Step 8: Redesign. After all the groups presented their findings,
students then individually redesigned the facilities. Students used
their knowledge of their group’s results, as well as information learned
through other group presentations, to justify changes made as they
redesigned their prototype. Because of time limitations, students only
had the opportunity to sketch their redesigned prototypes in their
individual design portfolios. (If time permits, students can go through
the engineering design cycle again and come up with a group prototype and retest their new design.) The teacher then concluded the unit
by discussing the benefits of the engineering design process and how
this process could be used to solve other problems in society. (The
teacher should stress that students can always optimize their design
even if they were successful the first time. This should be done with
guided questioning so as not to give away potential changes from
the teacher’s perspective.)
Students were assessed on their individual design portfolios, as well
as on their group presentation. The evaluation rubric for the group
presentation is provided in Table 1. Students should be aware that
their grade does not depend on the success or failure of their quarantine structure, because one of the important components of the engineering design is the emphasis on learning from failure. One option
is for teachers to award extra credit to successful structures.
In addition, students were assessed on biology content knowledge
and engineering design knowledge both before and after they participated in the unit. The biology content assessment consisted of questions regarding slime molds, and the engineering design assessment
contained open-ended questions about the engineering design.
Students also took a survey prior to and following the engineering-design-integrated unit that measured their perceptions of engineering
design. Pre/post test results for all assessments are provided below.
Summary & Results
Overall, the purpose of this lab activity was to teach students the
Suggestions for Future Teaching
characteristics of slime molds and related biological principles using
the engineering design process. More than 100 students received
instruction in this unit. Students were able to learn the engineering
design process and apply it to solve an authentic, real-world prob-
lem from their biology classroom and also learn how they could
potentially apply it to solve other problems as well. Most groups
were successful in quarantining the slime mold from the non-inocu-
lated oats. Students demonstrated sound understanding of the engi-
neering design process through their design portfolios. Student
responses to pre/post test items regarding biology content knowl-
edge and engineering design knowledge were scored on a scale
of 0–2 points (0 = completely incorrect, 1 = partially correct, and
2 = completely correct). A paired-sample t-test revealed a statistically
significant difference between pretests and posttests in students’
biology content knowledge (t70 = 12.09, P < 0.000) and the engi-
neering design process (t70 = −12.97, P < 0.000). Furthermore, after
participating in the engineering design unit, students’ perceptions of
engineering design increased by a statistically significant amount
(t67 = −7.71, P < 0.000). Overall, these findings suggest that teaching
a science concept, such as slime molds, through engineering design
may increase students’ content knowledge in science and engineering
design as well as their perceptions of engineering design.
While this unit was extremely successful in teaching students biology concepts and engineering design, it was created to help students
learn biology content knowledge prescribed in our state standards
using engineering design. When restructuring this unit for future
use, teachers should consider building in an extra day to explicitly
address the science content objectives they wish to achieve. This unit
provides a great opportunity for students to build background
knowledge for key vocabulary words, such as eukaryotic, prokaryotic,
classification systems, and cellular organelles. We recommend introducing these terms as they relate to slime molds, to help students
make connections with the vocabulary.
Connecting to NGSS
Table 2 shows how the activities in this unit are connected to NGSS
core ideas, science and engineering practices, and crosscutting concepts.
Table 2. Connecting to the Next Generation Science Standards.
HS-LS1 Structure and Function
HS-ETS1 Engineering Design
HS-LS1-2. Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific
functions within multicellular organisms.
HS-LS1-3. Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.
HS-ETS1-1. Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that
account for societal needs and wants.
HS-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems
that can be solved through engineering.
HS-ETS1-3. Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a
range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.