Evidence of gains in student understanding of
science through the use of GEMS.
Earth, Moon, and Stars Research Studies: An extensive
body of research supports both the approach used and the level of educational
effectiveness achieved by the GEMS unit Earth, Moon, and Stars.
This research, including related studies and publications, contains
strong evidence of gains in student understanding of two importance
science conceptsgravity and the spherical shape of the Earth.
Based on what research has determined to be major student misconceptions,
the GEMS unit was developed and tested, then studies were conducted
to determine the extent to which the designed unit made a measurable
difference in student learning. Subsequently, lessons learned from this
research have been applied to several other GEMS units, including Moons
of Jupiter and the upcoming Messages from Space: The Solar System
and Beyond (in press).
The study involved the application of Nussbaums Earth Notions
Classification Scheme to results of testing of 159 boys and girls from
public schools in San Francisco, and the relation of these results to
research conducted in Nepal, Israel, and Ithaca, New York. The classification
scheme was itself subjected to rigorous analysis (see under "Results/Validation
and Refinement of the Earth Notions Classification Scheme, page 211217)
with statistical and prediction analysis, resulting in a suggested refinement
to include an additional notion between Notions III and IV in Nussbaums
classification. Results were analyzed based on age and grade, and in
relation to previous research, and confirmed that children interpret
information about the spherical Earth and gravity in terms of their
own models of the world, and that these interpretations, while representing
reasonable "alternative frameworks" from the childs
point of view, require considerable additional learning experience to
be transformed into accurate scientific conceptions.
The GEMS unit Earth, Moon, and Stars was intentionally designed
and developed to help students overcome the misconceptions that were
"unearthed" by the series of research studies, by engaging
students in observations of the sky, and having them consider how alternative
models can best explain their observations. The GEMS unit prominently
includes a pre- and post-questionnaire, "What Are Your Ideas About
the Earth?" which builds upon the experience of the previous studies,
and in turn became a central element in the subsequent research studies
of educational effectiveness of the GEMS unit. (Aside from these more
formal studies, teachers are also instructed in the unit about how to
use the questionnaire provided as a pre-test and post-test to assess
the degree to which their students have comprehended modern scientific
concepts about the Earths shape and gravity. The questionnaire,
with actual student work, and instructions to the teacher on its use,
are featured as a case study in the GEMS assessment handbook.)
Since the GEMS unit was developed, tested, and published, additional
studies have evaluated the extent to which the activities in the unit
succeed in overcoming student misconceptions. "Unraveling Students
Misconceptions about the Earths Shape and Gravity," details
a study involving 539 students from 18 classrooms in 10 different states.
The experimental treatment was the GEMS unit, Earth, Moon, and Stars.
The primary experiment was a treatment-group-only design, in which teachers
(trained in the use of the questionnaire assessment instrument at a
summer institute sponsored by NSF) administered the same test to all
students before and after the treatment. The purpose was to determine
the impact of the treatment on students understanding of the Earths
shape and gravity concepts. Data were analyzed in three age groups (4th
and 5th graders; sixth graders; and 7th and 8th graders). As expected
from previous studies, on the pretest all classes displayed a wide variety
of conceptions about these concepts. After the unit, however, the number
of subjects who held misconceptions was far fewer. Chi-square analyses
showed that a significant number of students at all grade levels shed
their misconceptions concerning both the Earths shape and gravity.
A surprising finding was that younger subjects responded more positively
to the experimental treatment than older students, so that, after instruction
in the GEMS unit, fourth and fifth graders were as knowledgeable as
seventh and eighth graders concerning the Earths shape and gravity.
While the GEMS unit was tested and found effective from Grades 48,
the study suggests that this may indicate that presentation of the unit
at the earlier grade levels may be particularly beneficial.
As Table 4 on page 279 of the Sneider Ohadi article depicts, percentages
of students who demonstrated increased understanding of the Earths
shape before and after the GEMS unit went from 24% to 72% for Grades
45; from 27% to 45% for Grade 6; and from 38% to 62% for Grades
78. The percentage of students understanding gravity went from
7% to 67% for Grades 45; from 15% to 47% for Grade 6; and from
30% to 60% for Grades 78. In conclusion, the authors state: "
The
concepts selected for study by the studentsthe earths spherical
shape and gravitywere considered by many researchers to be of
fundamental importance in allowing students to understand the modern
scientific explanations of a wide variety of phenomena, such as the
daily cycle of the sun, phases of the moon, and seasons. These findings
were bolstered by a full-experimental, control-group study
supporting
the conclusion that the constructivist teaching unitEarth,
Moon, and Stars, from the GEMS seriesenabled large numbers
of students to unravel their misconceptions and construct a more accurate
model of the world." (Emphasis added.) These studies, and additional
studies and articles referenced below, have also had a significant impact
on further curriculum development in GEMS, in particular on the Moons
of Jupiter and Messages from Space units (see Sneider articles
in collaboration with Varda Bar and others cited below on gravity in
space, weight and free fall, and gravity and air). As the Sneider Ohadi
study progressed, insights gained were taken into account as the GEMS
assessment handbook was developed and as revisions of Earth, Moon,
and Stars were published.
C. Sneider and S. Pulos. "Childrens Cosmographies:
Understanding the Earths Shape and Gravity." Science Education
67 (2) (1983): 205-221.
C. Sneider and S. Pulos, Evangeline Freenor, Joyce Porter, and Betty
Templeton, "Understanding the Earths Shape and Gravity,"
Learning 86, Vol. 14, No. 6, February, 1986, pages 4347.
C. Sneider and M. Ohadi. "Unravelling Students Misconceptions
About the Earths Shape and Gravity," Science Education 82
(1998) pages 265284.
C. Sneider, Earth Moon and Stars GEMS teachers guide, Lawrence
Hall of Science, 1986, 1989, 1992, 1994, 1996, 1998.
C. Sneider with Varda Bar and Nathalie Martimbeau, "What Research
Says: Is There Gravity in Space?" Science and Children, April 1997.
C. Sneider with Varda Bar, Barbara Zinn, and Rivka Goldmuntz, "Childrens
Concepts About Weight and Free Fall," Science Education, Volume
78, Number 2, pages 149169, 1994.
C. Sneider, "Does Gravity Need Air?: A Force That Holds the Universe
Together," GEMS Network News, Fall/Winter, 1993, pages 2629.
C. Sneider, "Shape of the Earth Assessment Task for Earth, Moon,
and Stars," GEMS Network News, Fall/Winter, 1993, pages 3031.
Barber, J et al, Insights and Outcomes: Assessments for Great Explorations
in Math and Science, "Case Study Using Pre-Post Testing, What
Are Your Ideas About the Earth from Earth, Moon, and Stars,"
pages 102109.
Nussbaum, Joseph, "The Earth as a Cosmic Body," in R. Driver,
E. Guesne, A. Tiberghien (editors) Childrens Ideas in Science,
Open University Press, Philadelphia, 1985.
The Galaxy Classroom Project (Pilot Program 1991-1995) funded by
Hughes Aircraft and the National Science Foundation: The Galaxy
Classroom Project is a multimedia, year-long program for K5 students
in classrooms nationwide. A main goal of the K2 component is to
impact student learning of the science/mathematics concepts and processes
of observing, comparing, communicating, properties of solids and liquids,
structure/function of living organisms. The Pilot Program consisted
of a core classroom curriculum from the GEMS and FOSS projects of LHS
with two series of interactive television programs designed to incorporate
the science and math concepts emphasized in the classroom program. Family
home activities and classroom activities involving fax and the Internet
are also included. The program is currently being conducted statewide
in Georgia, in selected districts in California, elsewhere in the United
States, and in Canada. Since 1995, the Project revised their classroom
curriculum to include only GEMS units. The GEMS units for the K2
program include Terrarium Habitats, Liquid Explorations,
and other GEMS early childhood units. The 3rd through 5th grade program
focuses on Bubble-ology, Oobleck, Chemical Reactions,
Investigating Artifacts, and five others. As is typical of GEMS,
several of these units also have a strong mathematics component. The
executive summary of the final report of the Galaxy K2 program
show student gains in learning key concepts, improvements in teacher
instructional practices, and an increase in curiosity of students. The
evaluation gathered quantitative data on GALAXYS impact on student
learning through pre-post tests of observation skills and an assessment
of the science content presented. The report also states: "Teacher
reports and evaluation results confirm that most students understood
the concepts of the two GALAXY themes (recognizing and comparing the
properties of various liquids, solids, and mixtures and identifying
and comparing the characteristics and features of insects)." The
report adds, "GALAXY first and second graders exhibited a striking
and statistically significant growth in curiosity when compared to their
non-GALAXY peers." (Page1, Far West Laboratory, Final Report.)
The Far West Laboratory for Educational Research and Development (currently
West Ed Laboratory) of San Francisco conducted the evaluation for the
Galaxy Classroom Project. It was directed by Dr. Gloria Guth.
PEACHES I Project, funded by the National Science Foundation:
In 1994, the Primary Education for Adults, Children, and Educators in
Science (PEACHES) Program completed a 4-year teacher enhancement project
funded by NSF to improve the science and math teaching skills of preschool
teachers and day care providers. The project conducted two 60-hour,
4-unit courses for early childhood educators based on 10 curriculum
units developed by the program that contained developmentally appropriate
science/math activities for 4-6 year olds. Six of the ten units, Tree
Homes, Ant Homes Under the Ground, Ladybugs, Eggs
Eggs Everywhere, Penguins and Their Young, and Mother
Opossum and Her Babies are part of the GEMS programGEMS re-tests
and publishes PEACHES trial versions, which then become GEMS units.
In the final evaluation, Project Evaluator Dr. Bo De Long conducted
a study to measure changes occurring in preschoolers knowledge
about life science as a result of the project curriculum. Eighteen preschool-age
children (from 3.4 years to 5.0 years) were administered individual
interviews regarding their knowledge of and familiarity with the diets,
habitats, and defense behaviors of various pond-, tree-, and ground-dwelling
animals featured in the curriculum. These interviews consisted of open-ended
questions designed to elicit knowledge about these animals as well as
reveal the kinds of reasoning skills the children were employing when
talking and thinking about life science. Students were administered
the interview as a pre-test approximately one week prior to beginning
the units (Tree Homes, Homes on the Ground, Ant Homes
Under the Ground, and Homes in a Pond) and then again as
a post-test approximately one week following completion of the units.
The total time between pre- and post-tests was approximately three months.
A control group from the same school was administered the same pre-
and post-test separated by a similar three month interval. This group
was included in order to ensure that any changes observed in the childrens
quality or quantity of factual knowledge as well as changes in the reasoning
skills they applied were due to exposure to the curriculum rather than
to expected developmental changes or learning effects due to testing.
The original control group included twelve three- and four-year-olds,
divided equally by sexhowever, all but four females dropped out
of the study due to moving, changing schools, or entering a new class
where the units were being taught.
Childrens understanding and retention of some of the content
taught was measured by how well they could identify six animals presented
in the units and by evaluating their responses to questions about the
diet, habitats, and defense behaviors of those animals. Students were
first given a dichotomous score (correct/incorrect) for their knowledge
of the identity and behaviors of these six animals. The findings indicate
that children exposed to the curriculum did, in fact, learn and retain
content about the behaviors of the animals they are studying.
Table 6. Mean scores for content evaluation pre and post tests for
treatment group and computed values of t for within-subjects matched
group comparisons
Content area |
Mean score
pre test |
Mean score
post test |
Computed value
of t |
Identification |
4.3 |
5.0 |
2.140* |
Habitat |
3.6 |
4.6 |
2.769* |
Diet |
1.7 |
3.3 |
3.531** |
Defenses |
3.8 |
5.2 |
4.213*** |
Critical value of t at 17df = 2.110, p< .05*; 2.898,
p< .01**; 3.965, p< .001***
Table 7. Mean scores for content evaluation pre and post tests for
control group
and computed values of t for within-subjects matched group comparisons
Content area |
Mean score
pre test |
Mean score
post test |
Computed value
of t |
Identification |
3.5 |
4.5 |
2.40 |
Habitat |
3.5 |
3.5 |
1 |
Diet |
1.5 |
2.0 |
.775 |
Defenses |
4.75 |
5.75 |
2.45 |
Critical value of t at 3df = 3.182, p< .05*
Note: The accuracy of teachers perceptions that children
became more sophisticated in some of their cognitive skills because
of the PEACHES/GEMS units was also evaluated. While sufficient evidence
was not found for this, the great majority of teachers reported that
their students became better reasoners after they experienced
the PEACHES/GEMS units, so this may merit further study. Insufficient
evidence was also found for another teachers reportthat
the units had a positive impact on sorting and classification skills.
Again, a longer-term study might reveal qualitative gains in classification
skills that were not demonstrated in this short-term evaluation.
Seabrook GEMS Site Studies. Myra Luciano of the Seabrook, Texas
GEMS Network Site has conducted two studies. In the first, in 1997,
on the GEMS unit Build It! Festival at her elementary school,
she conducted a performance-based evaluation with a random sampling
of 19 second and 24 fifth graders to determine whether or not students
demonstrated improved learning in the areas of patterns, shapes, and
spatial sense. The compiled data shows considerable improvement in recognition
of shapes and spatial sense for both grade level groups. In 1999, Ms.
Luciano conducted a study on the GEMS unit Animal Defenses, with
30 1st graders in the treatment group and 16 1st graders in the control
group. The treatment group of 30 participated in the Animal Defenses
unit the year before, when they were Kindergarteners. The 16 in the
control group had never been exposed to the GEMS lessons. Both groups
were asked to record all the animal defenses they were familiar with.
The data by Ms. Luciano shows that the treatment groups median
score was 4 words as compared to the median score of 1 word for the
control group. The analysis by Eric Crane, School of Education, U.C.
Berkeley indicates that the scores are significant if student factors
such as age, grade, and teachers are taken into account. Further conversation
with Ms. Luciano indicated that students in both groups were randomly
distributed over three first grade classrooms at one school.
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