Independent, Dependent and Controlled Variables

Lab Brief #2

🎯 Your mission

Run the experiment. Find out what really happens.

⚡ The twist

Nature loves to surprise the careful watcher.

What you'll learn

A fair test changes one independent variable, measures the dependent variable, and holds every other controlled variable fixed. If two things change at once, the result cannot be attributed to either, no matter how large the effect looks. Listing the controlled variables out loud before starting is the step that catches the ones which would otherwise drift by accident — room temperature, the age of the sample, the person taking the reading.

Key words

independent variable
The one variable deliberately changed in an investigation.
controlled variable
A variable deliberately held constant so that any change in the result can be attributed to the independent variable.

Make a hypothesis first

Before you start: write down what you think will happen, and why.

Say your guess out loud — then find out if you were right.

Get ready

🧰 What you need

sugar cubes
granulated sugar
beakers
thermometer
stopwatch
balance

Get ready

⚠️ Safety first

Mop up spills straight away so nobody slips.

Step 1 of 4 · Read

Think about what you just learned: say what "independent variable" and "controlled variable" mean in your own words before you start.

Step 2 of 4 · Do

Design an investigation into how surface area affects dissolving time, writing the independent, dependent and at least five controlled variables before you touch any equipment. Run it, then list any controlled variable that actually drifted.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 3

The variable deliberately changed in an investigation is the:

How sure are you?😐 maybe

Question 2 of 3

If two variables change at once, the result is:

How sure are you?😐 maybe

Question 3 of 3

Listing controlled variables before starting mainly helps you:

How sure are you?😐 maybe

Mind = blown

🔬 The more you look, the more nature shows you.

Nice work!

You got 0 of 3 right.

Next: Random Error Scatters, Systematic Error Shifts All lessons

🎯

Next Smart Experiment

We'll pick an experiment that matches exactly how you're thinking right now.

✨ More to explore

🌍 Where you see this in real life: This shows up in your everyday life more than you'd think.

🏆 Stretch challenge (try it this week): Try one experiment in real life this week — even a tiny one.

👨‍👩‍👧 For the dinner table: “What's the most surprising thing you learned today?”

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Independent, Dependent and Controlled Variables

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Independent, Dependent and Controlled Variables

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