Skill companion: Planning Reproducible Investigations (Year 8)

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Skill companion · Year 8 Science Inquiryseegongsik /au

Planning Reproducible Investigations: a skill companion

A small set of reusable sheets that grow one inquiry skill: writing a method another group could follow without guessing, stating the assumptions it rests on, and planning for risks to people, care for living things and respect for heritage on Country. Print the scaffolds once and slot them into the science lessons you already teach.

AC9S8I02

plan and conduct reproducible investigations to answer questions and test hypotheses, including identifying variables and assumptions and, as appropriate, recognising and managing risks, considering ethical issues and recognising key considerations regarding heritage sites and artefacts on Country/Place

What a skill companion is

Inquiry skills are not a topic of their own. They grow inside the science units a class teaches all year, from cells and organ systems to plate tectonics, the rock cycle, energy, matter and chemical change. So this pack is not a full term of lessons. It is three reusable scaffolds, a map of where they fit, and a short stand-alone lesson for teaching the skill on its own first.

Start here: five minutes

Read the pairing map on the next page: it shows which scaffold fits which science lesson.
Print the method sheet whenever students plan an investigation, and the risk and respect sheet before any field trip.
Cut out the cards once. They are reused all year, and the blank cards fit any topic.
Open the free interactive unit on your board when you want a worked example of the skill.
Run the one-page mini-lesson first if you want to teach the skill before folding it into a topic.

The step up from Year 7

In Year 7 students planned a fair test and named its risks. In Year 8 the test of a plan is whether a stranger could repeat it: every amount, tool, measuring rule and time is written down, and the plan says out loud what it assumes. Risks are weighed by how likely and how bad they are, and field work plans ahead for Country: places and objects such as middens, grinding grooves and stone arrangements are left undisturbed, and permission comes before access.

On the board

This pack is the printable half of a free interactive unit. On screen, students press “Let it vary” until every line reads “Kept the same” in “Set up the stream investigation as a fair test”, pick each option in “Choose how to fix the sampling sites” to weigh speed against repeatability, and sort actions with “Supports” and “Does not support” in “Judge the plan for the creek investigation”.

seegongsik.com/au/y8/inquiry/AC9S8I02

Aligned to the Australian Curriculum V9 (AC9S8I02). This pack is original material from seegongsik, independently produced and not endorsed by ACARA. Curriculum content descriptors are (c) ACARA, licensed under CC BY 4.0. Free to print and use in class.

Where the skill fitsPairing map

Slot the skill into your science lessons

Every investigation in Year 8 is a chance to plan one that others could repeat. This map shows an investigation in each Year 8 topic, the detail that makes it reproducible, the care it needs, and which scaffold to reach for.

When you teach	An investigation to plan	The detail that makes it reproducible	The care it needs	Scaffold
Cells: the Basic Units of Life (AC9S8U01)	Compare onion skin and pondweed cells under the microscope	The same magnification, and cells counted across one field of view	Iodine stain stings eyes: safety glasses; coverslips are sharp	Method sheet
Cells, Tissues and Organ Systems (AC9S8U02)	Heart rate before and after a minute of stepping	Beats counted for a full 30 s, the same step height and pace for everyone	Anyone may sit out or just measure; results with numbers, not names	Risk and respect sheet, then the cards
Plate Tectonics (AC9S8U03)	Earthquake depths across a boundary, from published records	The data source, the dates and the smallest magnitude written down	Credit the source; take care with recent disasters that hurt people	Method sheet
The Rock Cycle (AC9S8U04)	Pebble size along a creek	Five sites fixed with a tape, twenty pebbles measured across the widest part	Slippery banks; leave grinding grooves, stone tools and arranged stones where they are	Risk and respect sheet
Kinetic and Potential Energy (AC9S8U05)	Bounce height from different drop heights	Height read to the bottom of the ball each time, the same floor, three drops	A partner steadies the chair; no standing on desks	Method sheet, then the cards
Elements, Compounds and Mixtures (AC9S8U06)	Separate sand, salt and iron filings	The same mass of each part, the same volume of water and drying time	Filings in eyes: safety glasses; a hot evaporating dish needs tongs	The mini-lesson, then the method sheet
Physical and Chemical Changes (AC9S8U07)	Temperature drop when bicarbonate of soda meets vinegar	A measured volume of vinegar, a weighed mass of powder, stirred the same way	Safety glasses; wipe spills; rinse the mixture away with water	Method sheet
Any science topic	Any investigation the class plans	Every amount, tool, rule and time written down	People, living things and Country	Method sheet first

The three moves, and the picture that backs each one

When you want a worked example on the board, open the interactive unit and use the picture that matches the move.

Hold every variable but one the same: “Set up the stream investigation as a fair test”.
Weigh a method choice for speed, safety and repeatability: “Choose how to fix the sampling sites”.
Check a plan for reproducibility, safety and respect for Country: “Judge the plan for the creek investigation”.

How the scaffolds build the skill

The method sheet takes a question to variables, assumptions and numbered steps, checks each step against five things a stranger would need, and ends with a swap test. The risk and respect sheet marks a draft field plan, then builds a risk table and a respect plan for the class’s own investigation. The cards sort planning steps into making it reproducible, stating an assumption, and taking care.

Scaffold 1 · Method sheetOne per student

A method another group could follow

NameClassDate

A method is reproducible when a group who has never met you could follow it and get a similar result. Write every step so that nobody has to guess, and say what you are taking to be true.

Our question:

The variables

Independent variable the one I change
Dependent variable the one I measure, and its unit
Controlled variables the ones I keep the same

Assumptions

We assume ...	How we could check it

Method

Could a stranger follow it?

Tick each line when every step of your method passes it.

□ Every amount has a number and a unit.□ Every piece of equipment is named.□ How to measure is defined: what counts, which edge, which reading.□ It says how many trials, and which value is recorded.□ It says exactly where and when.

Swap test

Another pair read our method. They had to guess:

So we added:

Scaffold 2 · Risk and respectOne per student

Take care of people, living things and Country

NameClassDate

A plan that cannot be carried out safely cannot be repeated safely. Before any field trip, check the plan for risks to people, harm to living things, places on Country to leave untouched, and assumptions hiding in the method.

A. Check Class 8C’s draft plan

Question: How does height above the low-tide line affect the number of snails on the rock platform?

Go to the rock platform below the school after lunch on any school day.
Count the snails in a 50 cm square at the water’s edge, halfway up the platform and at the foot of the cliff.
Turn over the loose rocks to find any snails hiding underneath.
Take a bucket of snails back to class to count them properly.
On the way back, collect shells from the old shell heap behind the dunes for the class display.

Look for	Step	The problem	A better step
A risk to people
An ethical issue for living things
A consideration for Country
A hidden assumption

B. Our risk table

Hazard	How likely?	How bad?	What we will do

How likely: unlikely, possible or likely. How bad: minor, moderate or serious. Deal first with anything likely or serious.

C. Our respect plan

Living things
People and their data
Country: places, objects, permission

Scaffold 3 · Planning cards (cut out)Reuse all year

Reproducible, an assumption, or taking care?

Cut out the cards. Lay down the three grey heading cards, then sort the planning steps under them. On a blank card, write a step for your own investigation and swap it with another table to sort.

Makes it reproduciblePins down a detail so another group could repeat the method exactly.Heading

States an assumptionSays what the plan takes to be true without testing it.Heading

Takes careManages a risk to people, or respects living things or Country.Heading

Leave the old shell heap behind the dunes undisturbed, and tell the teacher.Card A

Count the snails where they are, then put every rock back the way it was.Card B

We assume the twenty pebbles we pick up represent the whole site.Card C

We assume yesterday’s rain has not washed new gravel downstream.Card D

Do three trials at each height and record the middle value.Card E

We assume our thermometer reads the same as the other group’s.Card F

Work in pairs and stay on dry, flat rock well back from the waves.Card G

Count the snails inside a 50 cm by 50 cm frame laid at each marked spot.Card H

Write down the date, the time and the tide height for every visit.Card I

We assume the rock type is the same all along the creek.Card J

Mark each sampling site with a numbered peg and record its distance from the gate.Card K

Measure every pebble across its widest part, to the nearest millimetre.Card L

A planning step:

Write your own

A planning step:

Write your own

A planning step:

Write your own

Teacher note: the piles are not the same size. The answer sheet lists which card is which, and why.

Mini-lesson · Teacher planAbout 30 minutes

Write it, swap it, repeat it

Use this stand-alone lesson to teach the skill on its own, before you fold it into a science topic. Pairs write a method for measuring reaction time with a dropped ruler, then swap methods with another pair and follow them to the letter. Every place they have to guess shows a step that is not yet reproducible.

We are learning to

write a method with every amount, tool, measuring rule and number of trials stated,
name an assumption a method rests on, and how to check it,
plan for people: consent, choice and results without names.

Success criteria

Another pair can follow my method without asking me anything.
I can name one assumption in our method and how we could check it.

You need

for each pair: a 30 cm ruler and the method sheet (scaffold 1); the cards from scaffold 3, one set per table,
a reminder that reaction results are about people: ask before recording, write numbers not names, and anyone may sit out and be the recorder instead.

Lesson flow (about 30 minutes)

5 min	Why repeatable? Show the board (see the box). Ask: “If another class tried our method and got a different answer, what might have been different?”
10 min	Write the method Pairs try the ruler drop twice, then write a method on scaffold 1: where the ruler starts, where the fingers wait, what is read, how many trials, which value counts. Ask: “Do you read the ruler at the top of the thumb or the bottom? Does your method say?”
10 min	Swap and follow Pairs swap methods, follow them exactly, and write down every step they had to guess. Compare the results. Ask: “Which missing detail changed the results most?”
5 min	Sort the cards Tables sort the cards under the three heading cards. Ask: “Card F is an assumption. How could we test it before the real investigation?”

Running it shorter? Stop after the swap, and sort the cards in your next science lesson.

On the board

For a worked example, open the unit and press “Let it vary” on each line of “Set up the stream investigation as a fair test” until all four read “Kept the same”. Then pick each option in “Choose how to fix the sampling sites” and compare the upside and downside.

seegongsik.com/au/y8/inquiry/AC9S8I02

Watch for these ideas

A step with no amount, such as “hold the ruler a bit above the hand”.
One trial only, or no rule for which of several trials to record.
Thinking a careful method needs no assumptions.

Make it easier, make it bigger

Easier: give the step starters “Hold the ruler with the 0 cm mark ...”, “The catcher’s finger and thumb are ...” and “Read the ruler at ...”.
Bigger: add a second variable to test later (the other hand, or a sound instead of watching) and say what must stay the same.

Answers and look-fors

The next sheet has the marked draft plan, the card key, a model reproducible method with its assumptions, and a quick three-level guide.

Answers · For the teacherModel responses

Answers and look-fors

Class 8C’s draft plan

Look for	Step	The problem	A better step
A risk to people	1, 2	Any school day may mean a high tide, and a wave at the water’s edge can knock someone over on slippery rock.	Check the tide times and go within an hour of low tide with adults, keep well back from the waves, and wear shoes that grip.
An ethical issue for living things	3, 4	Snails taken away in a bucket may die, and rocks left upside down expose the animals living under them.	Count the snails where they are, turn every rock back the way it was, and take nothing away.
A consideration for Country	5	An old shell heap behind the dunes may be a midden, where Aboriginal people ate shellfish, often over thousands of years; middens are protected.	Leave it undisturbed and take nothing from it; tell the teacher, who can contact the local Aboriginal land council or heritage office.
A hidden assumption	2	The plan assumes the three spots differ only in height, but the water’s edge is also wetter, cooler and washed by waves.	Lay the frame at several spots at each height, and record how wet each spot is and whether it is bare rock or weed.

Step 1 also leaves the method hard to repeat: it gives no date, time or tide, so another class could not visit in the same conditions.

Planning cards

Card	Step	Pile	Why
A	Leave the old shell heap behind the dunes undisturbed, and tell the teacher.	Takes care	It may be a midden, a protected heritage place on Country.
B	Count the snails where they are, then put every rock back the way it was.	Takes care	Respects the animals and their homes.
C	We assume the twenty pebbles we pick up represent the whole site.	States an assumption	Taken as true; picking only big or easy pebbles would break it.
D	We assume yesterday’s rain has not washed new gravel downstream.	States an assumption	Taken as true; fresh gravel could change pebble size for another reason.
E	Do three trials at each height and record the middle value.	Makes it reproducible	Fixes the number of trials and which value counts.
F	We assume our thermometer reads the same as the other group’s.	States an assumption	Taken as true; checking both in the same water would test it.
G	Work in pairs and stay on dry, flat rock well back from the waves.	Takes care	Manages the risk of slipping or being knocked over.
H	Count the snails inside a 50 cm by 50 cm frame laid at each marked spot.	Makes it reproducible	Fixes the size of the area searched.
I	Write down the date, the time and the tide height for every visit.	Makes it reproducible	Lets another group visit in the same conditions.
J	We assume the rock type is the same all along the creek.	States an assumption	Taken as true; a softer rock downstream would wear faster.
K	Mark each sampling site with a numbered peg and record its distance from the gate.	Makes it reproducible	Lets anyone return to the same sites.
L	Measure every pebble across its widest part, to the nearest millimetre.	Makes it reproducible	Defines exactly how width is measured.

Method sheet: a model method at standard

The dropped-ruler test from the mini-lesson, written so a stranger could repeat it.

The dropper holds a 30 cm ruler by the 30 cm end, hanging straight down, with the 0 cm mark level with the top of the catcher’s thumb.
The catcher rests the forearm on the desk with the hand over the edge, finger and thumb 2 cm apart either side of the 0 cm mark, eyes on the mark.
Without warning, within 5 s, the dropper lets go; the catcher pinches the ruler as fast as possible.
Read the ruler at the top of the thumb, to the nearest half centimetre.
Do five catches with the writing hand and record the middle value.

We assume ...	How we could check it
The catcher does not get faster by practising during the five catches.	Compare the first two catches with the last two.
The dropper gives no clue before letting go.	Swap droppers and see whether the results change.

A quick three-level guide

Move	Working towards	At standard	Beyond
Write a reproducible method	steps with no amounts or measuring rules	every amount, tool, rule, number of trials and value recorded is stated	tests the method with a swap and fixes what was guessed
State assumptions	says the method has none	names an assumption the method rests on	says how to check the assumption, or what it would change if false
Plan for risk, ethics and Country	names a hazard without a control	gives a control for each likely or serious hazard, and a step for living things or people	plans for Country before the trip: leaving places and objects alone and asking permission

A student at standard writes a method a stranger could follow, names what it assumes, and plans for people, living things and Country. The skill grows all year, so keep the scaffolds coming back whenever the class plans an investigation.