Welcome to the Arch page!

Arches of the World

Here's a collection of some arches you may have seen and some that may be new to you.  The idea is that arches are all around us.  Start watching.  What natural and artificial (people-made, that is) arches can you find?

Have you seen this arch before?  It's probably among the most recognized of all the people-made arches in the world.

Here's a whole series of arches that you may have seen once or twice before.  If you've ever actually been there, that's even better!

The arches we want you to see in this photo are those formed by the graceful sweep of the supporting cables of the suspension bridge (this is the Golden Gate Bridge, in case you were wondering).  These arches are called "catenary arches."  They represent the natural shape that forms when something such as a rope, a chain, or the suspension cables of a bridge drape between two points.  Our project focuses on building catenary arches.  For an upright version, picture the Gateway Arch in St. Louis.

Just for fun, here's another series of arches that you may have seen once or twice before...

And here's a type of arch that's near and dear to so many of us.   Well, OK, perhaps this arch in particular is only near and dear to Jessica, but you know what we mean.

But enough of looking at arches, it's time we got busy building arches!

Building Our Desk-Top Arches

We began this project with the intention of building catenary arches that would stand on top of a desk.  A catenary arch is one that distributes the forces upon it smoothly throughout the curve of the arch.   Therefore, once the keystone, or top piece of the arch, is put in place between the two ascending sides, the arch will support itself.

Our arches were drawn on paper, patterns made from those drawings, and then pieces were cut from corrugated cardboard boxes.  We glued the pieces together with regular white glue (though eventually changed to using a hot-glue gun), and assembled the arches by stacking the pieces on top of each other without any glue or fasteners.

We started out by drawing a grid of 5cm squares on large pieces of paper.  After drawing a baseline, we used the 3-4-5 method to draw uprights that were perpendicular to the baseline.  From there, we marked off 5cm increments across the baseline and the uprights to form our grid of 5cm x 5cm squares.

Each of our three groups drew two grids.   One would be used for plotting the profile of the arch and the other would be used for plotting the taper of the arch.  The grids were then held up against the wall, a level placed across the top line of the grid to be sure the grid was level, and then taped into place.  In the picture below you'll see Tiffany and Jessica doing some of the calculations with the grid sheets taped to the wall.

On each grid, three arches were plotted.  The top of the first arch was 60cm below the baseline.  We then plotted a slightly narrower arch within that first one, and then a slightly larger arch outside of the first one.  We did this because our arches were going to be three dimensional.

We used a length of chain held at two points along the baseline to form the arch.  We were going to use a length of clothesline, but a short segment of line is not quite flexible enough.  Instead we used lengths of chain such as that in the photograph below.  The chain is not expensive and can be purchased at most any hardware store.

We eventually found that the best approach was to tape the chain to the grid at the two points where it met the baseline, and then very carefully (so that the chain didn't move) trace the arch that it formed.   We repeated this process two more times so that three arches were drawn on the grid with one arch (the backbone) drawn in between the other two arches (the inside and outside of the arch).  It took some practice to draw the arches without moving the chain.   In the picture below on the left, Grady is tracing in the "backbone" of an arch.  The picture on the right shows Crystal and Lauren tracing the profile of their arch.  This drawing allowed us to taper the arch as it goes from bottom to top.   It makes for a very sleek arch!

With the arches drawn, we measured the length of the center arch by draping the chain over it again, marking the two points where it touched the baseline, and then straightening out the chain and placing it against a meter bar.

The next step was to divide the length of the "backbone" arch by 11.  We did this so that our arches would have five segments going up each side and a keystone at the top - a total of 11 pieces.   This was not some sort of magical number, just the one we chose.

We made a 90 degree angle tool out of some manila folder cardboard.  After cutting two short lengths we placed them on the grid on our paper cutter to be sure they were at right angles to each other.  A little bit of glue was used to keep them together.

We placed the tool with its long edge crossing the points we plotted along the backbone (dividing it into 11 pieces) so that the corners of the base of our tool touched the backbone on either side of the plotted point.  This allowed us to draw a line across all three arches that would define the edges of each segment of the pattern we needed to draw.  The patterns, by the way, will be available on the "Plans" portion of this page shortly.

The pictures below show Shneca, Tiffany, and Jessica getting to work cutting out the pieces of the arches.  The white papers you see are the patterns they drew.

Once all of the pieces were cut out, each group got to work assembling the segments of the arch.  Each segment consisted of a profile piece (those are the pieces in the picture above that form the arch), a cross piece to give it stability, and a top and bottom piece.  The picture below shows Crystal and Lauren starting the glue-up process on their arch.

And before long, the first arch was standing!

And this event was followed shortly thereafter by the standing of Grady and Shneca's arch, only to be followed up by the arch built by Jessica and Tiffany.  As you'll see in the next section, Building the Floor Model, we went on to enlarge the patterns from the desk-top arches to make an arch that stood more than 2 meters tall!

You'll see all three arches assembled in front of the big arch in the next section.  We'll also provide photos of enlarging the patterns and assembling the arch.

Building the Floor Model

The desktop arches stood about 60cm tall.  That was nice, but we were after something more dramatic - something that kids in elementary school would really remember building.  So, once we had a set of patterns for each piece of the arch, we made copies of those patterns on transparencies.   In the picture below you'll see Lauren and Crystal enlarging the patterns by projecting them on the wall using an overhead projector.  With a clean sheet of paper taped to the wall, they would set up the projector so that the image was projected straight onto the wall (avoiding the distortion that results when the image is projected at an angle).  They then moved the projector closer to or further away from the wall until the dimensions of the image were three times the size of the original pattern.

We made full-size patterns of each piece.  After cutting out the patterns, we used a glue stick (drawing a glue line around the perimeter of the pattern) to adhere the patterns to pieces of corrugated cardboard.  All together we had 44 pieces to cut out.  It takes a little time but by now we were getting pretty used to it.  It also helped that everybody had seen that the smaller arches actually stood up!

The larger pieces were interesting to see!

As some of our group were cutting out pieces, others were assembling the segments using a hot-glue gun.   You may or may not want to use the hot-glue depending upon the students you have.   You could also use regular white glue, as we did on the smaller arches.  In any case, as segments were completed they were moved to our front porch for the first attempt at stacking it all together.

You can see already that a life-sized arch will be an impressive sight!  With everybody in on the act, the sides of the arch go up.

Remember, we don't fasten the segments together in any way.  The two sides of the arch will fall in unless someone holds it up - or until we put the keystone in place.

We're pleased to report that our arch stood quite well all on its own, as you can see in the next picture.

It's only fair that we tell you that cardboard arches are susceptible to high winds.  For that reason, we moved the whole show indoors to take the group photo below.  Shneca was not there for the photo, but you will see the rest of our smilin' class: Grady, Crystal, Lauren, Jessica, and Tiffany.

Plans and Ponderings

We hope to eventually post the plans we drew for the arches here on the web page.  At that point you can download them and work from our dimensions or draw a new version of your own.  In the meantime, if you'd like a copy of them for your class (a set requires thirteen pages), contact me at eebert@coker.edu.

It will also be our pleasure to provide any suggestions or help along the way if you and your students should decide to build the arch.

Our class discussed this project as something that a teacher might do over the course of a year, or perhaps over several months.  It provides many opportunities for integrating the curriculum as well as doing various investigations in science.  We just had the time available in one semester while also completing all of our science education topics, and so it was kind of rushed for us.  You may find that it is something that can be broken down into a number of work sessions that you can schedule over several months.

The materials were nothing more than corrugated cardboard, construction paper, some glue, the chain, scissors (or utility knives, depending on your situation), and meter bars.  Cost is minimal.

We had hoped to build another arch that would have been about six times the size of the original arches, but just ran out of time.  We think that elementary students would be very much impressed with the arch you've seen on this page but we still think it would be interesting to go higher if circumstances allow.  We were also rather conservative in the size of the arch from base to base.  You may want to increase that distance to make an even more impressive arch.

Another idea we have in mind is to combine the patterns from each segment and draw them out as a fold-up plan.  That is, one could draw a pattern for the segment that when folded up would yield a segment "box."  The various boxes would then stack one on top of the other just as our segment "skeletons" do.  It would be an interesting exercise in measurement and spatial relationships - not to mention the whole arch part as well.

We hope you have found our arch project interesting!  If we can be of assistance in getting an arch started in your classroom, let us know!

Arch Update

We are happy to report that copies of the plans and directions have been sent to quite a number of folks all around the country - and one set went to Canada!  Pictured below are two arches built by Anne-Marie.  You'll notice that the sections of the smaller arch have been enclosed giving it the "block look" rather than the "skeleton look."  Great job, Anne-Marie!

Building Arches at the NSTA National Convention

"Arch-o-mania" hit the NSTA 2005 National Convention in Dallas at a session held on Saturday afternoon.  The intrepid folks you see here not only made it to a session scheduled late in the day, but they were still there half an hour after our allotted time had expired!

We began by avoiding a lot of lecturing and instead jumped right into the building of the table-top arches.  Within a few minutes both groups had glued up and assembled the pre-cut kits that were provided.  At that point we started discussing some of the details of plotting and building the arch, along with ideas for integrating such a project into the broader curriculum. 

Just about the time when folks were thinking 'this is nice, but where's the BIG arch?' we shifted gears and brought out the large cardboard.  One group began work on the big arch, the one that stands about 2 m tall.  All of the folks at the session were just great people, and they did not hesitate to tackle the larger projects.  Before long the big arch was standing.

The other group was hard at work starting on the bigger, and as of yet untested, mega-arch!  As all the folks worked together, one could quickly see that this was an arch to be reckoned with!

With all the segments assembled, we started working on getting the entire arch together.  Remember, the segments are not glued together (OK, we glued a couple of the lower ones 'cause time was limited and the cardboard was slick).  The arch stands by distributing the load across its entire structure. 

Standing on tables and reaching as high as we could, however, was just a little bit intimidating.  But these folks were a great crew and everybody helped ease the pieces into place until the arch stood on its own.

Fairly confident in what we had accomplished, we all scurried beneath the arch to get pictures taken "before it fell over."  What we found out was that after the pictures were done and we were cleaning up all the materials from the presentation, the arch just kept standing there with no intention of falling over.  We could have moved that one leg of the arch toward the center just about 25 cm more to get the real graceful look of the arch, but it has to be admitted that these folks had done a marvelous job assembling four arches in one brief session.  It was now Saturday evening and so we just didn't have lots of "fine tuning" time available.  But look at that arch! And look at the smiling faces beneath it.  Thanks so much to all who attended the presentation (including Mary Jo and W.A. who were instrumental in getting the last few pieces of cardboard that we needed).  Let us know what you think of our project!

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