## Bridge Design

Type: Investigation

Theme: Engineering

Grades: 5, 6, 7, 8, 9, 10

Learning Target: Students will learn about three major bridge types while working with ratios and percentages and learning about three common functions. Instructions

Please collaborate with a partner (3 students only). Each student in the group will need to research one bridge type.

This math investigation focuses on precision and accuracy.

1. Challenge: How far can you extend uniform objects over the lip of a table?
1. Locate a set of uniform (same size and dimensions) flat objects that can be stacked (dominoes, craft or popsicle sticks, books, Jenga blocks, etc.).
2. Measure the long side of the object in centimeters.
3. Extend one object over the side of the table. Measure the distance you able to extend it off the table in centimeters? What percentage of the whole length was over the air?
4. Attempt to suspend as many of the objects (stacked) as far as you can over the lip of the table. Measure the distance you able to extend it off the table in centimeters? What percentage of the top object was beyond the lip of the table?
5. Take a photo inline with the table edge.
2. Briefly research one of the three main bridge types: beam, arch, suspension. Write two paragraphs in your own words describing that bridge type. Include at least three resources.
3. Submission: Word document containing the following (you are not required to create a Sway or PowerPoint).
2. Measurements and percentages
Object length: __________cm
One object: Distance over the air: __________cm
One object: Percentage over the air: __________%
Multiple objects: Distance over the air: __________cm
Multiple objects: Percentage of top object over the air: __________%
(We will use the value above to compare among groups.)
3. A photograph of your suspended objects
4. One paragraph explaining why you think your objects extended further when stacked.
Does it matter how the objects are stacked and spaced? Which worked best for you: linear, logarithmic, or exponential?
Does mass of the object matter?
Is there an optimal number of pieces?
5. Your research (each student should research a different bridge type.)

### //table
color("BurlyWood")translate([-100,0,-5])cube([100,100,5]);

// logarithm to the base 10
for(x=[0:1:10]){
y=10*log(x+1);
color( [0.5+sin(10*x)/2, 0.5+sin(10*y)/2, 0.5+sin(10*(x+y))/2] )
translate([-10+y,10,x])cube([10,5,1]);
}

//exponential
for(x=[0:1:10]){
y=pow(1.3,x+1);
color( [0.5+sin(10*x)/2, 0.5+sin(10*y)/2, 0.5+sin(10*(x+y))/2] )
translate([-1.3-10+y,40,x])cube([10,5,1]);
}

//linear
for(x=[0:1:10]){
y=1.8*x;
color( [0.5+sin(10*x)/2, 0.5+sin(10*y)/2, 0.5+sin(10*(x+y))/2] )
translate([y-10,70,x])cube([10,5,1]);
}

### Resources

Exit Ticket
CCSS Math Practice
• I can make sense of problems and persevere in solving them.
• I can attend to precision.
NGSS Crosscutting Concepts
• Structure and Function