1. Variables and Controls Tennessee SPI Objective: Essential Question(s)
SPI 0807.Inq.1C
Controls
Notes
SPI 0807.Inq.1
Variables and Controls
Science
Tennessee SPI Objective:
Design a simple experimental procedure with an identified control and appropriate variables.
Essential Question(s)
1) What are controls in experiments?
2) What is the difference between constants and controls?
I Can Statement
I can identify control trials in a simple experiment.

2. What Are Control Trials? (Also called controls and/or control groups)
A control trial is...
…an experiment separated from the main experiment where the independent variable being tested cannot influence the results.
A control trial is...
…an experiment to verify the results of another experiment
using the same conditions except for one factor or variable.
How to do a control trial:
Just remove the independent variable entirely or replace it with a neutral substitute.

3. Fruity Pebbles Experiment Experiment
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
Experiment
Does eating a sugary cereal make children hyperactive?
Every morning have 3 children eat a bowl of Fruity Pebbles.
Then observe their energy level for the next two hours.
Manipulated/Ind Variable:
-the sugary cereal
Responding/Dep Variable:
-their behavior
This is called the experimental group
Next do a control trial/control group
(see next slide)

4. Fruity Pebbles Experiment (cont. from previous slide)
Manipulated/Ind Variable:
-the sugary cereal
Responding/Dep Variable:
-their behavior
Do a control trial by removing the independent
variable entirely and/or use a neutral substitute.
Option 01: Repeat this experiment exactly except this time don't give the children any cereal at all. Just leave out the independent variable entirely.
Option 02: Repeat this experiment exactly but give them a neutral substitute such as a bowl of cereal that does not contain any sugar.

5. Example: A scientist is conducting an experiment to test how
sunlight affects plant growth.
She places one corn plant 1 meter away from a sunlamp.
She places one corn plant 2 meters away from a sunlamp.
She places one corn plant 3 meters away from a sunlamp.
Corn plant 01
Corn plant 02
Corn plant 03
Ind. variable is the distance from the sunlamp/amount of sunlight.
Dependent variable is how tall the plants grow.
Do a control trial by removing the independent variable
entirely or replace it with a neutral substitute.
Control Trial -place one other corn plant in a dark room

6. Energy Drink Experiment
Will drinking an energy drink enable you to run faster?
On 3 different days at the track, consume one can of energy drink.
Day 1: Monster, Day 2: Red Bull, Day 3: Rock Star)
Then run one lap as fast as you can.
Manipulated/Ind Variable:
-type of energy drinks
Responding/Dep Variable:
-how fast you run
Next do a control trail (see next slide)