trial
Not a fair test yet: more than one thing is changing, so you could not tell which change caused the result. Hold every other variable the same.
Predict from what you have observed
A prediction is more than a wild guess. It says what you expect, and it gives a reason based on a pattern you have already observed. You have seen the shadow grow longer when the light sat lower in the sky. So a reasoned prediction is: when the torch is held very low, close to the table, the shadow will stretch the longest of all. The reason is what light does. A low light skims across the toy at a shallow angle, so the toy blocks light over a long, low streak. The investigation then checks whether that relationship really holds when you measure it.
Look for the pattern in the readings
Once the question is clear and you know what to measure, you take readings and look for a pattern. Suppose you lower the torch step by step, from high above the toy down toward the table, and you measure the shadow each time. A steady pattern would have the shadow grow longer as the light drops lower. Seeing the numbers as a graph makes the trend leap out far more clearly than a list of figures ever could.
See the pattern in the shadow readings
The same toy was lit by a torch lowered step by step toward the table. The shadow length was measured in centimetres. Switch the view to find where the pattern shows most clearly.
As the light drops lower, the shadow grows longer, and the rise is steepest near the bottom. The table lists the numbers, but the line graph shows the climbing relationship at a glance. That is the pattern the investigable question set out to test.
Which predictions are reasoned from the observation?
A prediction is only worth keeping if it follows from what you have actually seen. The observation was that the shadow grows longer as the light is lowered. Sort each statement by whether it is a prediction reasoned from that pattern, or just a guess or an opinion that does not follow from the evidence. Good questioning means telling a reasoned prediction apart from a statement that only sounds related.
Sort the reasoned predictions from the guesses
The observation: the shadow grows longer as the light is lowered. Decide which statements are predictions reasoned from that pattern.
Claim: The lower the light, the longer the shadow.
With the torch held right down near the table, the shadow should stretch the longest yet.
When the torch is raised high overhead, near straight down, the shadow should shrink to its shortest.
A blue torch will surely cast a longer shadow than a white one.
Since each lower position gave a longer shadow, dropping the light a little more should lengthen it again.
Shadows are always longest on a Tuesday.
Decide whether each statement is evidence for the claim, or not.
Why this matters
Every investigation starts with a question you can really test. Learning to spot a pattern in what you observe, to name the relationship behind it, to decide what to measure, and to predict from what you have already seen turns everyday wondering into real science. It is the same first step an astronomer tracking the Sun or an engineer designing a sundial takes before any careful test.
Quick self-check
1. You notice your shadow is short at midday but long in the early morning. Which is an investigable question about this pattern?
2. To test how a torch shone closer or further changes a shadow fairly, what is the one thing you should change?
3. In this shadow test, what is the sensible thing to measure?
4. You have seen that lowering the light makes shadows longer. Which is a reasoned prediction for a torch held very low, near the floor?
5. Your shadow lengths grow steadily as the light is lowered, but one reading is far too short. What should you do with that odd reading?