Summary:
This
center allows students to use oranges to informally explore decomposition,
dehydration, fermentation, the water cycle, bacteria, yeast, food webs, the
needs of living things, and physical vs. chemical change over a period of
three or more months.
Note: Children
who are sensitive to fungi such as mold or yeast should not open the oranges
in ZipLoc bags once the fruit begins to decompose.
Day
1: Introduction and Set Up (15 min.)
Ready...
- Gather Center
Materials
- two wide-mouthed
jars with lids (salsa or pickle stacker jars work well) Note: Make sure your oranges will fit into the jars you've chosen!
- four oranges
(no bruises or cuts in the skin, smaller oranges fit in jars better)
- two ZipLoc
bags (to hold the oranges that will go in the jars)
- scale (0-500
grams or equivalent)
- microscope
(optional)
- Copy a class
set of the Family Page and about 15 copies
of Data Sheet #1.
- Make an
overhead transparency of Data Sheet #1 and Data
Sheet #2.
- Choose a
location for the center that allows for the display of multiple background
information display pages throughout the investigation. (See Ready
to Print.)
Get Set...
- Share the
oranges with the class. Ask, "What do you think will happen to these
oranges if we leave them in the room for a week?" A month? Three
months? Discuss responses.
- Place two
of the oranges in ZipLoc bags. Place the bagged oranges in jars. Label
the jars with the corresponding orange number. Note: The ZipLoc bag will
make it easier to remove the orange from the jar and record its mass once
decomposition begins.
- Place the
remaining two oranges next to each sealed jar. Do not put these oranges
in a bag or a jar. Label each orange on its skin with the corresponding
orange number.
- Have pairs
of students weigh each orange to find its mass (grams).
Record this information on the Data Sheet #2 transparency, but wait to
share Data Sheet #2 with students until week two.
- Place the
oranges at their designated center in the classroom.
- Place a
clipboard on the center with copies of Data Sheet #1 for informal observation.
Week
2: Small Group Observation and Introduce Data Sheet #2 (15 min.)
Go!!!
- Assign two
or more students to weigh each orange, record observations on Data Sheet
#1, and report findings to the class, including any patterns in the overall
data (i.e., the jarred oranges are beginning to change color, the unjarred
oranges are getting lighter and smaller each week, etc.).
- Introduce
an overhead transparency of Data Sheet #2. Plot data for week one as a
class and discuss.
- Have students
make informal predictions/hypotheses for the following week.
- Display
student observations at the center.
Note: The
teacher or a student should open the bagged oranges each week outside to allow
fresh air to enter the bag. This will prevent slowing of the decomposition
process due to a lack of oxygen.
Weeks
3 to 11: Small Group Observation and Introduce Background Information (15
min. each week)
- Assign two
or more students to weigh each orange, record observations on Data Sheet
#1, and report findings to the class including any patterns in the overall
data (i.e., the jarred oranges are beginning to change color, the unjarred
oranges are getting lighter and smaller each week, etc.).
- Plot new
mass data on the overhead transparency of Data Sheet #2 as a class. Discuss
patterns.
- Discuss
background information as a class, according to the following schedule:
- Have students
make informal predictions/hypotheses for the following week.
- Display
student observations and the weekly background information display page
at the center.
- Assign all
students to write 30 words or more to summarize their learning from the
week's information.
Note: The
teacher or a student should open the bagged oranges each week outside to allow
fresh air to enter the bag. This will prevent slowing of the decomposition
process due to a lack of oxygen.
Note: Denise
Prichard (Clermont Northeastern Middle School) suggested a nice innovation
for this activity. After the fifth week, stop graphing the mass results with
the overhead transparency, but continue having groups of students share weekly
observations. After the final week of observations, have students graph one
or more of the oranges on regular graph paper for the entire period. Have
the students complete all components of the graph (title, labels, number scales).
Encourage a number scale with five gram increments to clearly illustrate the
change in mass. Then have students write a paragraph to explain what they
learned from this activity on the back of their graph.
Week
12: Small Group Observation and Class Data Sheet (15 min.)
- Assign two
or more students to weigh each orange, record observations on Data Sheet
#1, and report findings to the class, including any patterns in the overall
data (i.e., the jarred oranges are beginning to change color, the unjarred
oranges are getting lighter and smaller each week, etc.).
- Display
student observations at the center.
Note: If
you have access to a microscope with 400x magnification, you can view bacteria
cells in the liquid from orange decomposition.
PutItAllTogether
(20 min.)
Take
It Further!
- Discuss the connection
between improper food preparation and the growth of harmful bacteria such
as salmonella that can cause food poisoning.
Record this information on the Data Sheet #2 transparency, but wait to
share Data Sheet #2 with students until week two.