Transcript What is the Scientific Method?

What is the
Scientific Method?
Organized
An___________
approach to
perform an
experiment
____________
Problem
1. Define________
1. A problem can't be solved if it isn't
understood
____________
2. Write the problem in the form of a
question
____________
3. Ex: How does smoking affect a
person’s breathing rate during
exercise?
2. Form a __________
Hypothesis
1. A __________
Prediction based on __________
research
and ___________
Observations
statement
2. Written in the form of a _________.
3. Ex: I think that a smoker will have
a higher breathing rate during
exercise than a non-smoker.
Experiment
3. Do the _________
1. Experiments test the _____________
hypothesis
2. The experiment will prove whether or
not your hypothesis was
________________________
Correct or incorrect
3. Every experiment needs at least
____________________
Three groups (variables)
a. Experimental Group – consists
of _________variables
two
i. Dependent Variable - What you are in
______________the
experiment
measuring
– Ex: breathing rate, heart rate, blood
pressure, height of plant, etc.
ii. Independent Variable - conditions
_________________
varied or changed by experimenter
– smokers vs. nonsmokers
Control Group:
b. Control Group –all variables
________
are kept _____________
to insure
constant
that they do not affect the
outcome
___________
of experiment
– EX: age, weight, gender, length of
exercise, # years smoking
4. Results/Observations
1. __________
____
Record and ________
analyze
data
2. Includes
_______,________,________
charts graphs statistics etc.
5. Conclusions:
1. In it's simplest form, the conclusion
will be "yes" the hypothesis was
__________
or "no" the hypothesis was
correct
_____________.
not correct
2. All experiments should be
_________________
Peer-reviewed
3. All experiments should be ___________
repeated
over and over again to assure accuracy
Why does
Bread turn
Moldy?
Bread Mold
• As you know, we keep food in
refrigerators so it will last longer.
But still, sometimes you open a bag
of bread or a jar of spaghetti sauce
and what do you find? Mold!!
• Ever wonder exactly what mold is?
And how did it get there? And why
sometimes it’s green and other
times black or white? Did you know
this stuff is alive and growing?
Bread Mold
• In this experiment, you’ll find out
all about those colorful, fuzzy fungi
by growing your own crop.
• Note: This is a long-term activity. It
will take several days for the mold
to grow. The first day should take
about 30 minutes to one hour. For
safety reasons, don’t eat or drink
while doing this experiment. And
don’t taste or eat any of the
materials used in the activity.
2. Wash your hands. Place a slice of
white bread in the bag labeled "Dry
White Bread" and seal the bag.
– Using one eye dropper, sprinkle 20 drops
of tap water on another slice of white
bread. (Don’t overdo it; the bread should
be moist, not wet. If your bread is
dripping, you’ve definitely done way too
much. Throw away that slice and try
again.)
Materials:
• 3 eye droppers
• small cup filled with 4 teaspoons or 20
mL of sugar water
• small cup filled with 4 teaspoons or 20
mL lemon juice
• small cup filled with 4 teaspoons or 20
mL tap water
• 4 slices of plain white bread
• 4 slices of assorted bread, such as
wheat, rye, sourdough, etc.
• 8 resealable plastic sandwich bags
• marker
• masking tape
Procedure:
1. Using masking tape and marker,
make labels for four sandwich
bags. Label the first bag "Dry
White Bread." Label the second
"Water on White Bread," the third
"Lemon Juice on White Bread,"
and the fourth "Sugar Water on
White Bread."
• Place the moist bread in the bag
marked "Water on White Bread" and
seal the bag.
• Using a different eye dropper, sprinkle
20 drops of lemon juice on another
slice of white bread and put it in the
bag marked "Lemon Juice on White
Bread" and seal the bag.
• Using your third eye dropper, sprinkle
20 drops of sugar water on the last
slice of white bread and place it in the
bag labeled "Sugar Water on White
Bread" and seal. Try to keep your
fingers off moist spots when handling
each slice of bread.
3. Repeat steps 1 and 2, but
this time use a different
kind of bread in the
remaining four bags.
• Your labels should note
what kind of bread you’re
using.
• Wash your hands when
you’re done.
• 4. Make sure all of your bags
are tightly sealed.
• Place all eight bags in a dark,
warm place (about 86 degrees
Fahrenheit, 30 degrees
Celsius).
• Check the bags each day for
two weeks and record the
results in a notebook.
• You may wish to draw or take
pictures of the bread slices.
Don’t open the bags!
5. Make a graph recording the
total growth of mold on each of
the four white bread slices at
the end of two weeks
• Make a similar graph for the
other four bread slices.
Compare the results.
• At the end of the two weeks,
throw out all the bags
unopened
Sample Graph:
Questions:
• What is your hypothesis?
• What were the variables used in your
experiment?
• What was the control?
• Could factors other than water and
sunlight have influenced your results?
Explain.
Additional Questions:
1. From this activity can you tell
what helps mold to grow best?
2. Does it matter what kind of bread
you use?
3. What causes the different colors
you see?
4. What would happen if you left the
bags in a well-lit place instead of
a dark place?
5. What would happen if you
changed the temperature?
1. From this activity can you tell
what helps mold to grow best?
• Unless you used bread that had been sitting out
for many days, you probably didn’t get much or
any mold growth on the dry bread.
• Clearly, water is important for the growth of mold.
The mold grew best on bread sprinkled with sugar
water because the sugar serves as food for the
fungi. The more food that’s available, the more
fungi cells can grow.
• The mold also grew pretty well on the bread with
plain tap water because the fungi could use the
sugar and starch in the bread as food.
• The mold didn’t grow as well on the bread
sprinkled with lemon juice because lemon juice is
2. Does it matter what
kind of bread you use?
• Molds grow better on some kinds of
breads than others depending on the
ingredients used and how the bread
was made.
• Some breads are dry and some are
moist. The amount of the sugar in
different breads varies; some have
sugar, honey or molasses added. Some
breads are even acidic, such as
sourdough. Some may have fruit or
nuts or other ingredients added.
• Many commercial breads are made
with preservatives that hinder the
growth of molds and bacteria to
prevent or delay spoilage.
• Bread baked fresh in a bakery that
doesn’t use preservatives will more
likely become moldy faster. All of
these factors can influence how
much mold will grow on a particular
kind of bread.
3. What causes the
different colors you see?
• Many of the colors you see on the moldy
bread are due to the spores the fungi have
produced.
• Molds reproduce by making spores at the end
of stalks that rises above the surface of the
bread, giving molds a fuzzy appearance.
• Spores are like seeds—they spread molds to
new places so that they can continue to grow.
Spores are usually colorful.
Fungi:
• Some fungi, such as Rhizopus
nigricans (rye-zoh-puss neye-grihcans) and Aspergillus niger (As-perjill-us neye-jer), make black spores.
• Neurospora crassa (new-rah-sporeah crah-sah) produces spores that
appear pink.
• And the Penicillium (pen-ih-sill-eeum) molds, the molds that make
penicillin, are blue-green.
Bacteria:
• Some of the colors on your bread
may be the result of growing
colonies of bacteria, which also
sometimes grow on old food.
• For example, a bacterium called
Serratia marcescens (ser-ay-shuh
mar-seh-sens) forms reddish
colonies.
• You can tell bacteria colonies apart
from molds because bacteria
colonies appear smooth while molds
4. What would happen if you left
the bags in a well-lit place
instead of a dark place?
• Molds grow best in the dark, so
not as much mold would be
present on bread slices kept in a
well-lit place.
5. What would happen if you
changed the temperature?
• Most fungi grow best around room
temperature.
• But they can grow at a range of
temperatures from cold (like in a
refrigerator) to quite warm (body
temperature).
• At temperatures colder or warmer than
their favorite temperature, they usually
do not grow as rapidly.
• If the temperature is too cold or too hot,
they will not grow at all, and may even