What do you already know

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What do you already know?
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How to Design a Good Experiment
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Why do science?
The purpose of science is to figure out how
things work.
?
What about just guessing? assuming we kno
w?

?
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Lesson 1

• What are VARIABLES and their VALUES?

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Vari
able
What does able mean?
What does vary mean?
change
can
If we combine these words to make variable, what
do we get?
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A variable is something that can be changed in an
experiment
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The choices you have for a variable are its VALUES
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Two examples of variables and their values
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What are some variables and values that could
affect car sales?

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What are some VARIABLES and VALUES that could
affect car sales?

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What are some VARIABLES and VALUES that could
affect car sales?

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In all experiments

• Variables are things that can be varied or
  changed.
  
• Values are the choices you have for each
  variable.

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How to design good experiments
Lesson 2
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What is a good experiment?
A good experiment is one that allows you to
figure out whether a variable affects the result.
Controlled experiments
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What can we say after doing a good experiment?
We can say whether the variable has an effect.
For example, we can say The type of pet you hav
e does affect how much exercise you get!
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What else can we say after doing a good
experiment?
We can also see how the values compare to one
another.
For example we could say People who own iguana
s get less exercise than people with dogs, cats,
fish, and hamsters.
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Question 2
Packet Page 2, Question 2
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What kinds of study habits influence grades?

• Lets design experiments that could help us
  figure that out!
  
• Well have two groups of students in our
  experiment.
  

Group 1
Group 2
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What are some studying variables that might have
an effect on grades?
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What are some studying variables that might have
an effect on grades?
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An experiment can have many variables, but

• How many variables should you TEST at one time?

Packet Page 2, Question 4
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We should only test ONE variable at a time!

• The experiment will HAVE more than one variable,
  but we only test ONE.
  
• We would do a second experiment to test one of
  the other variables.
  

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We should only test one variable during this
experiment
Experimental question Does LOCATION affect gra
des?

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We should only test one variable during this
experiment
Experimental question Does LOCATION affect gra
des?

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Remember our experimental question Does
LOCATION affect grades?

Remember, putting different here means that we
want the value for Group 1 to be DIFFERENT than
the value for Group 2.
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Remember our experimental question Does
LOCATION affect grades?
Remember, putting same here means that we want
the values for Group 1 and Group 2 to be the SAME.
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Review the procedure

• Underline what variable youre testing.
• Make the group values DIFFERENT for the variable
  youre testing.
  
• Make the group values the SAME for the variables
  youre not testing.

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Remember This experiment was only to test
whether LOCATION affects grades.
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A) What would be another experiment?
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B) Lets look at another experiment
Could we have tested LOCATION by doing this ex
periment?
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Lets consider SHIRT COLOR as a variable in our
experiment! (Were still testing LOCATION.)
Even if we think a variable does not matter, we
make its values the SAME for both groups.
(Why? Because maybe were wrong!)
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Question 8, page 4

• How would you explain to a friend the way to make
  a good experiment?

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Lets Practice!
Does X affect grades?
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Does X affect grades?
Without saying anything, decide whether this is a
good experiment and explain why or why not on
your worksheet.

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Is this a good experiment? Lets think about our
procedure
1. Are the group values DIFFERENT for the
variable were testing?
2. Are the group values the SAME for all the
other variables?
Because this is a good experiment, we WILL be
able to find out whether X, the variable were
testing, affects grades.

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How did you do?
Exchange papers with someone. Everyones Same/Dif
ferent column should have looked like this
v or X
v or X
v or X
v or X

• Put a v next to the rows the person filled out
  correctly
  
• Put a X next to the rows that were incorrect
• Give the paper back

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Did you set up each variable correctly?

• GREAT JOB!!!!
• This is a good experiment!

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Possible Results?
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3 possible results

• Group 1 could get better grades
• Group 2 could get better grades
• Group 1 and 2 could get the same gradesthere is
  no difference in grades.
  

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3 possible results
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Possible result 1 Group 1 had better grades
So what would this tell us?
_X_ __does/does not__ affect grades.
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Possible result 2 Group 2 had better grades
So what does this result tell us?
_X_ __does/does not__ affect grades.
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Possible result 3 Neither group had better
grades
So what does this result tell us?
_X_ __does/does not__ affect grades.
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Lets apply what weve learned!
Packet Page 5-6, Question 11
Do people who have pet birds get different
amounts of exercise than people with pet snakes?
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Say it yourself!
Packet Page 6, Question 12

• Put what weve learned about HOW to design good
  experiments into your own words.

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End Lesson 2
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Remember the last lesson?

• Do Packet Page 7, Question 13

Review Packet Page 5, Question 11
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Lesson 3

• Why do we design experiments the way we do?

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Ramps!
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Parts of the ramp you can change
Surface Height Track length Type of Ball
High Ramp
Long
Short
Low Ramp
Smooth
Rough
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How to assemble a ramp
(Exit slide show to set up)
Low Ramp
High Ramp
How to Set Up
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Question 14 What are the ramp VARIABLES and
VALUES?
Surface Height Track length Type of Ball
High Ramp
Long
Short
Low Ramp
Smooth
Rough
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Question 14 List the variables and their values
for ramps in the first two columns
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Experimental question
Does the HEIGHT of the ramps affect how far balls
roll?

• What variable are we testing?
• HEIGHT
• What is our result?
• HOW FAR THE BALL ROLLS

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Does the HEIGHT of the ramps affect how far balls
roll?
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Does the HEIGHT of the ramps affect how far balls
roll?Question 15) Design an experiment to find
out!

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Design your own ramp experiments
Packet Page 8, Question 16 (a, b, c)
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Does the HEIGHT affect how far balls roll?
Whats good about this experimental set up?
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Does the HEIGHT affect how far balls roll?
Whats wrong with this experimental set up?
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Does the HEIGHT affect how far balls roll?
Whats good about this experimental set up?
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Does the HEIGHT affect how far balls roll?
Whats wrong with this experimental set up?
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Student experiment Does the HEIGHT affect how
far balls roll?
Whats GOOD about how this experiment is set up?
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Student experiment Does the HEIGHT affect how
far balls roll?
Whats wrong with how this experiment is set up?
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CORRECTED student experiment Does the HEIGHT
affect how far balls roll?
Fill in Question 18, Part A
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The result!
Result 4.3 inches
Low Ramp
14 13 12 11 10 9 8 7 6 5 4 3 2 1
High Ramp
Result 6 inches
14 13 12 11 10 9 8 7 6 5 4 3 2 1
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Was it a good test? Why? (Question 18, Part B)
Result 4.3 inches
Low Ramp
14 13 12 11 10 9 8 7 6 5 4 3 2 1
High Ramp
Result 6 inches
14 13 12 11 10 9 8 7 6 5 4 3 2 1
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What if this happened instead?
Result 4.3 inches
Low Ramp
14 13 12 11 10 9 8 7 6 5 4 3 2 1
High Ramp
Result 6 inches
14 13 12 11 10 9 8 7 6 5 4 3 2 1
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Or this?
Result 4.3 inches
Low Ramp
14 13 12 11 10 9 8 7 6 5 4 3 2 1
High Ramp
Result 6 inches
14 13 12 11 10 9 8 7 6 5 4 3 2 1
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Now, choose a different variable to test
Packet Page 10, Question 19
Design an experiment to test a different
variable. We will check it next!
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Exchange papers to check Question 19!

• Did the ramps have different values for the
  variable you were testing? (mark with a ?or X)
  
• Did the ramps have the same values for each of
  the other 3 variables? (mark with a ? or X)
  
• If you did.
• Congratulations!!! You designed a good
  experiment for the variable YOU were interested
  in testing!

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Summary

• A good experiment is one that allows you to
  figure out whether a variable affects the
  result.
  
• To design a good experiment, you need to make the
  values for the variable you are testing different
  and make the values for all the other variables
  the same.

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Summary

• You can only trust the results of an experiment
  when the values for the variable you are testing
  are different and the values for the other
  variables are all the same.

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Challenge 1

• Packet Page 11, Challenge Question 1

Suppose you were visiting a different planet and
the aliens wanted to know how Earthlings design
good experiments. They dont speak English, so
you have to show them using symbols.
1) Choose the variable you want to test by und
erlining it. 2) Then, complete the table by us
ing the rules of designing a good experiment.

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Challenge 2
Packet Page 12, Challenge Question 2

• The diagrams show different trials Abdul carried
  out with carts having different-sized wheels.
  
• He started them from different heights and the
  blocks he put in them were ofequal mass.
  
• Abdul wants to test this idea The heavier the
  cart is, the greater its speed at the bottom of a
  ramp.
  

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Challenge 3
Packet Page 13, Challenge Question 3

• Design Your Own Experiment
• What is your experimental question?
• What variable are you testing?
• What other variables are part of
  yourexperiment?
  
• What will you look at as your result?
• How many groups will you compare?
• Explain your design!

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What have we learned?
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What have we learned (and still remember)?
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END OF INSTRUCTION