What this tool does
A scaffolded sheet for writing a testable prediction, with IF, THEN and BECAUSE boxes and an optional block underneath for naming the variables in the test.
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IF, THEN, BECAUSE
Three boxes across the page: what you change, what you expect to happen, and why you expect it. Underneath sits a fourth block, which can be turned off, naming the variables in the test.
That is the whole sheet, and its usefulness is entirely in the third box.
The BECAUSE box is the hypothesis
"If I put the plant in the cupboard, then it will grow less" is a prediction. Anybody could make it, and being right about it teaches nothing.
"…because plants need light to make food" is a hypothesis. It commits to a reason, and the reason is the thing the experiment actually tests. If the plant grows less, that explanation survives; if it grows the same, something in the reasoning was wrong, and finding out which part is the interesting bit.
Children left to write a hypothesis on a blank page produce the prediction and stop, every time. Printing the word BECAUSE in a box is a remarkably effective fix for that.
Filling it in before the experiment, in ink
The whole structure collapses if the sheet is completed afterwards, and a fair number of children will do exactly that if the opportunity exists.
Get them written and collected before anything is set up. A hypothesis that turned out wrong, still sitting in the book, is worth more than a correct one written after the fact. Saying so repeatedly is the only thing that makes a class believe it.
The variables block
On by default, and worth leaving on from about Year 5 upward.
Independent is the one thing you change. Dependent is what you measure. Controlled is everything you deliberately keep the same, and it is the box that separates a fair test from an anecdote — the plant in the cupboard needs the same pot, the same soil, the same water and the same start date, or the result means nothing regardless of which way it goes.
Turn the block off for younger children, where IF-THEN-BECAUSE on its own is plenty and the vocabulary would crowd it out.
Setting the sheet up
A title and the variables block on or off. Paper size A4 or US Letter.
Using it with the experiment log
This sheet goes first, then the science experiment log carries the method, the observations and the conclusion. Keeping the hypothesis on its own page makes it harder to quietly revise once the results are in.
Print at 100% on A4 or US Letter.
FAQs
Quick answers
What is the If / Then / Because framework?
A simple sentence scaffold that forces a testable hypothesis: "IF I change X, THEN Y will happen, BECAUSE …". It makes the prediction explicit and its reasoning visible.
What is the variables box for?
Three side-by-side boxes for the independent variable (what I change), the dependent variable (what I measure) and controlled variables (what I keep the same). Toggle it off for simpler lessons.
Is this suitable for primary school?
Yes, upper primary onwards. Younger students can fill in IF / THEN / BECAUSE only; the variables box is optional for older students.
Does it pair with the experiment log?
Yes. Many teachers staple the hypothesis worksheet to the front of the science experiment log so students revisit their prediction after collecting data.
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