What Activities Do Students Do in Their Science Lessons?
Because it can affect pedagogical strategies, class size is shown
in Exhibit
6.7. Teachers’ reports on the size of their eighth-grade
science class reveal that across countries the average was 31 students,
but there was considerable variation even among the higher-performing
countries – from 43 students in Korea to 20 in Belgium (Flemish).
Average class size was relatively uniform across all of the Benchmarking
entities, ranging from 23 to 32 students. The relationship between
class size and achievement is difficult to disentangle, given the
variety of policies and practices and the fact that smaller classes
can be used for both advanced and remedial learning. It makes sense,
however, that teachers may have an easier time managing and conducting
more student centered instructional activities with smaller classes.
Extensive research about class size in relation to achievement indicates
that the existence of such a relationship is dependent on the situation.(4)
Dramatic reductions in class size can be related to gains in achievement,
but the chief effects of smaller classes often are in relation to
teacher attitudes and instructional behaviors. Also, the research
is more consistent in suggesting that reductions in class size have
the potential to help students in the primary grades. The TIMSS 1999
data support the complexity of this issue. Four of the five highest-performing
countries – Chinese Taipei, Singapore, Japan, and Korea –
were among those with the largest science classes. Within countries,
several show little or no relationship between achievement and class
size, often because students are mostly all in classes of similar
size. Within other countries, there appears to be a curvilinear relationship,
or those students with higher achievement appear to be in larger classes.
In some countries, larger classes may represent the more usual situation
for science teaching, with smaller classes used primarily for students
needing remediation or for those students in the less-advanced tracks.
Exhibit
6.8 presents a profile of the activities most commonly
encountered in science classes around the world, as reported by science
teachers. On average internationally, the most common activity was
teacher lecture (24 percent of class time), followed by students conducting
experiments (15 percent) and teacher-guided student practice (14 percent).
Re-teaching and clarification of content and procedures, student independent
practice, tests and quizzes, and teacher demonstrations of experiments
each occupied 10 percent of class time. In general for the United
States as a whole and the Benchmarking entities, teachers’ reports
on the frequency of these activities matched the international profile.
According to US science teachers, class time is spent as follows:
19 percent on lecture style teacher presentation; 23 percent on teacher-guided
or independent student practice; 17 percent on students conducting
experiments; eight percent on teachers demonstrating experiments;
nine percent on re-teaching and clarification; nine percent on tests
and quizzes, eight percent on homework review; six percent on administrative
tasks; and three percent on other activities.
As shown in Exhibit
6.9, most students internationally (80 percent on average
in general-science countries) agreed with teachers’ reports about
the prevalence of teacher-guided activities, saying that their teachers
frequently showed them how to do science problems. Approximately 70
percent of the students in the United States overall and in most of
the Benchmarking entities reported this also. According to students,
working independently on worksheets or textbooks also occurred frequently
internationally (56 percent), and was even more pervasive throughout
the Benchmarking entities, where between 70 and 85 percent in most
entities reported doing this activity almost always or pretty often.
As for working on science projects, the Benchmarking entities typically
were above the international average (51 percent), ranging from 49
to 77 percent.
Compared with students internationally, eighth graders in each of
the Benchmarking jurisdictions and in the United States overall reported
an unusually large amount of classroom time devoted to working on
homework. Internationally, 51 percent of the students reported frequently
discussing their completed homework in science class. The figure for
the United States was 63 percent, and it ranged from 52 percent in
Texas to 82 percent in Naperville for the Benchmarking jurisdictions.
A slightly greater difference was evident for frequently beginning
homework in class – 41 percent internationally compared with
57 percent for the United States. In the Benchmarking jurisdictions,
from 41 to 74 percent of the students reported beginning their homework
in class almost always or pretty often.
As might be anticipated, students reported that use of the board
was an extremely common presentational mode in science class (see
Exhibit
6.10). On average internationally for the general-science
countries, 86 percent of students reported that teachers used the
board at least pretty often, and 42 percent reported that students
did so. Using the board seems to be less common in the United States,
especially for students (29 percent). In the United States, use of
an overhead projector is a popular presentational mode, especially
for teachers – 59 percent compared with 32 percent internationally.
This mode was used frequently for more than 70 percent of the students
in Maryland, North Carolina, Oregon, South Carolina, Texas, the Academy
School District, Guilford County, Montgomery County, and Rochester.
Use of a computer by the teacher to demonstrate ideas in science was
more prevalent in the US (20 percent of students) than internationally
(10 percent), and among Benchmarking entities ranged from 12 percent
in Chicago and Guilford County to 28 percent in Jersey City and Montgomery
County.
Effective science instruction requires the teacher to guide, focus,
challenge, and encourage student learning. Problem-solving activities
typically call upon students to use higher-order thinking skills.
To examine the emphasis on reasoning and problem-solving in science
class, TIMSS created an index of teachers’ emphasis on scientific
reasoning and problem-solving (ESRPS). As shown in Exhibit
6.11, the index is based on teachers’ reports
about how often they asked students to explain the reasoning behind
an idea, represent and analyze relationships using tables, charts,
and graphs, work on problems for which there is no immediately obvious
method of solution, write explanations about what was observed and
why it happened, and put events or objects in order and give a reason
for the organization. Students were placed in the high category if,
on average, they were asked to do these activities in most of their
lessons. The medium level represents students asked to do these activities
in some to most lessons, and students in the low category did them
only in some lessons or rarely.
On average internationally, 16 percent of students had teachers who
placed a high emphasis on scientific reasoning and problem-solving,
ranging from four percent in Belgium (Flemish) to about one-third
in Japan among the comparison countries. While the emphasis on scientific
reasoning and problem-solving was associated with achievement in some
countries, there was no strong or consistent relationship internationally
or across entities. There was tremendous variation among the Benchmarking
participants on this index, ranging from 63 percent of students in
the high category in Naperville to nine percent or less in Chicago,
Rochester, the Michigan Invitational Group, and Idaho.
Exhibit
R3.7 in the reference section shows the percentages
of students asked in most or every lesson to engage in each of the
activities included in the problem-solving index. The most common
problem-solving activity was for teachers to ask students to explain
the reasoning behind an idea. On average internationally, 68 percent
of students had teachers who asked them to do this in most or every
lesson. On average also, a majority of students (52 percent) were
asked to write explanations about what was observed and why it happened
in most or every lesson, but only 15 percent were asked to work on
problems for which there was no immediately obvious method of solution.
In the United States and among Benchmarking participants generally,
teachers more often asked students to explain the reasoning behind
an idea (80 percent of students in the United States, and up to 100
percent in Naperville), but otherwise approximated the international
averages.
The choices teachers make determine, to a large extent, what students
learn. An important aspect of teaching science is the emphasis placed
on scientific investigation. In order to measure this, TIMSS created
an index of emphasis on conducting experiments in science classes
(ECES), shown in Exhibit
6.12. The index is based on students’ and teachers’
reports of the frequency of the teacher demonstrating experiments
and the students conducting experiments or practical investigations.
A high level indicates that the teacher reported that at least 25
percent of class time is spent on the teacher demonstrating or students
conducting experiments, and the student reported that these occur
almost always or pretty often. A low level indicates that the teacher
reported that 10 percent or less of class time is spent on the teacher
demonstrating or students conducting experiments, and the student
reported that these occur once in a while or never. The middle category
includes all other combinations of responses.
Internationally on average, 38 percent of students in countries with
general/integrated science were in classes with a high emphasis on
experiments, ranging from two percent in Italy to 78 percent in Hong
Kong. There was great variation among the Benchmarking participants
also, from a high of 79 percent in Naperville to a low of 17 percent
in the Delaware Science Coalition. In general, lower percentages of
students in the high category were found in the countries with separate
sciences, but this varied across science subjects, with the greatest
emphasis on experiments in the physical sciences. Earth science had
the least emphasis on experiments. Across countries, 52 percent of
earth science students were in the low category, but only 21 percent
of students in biology, five percent in physics and chemistry, and
three percent in general/integrated science had classes with low emphasis
on experiments.
Exhibits
R3.8 and 3.9 in the reference section summarize students’
responses to the questions on the frequency of teachers demonstrating
and students conducting experiments that were included in the index
of emphasis on conducting experiments. On average internationally,
71 percent of students in general/integrated science reported that
their teachers demonstrate experiments almost always or pretty often.
Only 29 percent of Italian students reported that their teachers did
so, compared with 91 percent of the students in England. The United
States and the Benchmarking participants generally were close to the
international average. Among separate-science countries, teacher demonstrations
of experiments were reported most often in chemistry (68 percent)
and physics (61 percent), and less frequently in biology (42 percent)
and earth science (19 percent).
Students’ reports on the frequency with which they conduct experiments
or practical investigations in class show a similar pattern across
science subjects but a lower frequency than for teachers’ demonstration
of experiments. Internationally, 57 percent of students in countries
with general/integrated science reported that they do an experiment
or practical investigation almost always or pretty often. Across countries
with separate sciences, only 15 percent of the students in earth science,
27 percent in biology, and 39 percent in physics and chemistry reported
doing experiments this frequently. In the United States, 65 percent
of students reported frequently doing experiments or practical investigations,
and among Benchmarking participants the percentage ranged from 44
percent in Chicago to more than 85 percent in the Academy School District,
First in the World, and Naperville.
Teachers were not asked about the emphasis placed on using things
from everyday life in solving science problems, but students were
(see Exhibit
R3.10). In most of the countries, students reported
a moderate emphasis on doing this type of problem in science class.
Almost half (49 percent), on average internationally, said these activities
occur once in a while or pretty often in science class. The figures
were comparable for the United States and most Benchmarking jurisdictions.
More than half the students in Connecticut, Maryland, North and South
Carolina, Chicago, the Fremont/Lincoln/Westside Public Schools, Guilford
County, Jersey City, Miami-Dade, Naperville, and Rochester reported
that they use things from everyday life in solving science problems
almost always or pretty often.
