Transcript Independent Variable

Following Directions
• Can you follow Directions?
Scientific Process
DO NOW
• Pick Up both Sheets on the Cart of Science
• Youtube Clips on Variables and Scientific
Method – on my website
• Think About – Does water increase growth in
plants?
Scientific Inquirysection 1.3
• Scientific inquiry refers to the diverse ways in which
scientists study the natural world and propose
explanations based on the evidence they gather.
The Scientific Method
• A planned organized approach to solving a
problem.
Step 1: Question
Curiosity about
an observation sparks a question.
• Scientific Inquiry begins with a problem, or a
question about an observation.
• Some questions can not be investigated by
scientific inquiry:
Does water increase growth in plants?
Does my dog eat more food than my
cat?
Which makes a better pet – a dog or a
cat?
Step 2: Research
Has anyone
ever tried to answer this question before?
• Once you have a question, you will try to gain some
insight into that question by conducting research.
• We learn from the work other scientists have done
before us.
Step 3: Hypothesis
you explain your observation?
How could
•A hypothesis is a testable statement. (If I do this…
then this will happen)
• A Hypothesis is an explanation to a question that
can be tested and supported with evidence.
• An educated guess.
• Once scientists have a hypothesis, they can test it
with an experiment.
Step 4: ExperimentDetermine if
your hypothesis is correct.
• Design an experiment.
• In every experiment there are variables and
controls.
• During the experiment scientists must collect data
and record the results.
Step 5: AnalyzeInterpret the
results of your experiment.
• Once the experiment is over, scientists analyze the
data in order to interpret it and reach a conclusion.
• Organize your data and look for trends.
• Compare the results with your hypothesis and
predictions.
Step 6: Conclude
Summarize what
you have learned from the experiment.
• Decide if your results supported your hypothesis.
• If not, the hypothesis is rejected.
• When a series of related hypotheses have been
tested and confirmed many times, in a variety of
experiments ,by a variety of scientists a theory is
born.
Step 6: Conclude
• A good scientist will verify their results further by
conducting the experiment many times in order to
make sure the results are the same each time.
• The final step is to communicate the results to
other scientists around the world.
Question
Does Gatorade
increase
growth in
plants?
Question
Research
Question
Research
Hypothesis
Question
Research
Hypothesis
Experiment
Question
Research
Hypothesis
Experiment
Analysis
Question
Research
Hypothesis
Experiment
Analysis
Conclusion
Constants, Controls, and Variables
Constants ( stay the same)
Control – Not
Tested
Independent Variable – Water (what is
tested)
Dependent Variable – Growth (cm) (the
outcome of the test)
Variable –
The Test
All Good Experiments Have
• Constants – Things that stay the same (time, temp, setting)
• Controls – Things that are not tested (normal)
• Variables – Things that change
– Independent – what the scientists change or test
– Dependent – changes that occur as a result of the test
(measure)
• Hypothesis – If the temperature (independent) is increased
then it will be more likely to rain (dependent)
Why do we use only One Variable?
• One Variable
• Two Variables
ONE VARIABLE
• If you change two or more variables at the
same time, you wouldn't know which one is
having an effect on the outcome. There might
also be no change - in that case, you don't
know which one is affecting the results either
way and how. By changing one at a time, you
can precisely measure what changes happen
and exactly how they are related.
Witch Skit
Brain POP
• http://www.brainpop.com/science/scientificin
quiry/scientificmethod/
DO NEXT
• Take a look at the dependent and
independent variables sheet
Science That was Proven
Wrong
http://www.youtube.com/watch?v=LqaDf2fuUH8
Great Scientific
Discoveries
(that were totally wrong)
Earth-centric Universe
Claudius Ptolemy
Galileo
The Planet Vulcan
Urbain Jean Joseph Le Verrier
Spontaneous Generation
Aristotle
Louis Pasteur
Expanding Earth
Nikola Tesla
Alfred Wegener
Martian Canals
Giovanni Schiaparelli.
Phrenology
Humorism
Hippocrates
Do Now
1) Take out your IDENTIFYING
VARIABLES Packet
2) Fill in the blanks below with your
neighbor
Every experiment needs to have _____________,
________________ and ____________.
All Good Experiments Have
• Constants – Things that stay the same (time, temp, setting)
• Controls – Things that are not tested (normal)
• Variables – Things that change
– Independent – what the scientists change or test
– Dependent – changes that occur as a result of the test
(measure)
• Hypothesis – If the temperature (independent) is increased
then it will be more likely to rain (dependent)
ONE VARIABLE
• If you change two or more variables at the
same time, you wouldn't know which one is
having an effect on the outcome. There might
also be no change - in that case, you don't
know which one is affecting the results either
way and how. By changing one at a time, you
can precisely measure what changes happen
and exactly how they are related.
DO NEXT
• Take out your Identifying Variables Packet
• Read over the instructions and the example
DO NOW (6 minutes)
• Please pick up Designing a Good Experiment and HEART LAB
on the cart in front of the supplies cabinet.
• PUT THIS IN YOUR AGENDA
– UNIT 1 ASSESSMENT NEXT FRIDAY 10/3
– Study guides will be available next week
• See if you and your neighbor can fill in the blanks on the
Designing a Good experiment sheet
Designing A Good
Experiment
Question
What is the effect of exercise on heart
rate?
Research
Designing A Good
Experiment
Once you have conducted your research
you need to formulate a
Hypothesis
Your hypothesis should be an IF - THEN
statement that attempts to answer your
question… (think about what you know
from your RESEARCH)
Designing a Good
Experiment
What is the effect of exercise on heart
rate?
Hypothesis
IF I exercise, THEN my heart rate will go
up.
Experiment
• In a well designed experiment you need to
have a control, variable, an constants.
Designing a Good Experiment
the control group
• A group of subjects in an experiment that are not
manipulated or given any special treatment.
• Everything stays the SAME for this group and it is
used for comparison.
Experimental Group
Won’t Exercise
Will Exercise
Designing a Good Experiment
Variables
•There are two different variables in
every experiment, the dependent
variable and the independent variable.
Variables
Independent
Dependent
• variables that are purposely
changed or manipulated in an
experiment
• the factor that you wish to
test
• usually expressed after the
word “if” in the hypothesis
• could be thought of as the
“cause” in a cause and effect
relationship
Example
The activity level (resting,
walking, running)
• variables that may change as a
result of the independent
variable
• the factor you measure to
gather results
• usually expressed after the
word “then” in the hypothesis
• could be thought of as the
“effect” in a cause and effect
relationship
Example
The person’s heart rate
Designing a Good
Experiment Constants
•
1.
Factors in an experiment (both in the
experimental and control groups) that are
kept the same and not allowed to change.
Examples
One minute was consistently the amount of time allotted to
perform the necessary activity
2.
The type of activity performed
3.
The stopwatch used during data collection
4.
The method used to measure the heart rate
HEART RATE LAB
• You will be working with your lab partner and another
group.
• So go find your lab partner
– Read over the lab
– Complete up to the Hypothesis
– Make certain you can find your pulse
– Find your resting Heart rate; (count beats for 10 seconds
and multiply by 6; 11 x 6 = 66 bpm)
Graphing Your Results
DEPENDENT
(Heart Rate)
• When graphing the results of any experiment, you
always put the independent variable on the x axis,
and the dependent variable on the y axis. ALWAYS.
INDEPENDENT
(Activity)
Graphing Your Results
1.
2.
3.
4.
5.
RULES TO GRAPH BY:
Always label the axis with the appropriate
variable.
Always include the units on each axis.
Always even space data points.
Always use as much space as is provided for you.
Always give the graph a title.
Identify the Variables:
• I want to measure the influence of different quantities
of fertilizer on plant growth.
• Dependent Variables:
• Independent Variable:
• Constants:
• Control Group:
Identify the Variables:
• I want to measure the influence of different
quantities of fertilizer on plant growth.
• Dependent Variables: growth in height/mass of the
plant.
• Independent Variable: amount of fertilizer used.
• Constants: type of plant, type of soil, type of
fertilizer, sunlight, size of the pots.
• Control Group: a group of plants that gets no
fertilizer.
Variables
• If you are confused try using this sentence…
• How tall the plants will grow DEPENDS on how
much fertilizer I give them.
• The amount of fertilizer is independent (you are
manipulating it)
• The height is dependent (effected by what you do)
Identify the Variables:
• I want to study how different doses of a drug affect the
severity of symptoms
• Dependent:
• Independent:
• Constants:
• Control Group:
Identify the Variables:
• I want to study how different doses of a drug affect
the severity of symptoms
• Dependent: The severity and frequency of the
symptoms.
• Independent: The amount of drug per dose
• Constants: The type of drug, the type of disease,
the types of symptoms.
• Control Group: A group of sick people who get no
drug, or a placebo.
• How severe will the patients symptoms be? It
DEPENDS on how much medicine I give them.
Graphing Your Results
DEPENDENT
• When graphing the results of any experiment, you
always put the independent variable on the x axis,
and the dependent variable on the y axis. ALWAYS.
INDEPENDENT
Graphing Your Results
1.
2.
3.
4.
5.
RULES TO GRAPH BY:
Always label the axis with the appropriate
variable.
Always include the units on each axis.
Always even space data points.
Always use as much space as is provided for you.
Always give the graph a title.
Identify the Variables:
• I want to measure the influence of different quantities
of fertilizer on plant growth.
RESULTS
• Dependent Variables:
Plant 1
Plant 2
Plant 3
Plant 4
Amount
of
fertilizer
given
(cups)
0 cups
½ cup
1cup
1 ½ cups
Growth
of Plant
(inches)
2 in.
4in.
6in.
8in.
• Independent Variable:
• Constants:
• Control Group:
DO NOW
Work with your lab partner to obtain the following
materials quickly and in an organized manner.
1. 2 lab sheets from the do now basket (one for
each of you)
2. 1 meter stick (in the box by the sink)
3. 1 small piece of red string (next to the sink)
4. 1 piece of wax paper labeled as shown.
5. Gum (From Mrs. Burke)
6. Get back to your seat and wait for verbal
directions.
A B
DO NOW
Quickly draw this table in your notebook:
Independe Dependent
nt Variable Variable
Control
Constants
Take a bean lab from the do now basket.
BEAN LAB
Question: What variables can affect the
growth of a bean?
TYPE OF SOIL
SUNLIGHT
TYPE OF BEAN
WATER
BEAN LAB: TODAY’S
GOALS
• You will choose a variable that you wish to
investigate and fill out the chart you copied into
your notebook.
Hints:
• Next you will write a hypothesis. 1) Number the steps
• Next you will complete the procedure.
2) Be Detailed
3) Someone must be
able
to follow them.
4) Think of a recipe
BEAN LAB: TODAY’S
GOALS
• Once Mrs. Burke has approved your procedure you
may use the materials set up in the back of the
room to set up your experiment.
•The procedure should be followed
EXACTALY
•Materials need to be carefully
measured.
•All cups should be labeled and set up in
an appropriate location in the classroom
DO NOW
•Take out your bean lab.
•Put all of your books and other
belongings off to the side of the room
(near the net books, on the heater, or under the
red cat)
• DO NOT TOUCH ANYTHING IN THE
LAB STATIONS UNTIL YOU ARE
INSTRUCTUED TO DO SO!
• Observe your beans and record your observations.
• Get a lab sheet from the do now basket.
Measuring Liquid Volume
How well can you follow directions?
Bean Conclusion:
•Paragraph 1:
•Explain the variable you were testing.
Summarize your experiment. (What did
you do, constants, control, set up.)
•Paragraph 2:
•Summarize your results. Look at all of your
observations and explain what happened
over the course of the experiment.
•Discuss possible sources ofDUE
error.
TUESDAY 10/15
one separate sheet of
paper
How to make a wet mount
slide…
• You will need a clean slide, a clean cover slip,
a pipette and a beaker of water.
• Obtain a small, THIN, sample of onion skin.
Using tweezers, place the skin on the slide.
(the more purple the better)
• Add ONE drop of water on top of the skin.
• Drag the cover slip along the slide at a 45
degree angle until you reach the edge of the
specimen, then carefully drop it into place.
• Absorb any excess water.
How to make a wet mount
slide…