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SPI 0807.Inq.1 (Variables and Controls)

Aug 20, 2013

Imagine that an engineer has designed a rocket backpack that will enable a personto fly like superman.

However, he needs to test it to make sureit is safe enough for people to use, and he wants you to help him with these experiments.

1) Write about some careful ways to test this rocket backpack.2) Decide how many tests you would conduct, and explain why.

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Slide 1

Notes

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SPI 0807.Inq.1 (Variables and Controls)

Experimental Setup This is a key part of the scientific method

Scientific Method(In Flow Chart Format)

You do experiments when you test your hypothesis

Experiments In an experiment you measure a quantity and/or quality of

something. In an experiment you should conduct multiple trials In other words you should duplicate your efforts several times

Example: Scientists could be testing a new cancer medicine to determine

how effective it is Scientists could be measuring the fuel consumption of a new

type of car engine that could replace current engines

Notes SPI 0807.Inq.1 (Variables and Controls)

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Main Experiment Your main experiment will include…

The purpose of this experiment is to measure ONE key thing in multiple trials

Control ExperimentAn experiment to verify the results of your main experiment using the same conditions except for one factor or variable

Notes SPI 0807.Inq.1 (Variables and Controls)

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Two Types of Experiments(1) Main Experiment(2) Control Experiment

independent variables, dependent variables, and constants

Sometimes called experimental group

Sometimes called control group

Independent variable:The one thing YOU change each time you duplicate an experiment

Here is a simple memory trick to help you remember this

Independent variable begins with the letter “I,” so

remember the letter “I.” Imagine yourself doing the experiment., and say this…

“What is the ONE thing I would change when repeating the experiment?” That one thing will be the…

Note: Anything else that changes on its own will be a dependent variable

Notes SPI 0807.Inq.1 (Variables and Controls)

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independent variable.

Reminder:

Example 01:

So…what is the independent variable in this example?In other words, what is the one thing YOU would change each time you repeat your experiment?

change each time you repeat the experiment

Review SPI 0807.Inq.1 (Variables and Controls)

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The independent variable is the type of soft drink

YOU The independent variable is the one thing

You decide to do an experiment to determine the reason certain soft drinks are more popular than other soft drinks. You suspect that the popularity of the drinks is connected with the amount of sugar found in them. You decide to use Coke, Pepsi, and Dr. Pepper in this experiment. You first determine how much sugar each drink contains. Then you get 6 students to do a blind taste test with all 3 drinks.

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Reminder: :

Example 01:

What was the independent variable?In other words, what was the one thing YOU changed each time?

Dependent VariablesNote: Anything else that changes on its own will be a dependent variableOther factors that change because of the independent variable

Notes SPI 0807.Inq.1 (Variables and Controls)

6The independent variable was the type of soft drink

(Pepsi, Coke, or Dr. Pepper)

YOU The independent variable is the one thing change each time you repeat the experiment

You decide to do an experiment to determine if theamount of sugar in three different soft drinks is connected with the popularity of the soft drinks. (Pepsi, Coke, & Dr. Pepper) First you measure the amount of sugar in each soft drink. Then you ask a person to drink 50mL of Pepsi and to rate the drink on a scale of one to ten. Then you duplicate this procedure using Coke in the same manner. You duplicate it again using Dr. Pepper.

Example 02:

So…what is the independent variable in this example?In other words, what is the one thing YOU would change each time you repeat your experiment?

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.

SPI 0807.Inq.1 (Variables and Controls)

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The independent variable is the distance from the sunlamps which is connected with the amount of sunlight.

Slide 7Review

Example 03:

So…what is the independent variable in this example?In other words, what is the one thing YOU would change each time you repeat your experiment?

A student conducts an experiment with ten 8th grade students. He uses 3 similar types of sour candy (Sour Skittles, Sour Patch Kids, and Warheads) in a series of 4 trials. He gives 1 piece of candy to each student and records their facial expressions as they eat it.

SPI 0807.Inq.1 (Variables and Controls)

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The independent variable is the type of sour candy

Slide 8Review

Example 04: A student conducts an experiment to determinewhich type of glue works best for attaching two pieces of regularwriting paper together.

She uses 3 types of Elmer’s glue in a series of experiments. (1) Liquid-washable, (2) Glue Stick-washable, (3) Glue Stick-nonwashable) She places the same amount of glue (2g) on each sheet of paper.

SPI 0807.Inq.1 (Variables and Controls)

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The independent variable is the type of glue

So…what is the independent variable in this example?In other words, what is the one thing YOU would change each time you repeat your experiment?

Slide 9Review

Example 05: A student conducts an experiment to determine whichink color in ballpoint pens will last the longest before running out.

She uses 3 ink colors in 3 ballpoint pens in a series of experiments. (1) Black ink pen, (2) Blue ink pen, (3) Red ink pen) She copies text from her science book. She copies the same text overand over. She writes at the same speed. The room temperature remains the same. She writes on the same kind of paper.

SPI 0807.Inq.1 (Variables and Controls)

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The independent variable is the color of ink

So…what is the independent variable in this example?In other words, what is the one thing YOU would change each time you repeat your experiment?

Slide 10Review

BellWork

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SPI 0807.Inq.1 (Variables and Controls)

Aug 16, 2013

Congratulations! You have been hired to conduct experiments todetermine which gaming system can process game images the fastest.In one experiment you will play X-Box games for one hour.In the next experiment you will play Wii games for one hourIn the third trial you will play Playstation games for one hours.

1) In this experimental setup, what is the independent variable?In other words, what is the one and only one thing changed each time the experiment is duplicated?

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Slide 1

A student conducted an experiment to determine if energy drinks can help you run faster. He had ten 8th grade students participate. (5 girls and 5 boys). He first recorded the amount of time it tookeach student to run a distance of 30m. Then he conducted 3 trials changing the energy drink being used each time. For each trial thestudents were given exactly 355mL (12 oz) to drink. Each trialoccurred in the gym, and the temperature was 22.2o C (72o F).1st trial: Day 01-Run 30m after drinking Monster energy drink2nd trial: Day 02-Run 30m after drinking Red Bull energy drink3rd trial: Day 03-Run 30m after drinking Rock Star energy drinkNote: The independent variable was the type of energy drink

(1) What are some dependent variables from this experiment?(2) Next list (at least) three constants from this experiment

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SPI 0807.Inq.1 (Variables and Controls)

Aug 20, 2013

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Dependent variables: (things the experimenter did not change-changed on their own )how fast each student ran, how much sweat they produced, how heavy was their breathing, etc.

Constants: (things that did not change)

same group of 10 students each trial, same distance each trial (30m), same amount of drink each trial (355mL), same location (gym), same temperature (22.2o C).

A student conducts an experiment to determine the relativestrength of boys versus girls. She has six 8th grade studentsparticipate (3 girls and 3 boys). She conducts three trials. In eachtrial she has each student, one at a time, lift a weight above theirhead (s) as many times as they can. 1st trial: The weight is 5 pounds2nd trial: The weight is 10 pounds3rd trial: The weight is 15 pounds

Question:(1) What is the independent variable in this experiment?(2) What other factor(s) changed during this experiment?

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SPI 0807.Inq.1 (Variables and Controls)

Aug 19, 2013

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Independent variable was the amount of weight

Other changed factors include the number of repetitions, how much each student strained, how much sweat they produced, how heavy was their breathing, etc.

These other changed factors are called dependent variables

The independent variable is…

Notes SPI 0807.Inq.1 (Variables and Controls)

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The dependent variable is the student’s rating

You decide to do an experiment to determine the reason certain soft drinks are more popular than other soft drinks. You suspect that the popularity of the drinks is connected with the amount of sugar found in them. You decide to use Coke, Pepsi, and Dr. Pepper in this experiment. You first determine how much sugar each drink contains. Then you get 6 students to do a blind taste test with all 3 drinks. They rate each drink on a scale of 1 to 10.

Example 01

the type of soft drink

So what is the dependent variable?

HINT: What is a factor that changed without you doing it?

Example 02:

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.

Notes SPI 0807.Inq.1 (Variables and Controls)

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The dependent variable is the plant growth

The independent variable is…the distance from the sunlamp

So what is the dependent variable?

HINT: What is a factor that changed without you doing it?

Example 03: A student conducts an experiment with ten 8th grade students (5 boys and 5 girls). He uses 3 similar types of sour candy (Sour Skittles, Sour Patch Kids, and Warheads) in a series of 4 trials. He gives 1 piece of candy to each student and records their facial expressions as they eat it.

Notes SPI 0807.Inq.1 (Variables and Controls)

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The dependent variable is the student’s facial reactions

The independent variable is…the type of sour candy

So what is the dependent variable?

HINT: What is a factor that changed without you doing it?