STEM Fair

# Variables

Created 3 years ago

Duration 0:04:40
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Slide Content
Tags: STEM Fair

• Variables
2. ### Slide 2 - What is a variable?

• A variable is any component in a science experiment that can exist in different amounts or types.
• Experiments have three types of variables:
• A manipulated variable (also known as an independent variable).
• A responding variable (also known as a dependent variable).
• Controlled variables
3. ### Slide 3 - Manipulated variable

• Also known as the independent variable.
• The factor that is intentionally changed in an experimental procedure in order to find the effect on something else.
• Bottom line- you change this component on purpose in your experiment.
• NOTE– You should only have ONE manipulated variable in your experiment.
4. ### Slide 4 - Example…

• You are interested in conducting a month long experiment in order to find out which soil a sunflower grows best in.
• You choose three soils to plant the seed in (clay soil, silt soil, sandy soil).
• What is the manipulated (independent) variable in your experiment?
• THINK- What are you changing in this experiment?
• Photo credit: http://www. www.clipartpal.com
5. ### Slide 5 - Answer…

• The manipulated variable is the type of soil that you are planting your seed in.
• Why? You chose three different types of soil to see which one the sunflower seed will grow the best in.
• Sandy soil
• Clay soil
• Silt soil
• Photo credit: http://www.wisegeek.com/what-are-the-different-types-of-soil.htm#
6. ### Slide 6 - Responding variable

• Also known as the dependent variable.
• The factor that is observed and measured to see if it is affected by the change made in the independent variable.
• Bottom line- The responding variable is dependent on the manipulated variable.
• Ask yourself… what am I testing in this experiment?
7. ### Slide 7 - Example…

• You are interested in conducting a month long experiment in order to find out which soil a sunflower grows best in.
• You choose three soils to plant the seed in (clay soil, silt soil, sandy soil).
• What is dependent on the manipulated variable (the type of soil) in this experiment?
• What are you looking for in this experiment?
• What are you measuring?
8. ### Slide 8 - Answer…

• In this experiment, you are looking to see in which type of soil the sunflower will grow best in.
• The responding (dependent) variable is the growth of the sunflower seed.
• Why? The growth of the sunflower seed is dependent (relies on), or depends on the types of soil that you chose (also the manipulated variable).
9. ### Slide 9 - Controlled variables

• Controlled variables are the factors in the investigation that must be kept exactly the same so that they have no effect on the dependent variable.
• Bottom line- Remember that you can only have ONE manipulated variable.
• EVERYTHING ELSE MUST REMAIN THE SAME.
• What would need to remain the same in the plant experiment?
• Photo credit: http://www. thegraphicsfairy.com
10. ### Slide 10 - Answer…

• Your manipulated (independent) variable is the type of soil.
• Therefore, you must keep everything else the same in your experiment.
• The controlled variables in this experiment include:
• The type of sunflower seed.
• The brand of each soil.
• The amount of soil you use to plant each seed.
• The cup.
• The placement of the cup in a room to measure growth.
• The temperature of the room.
• The amount of sunlight the cups receive.
• The amount of water you use to water the plants.
• The ruler you use to measure the plants.