Practicing the Scientific Process Part II:
“Designing a Scientific Experiment”
(Fill in the blanks)
Let's say you just started in a new school and:
1) You O______ed (noticed) that your classes are FAR apart and you’ve been late!
2) So, you want the fastest route from one class to another: that is your P______. Write it as a question:
"What's the fast______?”
Now, suppose there are TWO routes that you've identified from your observations:
Route 1 (R1) - the way you've BEEN going (that makes you late), and Route 2 (R2)
- "the ANSWER!". (At least you think it’s the answer.)
3) Will it work – will it make you faster? Your Answer is your
H______. Write your Hypothesis as an “if/then
statement”:
"IF I take Route # ___, THEN I ______(will/will not) get to class
faster than Route # ____."
Since the Route you take CAN BE CHANGED, it is called a "variable".
And, since your Route is the ONE "thing" you want to Test, you do so by changing it.
And then you observe the effect of the change YOU made.
4) So, we call the variable YOU change the "Tested Variable" - or the
"I______Variable" (IV).
5) By the way, ALL OTHER VARIABLES THAT COULD CHANGE, must be kept the
same, constant.
These variables are called "C______Variables".
What are you hoping for in this experiment? That the new route is faster, right?
TO BE SURE – and establish a FACT, you MUST carefully measure the TIME IT TAKES to get
to class using the new route (R2) (AND THE OLD ROUTE – R1).
6) Since the Travel Time CAN CHANGE also, it's a V______too.
Since the Travel Time DEPENDS on the Test/Independent Variable, we
call it the D______ent V______.
Think of the Independent Variable (IV) as "The Cause" and the Dependent Variable (DV) as
"The Effect" you hope to see (and be able to measure).
7) Now, what’s the NEXT step? You must run your E______!
Still along for the ride? Ok, next page...
QUESTIONS for PART II
1) WHY can there be only one Independent Variable (“test variable”)
that the scientist changes in an experiment? Explain.
(For example, in Part II, if you allowed other Variables to change,
Could you be certain that the new route was responsible
for a faster Travel Time - your measured Dependent Variable?
In other words, if you also changed the times of the day when you
tested the routes, would that be FAIR?)
2) Now, what are some OTHER variables - "Control Variables" - that
MUST be kept the same in the Classroom Travel Experiment, above?
(Think about what ELSE could affect how quickly you move to the next
class? What can make you get there earlier?)
3) In a true “Scientific Controlled Experiment”, the scientist must test the Independent Variable on a
“Test Group” - at least several individuals or specimens who are observed when their routine is changed.
On what Route (R1 or R2) did the Test Group Travel? ______
A “Control Group” of individuals who do NOT have any change made MUST also be observed, but under “normal” conditions.
On what Route (R1 or R2) did the Control Group Travel? ______
Why do you think BOTH groups are ALWAYS required. ______
______
______
Practicing the Scientific Process Part II.docx