Transcript 10/22: Independent vs. Dependent Variable and Lab

1. What would the eagles do if the weasels
disappeared?
2. What would happen to the snakes if the
rabbits decreased (Shared Predator) Why?
eagles
weasels snakes
rabbits
field mice
grasses
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BIRD BEAK LAB
A lesson in adaptations
Question of the Day
• What adaptation
did the bird that
ate the most
have? How did
that adaptation
help the bird to
survive?
Background
• In any habitat, food is limited and the
types of foods available may vary.
• Animals that have variations that enable
them to take advantage of available
foods will be more likely to survive.
• We call beneficial inherited variations
adaptations.
• Adaptations are inherited
characteristics that increase an
organism’s chance of survival.
PROCEDURES
1. Mr. Vo will ask one student to help
demonstrate with each “beak”.
2. We are now all very hungry birds. The tool
we have selected is our “beak”. Wecan only
use our beak to pick up food. NO HANDS!
3. The cup is our stomach. It must remain
upright at all times. We must hold our beak
in one hand and our stomach in our other
hand, close to our body. Only food that is
placed in the cup by the beak has been
“eaten”.
4. Food items will be placed in our “habitat”.
5. When I say, “Go” you will have 30 seconds to
feed (or until the food runs out). Collect as
much food in your stomach as possible until I
say “Stop”.
6. Then empty our stomach and count the
contents. Record data in the Individual Data
Table. Put all food items back into the Ziploc
bag.
7. Repeat the activity with another food item
until all items have been recorded.
Hypothesis
• Make a prediction as to which type
of beak will be able to collect the
most of each type of food.
• Your hypothesis should state which
will be the best type of beak for each
type of food and explain why you
think that.
Note
• Anyone who is not responsible
enough to maintain safe behavior at
all times will no longer participate in
the activity and will become an
observer.
Class Data
Beak Spoon 3 Binder Clip 8 Tweezers 5 1 Scissors Paper Clips Cereal Rubber Bands Thumb tacks 32 7 1 20 2 5 17 10 7 4 7 3 Use the Class Data to answer the ANALYSIS Section
We’re going to use this
lab to talk variables 
Let’s talk relationships…
• Who is the
dependent one?
• What does it
mean to be
dependant?
• What does it
mean to be
independent?
Variables
• Today we are going to learn
the difference between an
independent and dependant
variable.
Variables
• A (1) variable is a factor
that can (2) change in an
experiment.
Independent Variable
• An independent variable is a change
that occurs in an experiment that is
(4) a change directly caused by the
experimenter.
• It is what the scientist is choosing to
change as they conduct an
experiment.
Dependant Variable
• A dependent variable is (5) the
change that occurs due to the
independent variable.
• This change is not directly made by
the scientist, but as a result of the
independent variable.
• The dependent variable is the thing
that you are measuring.
Variables
• To make it easy, think of the
independent variable as the
cause, and the dependent
variable as the effect.
Example
• Question: Does the type of
bug spray affects the number
of bugs that die?
Example
Independent Variable
• In that experiment, the scientist was
CHOOSING to change (6) the type of
bug spray that was used, making it
the independent variable.
Example
Dependent Variable
• You could measure and test (7) the
number of bugs that died when you
changed the type of bug spray.
• That would be the dependent variable
because it is occurring due to the type of
bug spray you are using, and it is what
you are measuring in the experiment.
Variables
• When testing for independent or
dependant variable, ask:
• Is this variable depending on the
other one?
–If the answer is NO- Independent
–If the answer is YES- Dependent
Example
• Question: What type of ice cream
treat will stay cold for the longest
amount of time?
Example
Independent Variable
• The thing that will be changed is the type
of ice cream treat.
• The scientist cannot directly change time.
• The independent variable is the type of
ice cream treat because it is the change
that is being made.
Example
Dependent Variable
• Next, I need to look for what the
independent variable is affecting.
• The type of ice cream determines how
long it will stay cold.
• The dependent variable is the amount of
time that is stays cold because it is
affected by the independent variable.
3.) Create an appropriate bar graph for the class
data for this experiment.
Title: Spoon’s Effectiveness in Picking Various Foods