Super Structures
[Image of a Lego Zip line]
Objective:
1. Apply elements of structure (i.e. right triangles, reinforced squares,
tetrahedrons, and reinforced cubes) to build structures that are tall and can
hold the weight of dowels and rubber bands.
Prerequisite Knowledge:
NSTA Science Process Skills:
Accessibility: [Specific changes to procedure in blue and in square
brackets]
What You Need:
 Dowels, 2’ long by ½” diameter – 60 per 4
 Dowels, 3’ long by ½” diameter – 12 per 4
 Rubber bands, #33 – 200 per 4
 Frisbee OR other container for rubber bands – 1 per 4
 Dowels, 8” long by ¼” diameter – 60 per 4
 Dowels, 12” long by ¼” diameter – 12 per 4
 Animal, stuffed with 5 pounds of weight OR 5 pound weight – 1
 Animal, stuffed with 3 pounds of weight OR 3 pound weight– 1
 Ankle weights, 1 lb. OR 1 lb. weight – 6
 Foam square, blue construction type, 12”x12” – 1
 Ladder, 6’ - 1
Preparation:
 Write the 3 challenges on the board with their criteria.
 Create a set of: sixty 2’ dowels, twelve 3’ dowels, and ~200 rubber
bands in a container for each group of 4.
 Prepare fifty of the 8” length by ¼” diameter dowel sections, twelve of
the 12” length by ¼” diameter dowel sections, six pencils, 6 ¼” sheets
of graph paper, and small rubber bands for each of the groups.
 Make a square and triangle with the rubber bands and short dowels
before class. Also make a cube, a reinforced on 4 sides cube, a
triangular based pyramid, and a square based pyramid.
What You Do:
Introduction
1. Introduce yourself to students and reveal the challenge. “Using 2 and 3
foot dowels and rubber bands, create one of the following: a dome
that can fit your team under it and support a 5 pound load, a bridge to
cross an 8 foot span and capable of supporting a 5 pound load, or a
tower that reaches 8 feet high and can support a 5 pound load.”
2. Instruct students on rubber band building techniques. Show how to join
2 dowels together, then 3 dowels together by lining the dowels up and
twisting the rubber band back on itself again and again to achieve
tension. Show how to adjust the length by sliding the dowels back and
forth. 2” of overlap is ideal so that pieces can be attached to one
another.
3. Ask, “How far away do you need to be from a 9’ tower to be completely
safe if it falls?” The correct answer is 9 feet. Ask students, “Where do
the workers stand when they build a bridge on the deck or under the
deck?” (On top or on scaffolding that they built.)
4. Explain, “Building anything that stands up is inherently dangerous on
some level because it can fall down. If you notice it falling, get out of
the way. If it falls on you, we have first aid.”
5. Explain, “When you are moving around the room with a dowel, walk
with them as if they are canes, with hands on one end and the other
end pointed down. (Demonstrate the specific behavior.) You are far
more likely to be injured by tripping or being poked with a dowel than
by a structure falling on you.”
Priming
1. Reveal the model square. Using your hands show students what
happens when you press at various points on the square.
2. Reveal the triangle. Using your hands show students what happens
when you press at various points on the triangle.
3. Tell, “Every material has a different response to compression
[squeezing, illustrate with hands] and tension [pulling apart, illustrate
with hands]. It can resist, not resist, or fail. The rubber band resists
tension until it fails. As it is pulled apart it gets hard and brittle. It does
not resist compression. The dowels resist both tension and
compression, but do not resist being bent (torsion) until they fail.”
4. Explain, “By using these shapes we can make things strong that
weren’t strong before. If we can make them strong, we can make them
stand up.” Add a crossbar (12” dowel) to the square diagonally. Press
at various places. Add a 2nd crossbar (12” dowel) to the square. Press
at various places.
5. Option: If time is short, or if students don’t discover them in 15 minutes
or so, consider giving students the reinforced cube and tetrahedron
idea.
6. Reveal the cube reinforced on 4 sides. Ask, “How many squares do
you see?” [6] “How many triangles do you see?” [8] Using your hands
show students what happens when you press at various points on the
partially reinforced cube.
7. Add two 12” dowels to reinforce the empty faces of the cube. Using
your hands show students what happens when you press at various
points on the reinforced cube.
8. Reveal the tetrahedron. Ask, “How many squares do you see?” [0]
“How many triangles do you see? [4] Using your hands show students
what happens when you press at various points on the tetrahedron.
9. Tell, “We’re going to build a model and then build the real thing next. I
will help you with the construction and materials part of the class, but
you will need to figure out how to solve your problems and make your
decisions without fighting. If there’s a disagreement, use rock-paperscissors and move on. If you get confused or don’t know what to do,
then good, that’s part of learning. Try something and see what
happens.”
Model Building Time
1. Introduce the students to the Plan, Build, and Test design cycle. Say,
“You must plan out your structure before building it. This will give you
time to experiment with what works and what doesn’t in a lower stress
situation.”
2. Tell, “The sticks are to build a repeating unit to make your structure out
of that can handle some load. The paper is to draw how they will look
when assembled.”
3. Direct students to raise their hand if they would like to build a: Tower?
Bridge? Shelter? Group students into groups of four, ideally. Groups of
3 or 5 are okay, but others can be too large or small to accomplish the
task.
4. If the students have a complete picture and a partial model they can
begin building.
Note: If a student is having trouble beginning, suggest that they use a
repeating unit of some kind to complete the task at hand.
Building Time
1. Students build their bridges, towers, or shelters during this time. Help
students with materials and supervise their work, but do not intercede
unless it is for their safety. If groups want you to test their structure
early, test it.
2. If a group can’t finish their structure with the dowels provided, they may
have extra materials provided if they can be specific about how many
they need.
3. At the end of the time limit, instruct students to stop building. Measure
the structures with the measuring tape, or ask students to fit within
them first. Then, with students standing at a safe distance, test the
structures by placing the styrofoam platform over their center (use the
ladder for the tower) and place the weighted stuffed animal on it. If the
structure survives for 10 seconds, they have passed the test. Continue
placing weight on the structure until it fails or you run out of weights.
4. Instruct students to disassemble their structures. This takes at least 10
minutes.
5. To reflect, repeat the introduction portion about the triangle and the
square. Ask, “Did you see any triangles and squares in your
structure?” Tell, “Behind the walls of every building you see that is
what they look like.”
6. Show the reinforced cube and tetrahedron again. “Did any of you use
shapes like these in your structure?” “Look for these shapes in
structures that you see.”
7. Thank the students for their time and dismiss them.
Student Questions:
There are no written student questions for this activity.
Differentiations and Accommodations:
1. Increase the number of attempts students get. The dowel sets can be
used multiple times for students building one structure, and then trying
to build another. This gets students away from only building towers.
2. Increase the size requirements of the structures. This can increase the
challenge substantially. For towers a tall, safe ladder for student use is
required. Students will need to strengthen their structures by more
elaborate means.
3. Show students great feats of architecture in the priming section, like
the Eiffel Tower, the Great Pyramids, the Coliseum, and modern
stadiums. This can have the effect of copycat creations, which are
okay.
4. Class works on a structure together. The planning for this section will
require some guidance from the teacher and agreement from the
students. Keep students in smaller working groups and decide on the
size of the intersections beforehand so that the structures can fit
together. This project will need space either outside or in a small gym.
The outside of the structure can be covered in paper or cardboard and
decorated for further effect.
NGSS Alignment:
K-2-ETS1-1; K-2-ETS1-2; K-2-ETS1-3; 3-5-ETS1-1; 3-5-ETS1-2; 3-5-ETS13; MS-PS2-2
CCSS Alignment:
W.2.8; MP.2; MP.5; W.5.7; W.5.8; W.5.9; RST.6-8-3; WHST.6-8-7