Epilogue: An Explanation

Forces

Hello bloggers of the internet! Welcome to the epilogue of our bridge project's blog! You thought the blog was over? Well then this is a good surprise, isn't it?! Today I will be explaining the basic physics, more specifically the forces, behind this bridge and how it was SO STRONG. Starting off, let me simply give a brief and simple definition of forces. A force is an action that causes an object to move, and when all the forces on an object are equal, that is called equilibrium, or at rest. First, let's start off explaining the forces at one of the triangle gussets, specifically, the one on the left(although both will have the same forces acting on them). 

 The area we will now focus on.

First, let me show a picture of all forces acting on this part of the triangle.

OK! With this force diagram, let me explain every force shown. To start it off, we can begin with Fn. This is called the Normal Force. Basically, this is the force acting on an object from the surface it's resting on so that gravity doesn't PULL IT STRAIGHT INTO THE CENTER OF THE EARTH AND DESTROY ITS VERY SOUL. This force is equal with gravity most of the time when an object is resting on a surface. Now, let's move on to the force labeled Fc. This is called the Compression Force. When we added the weight to the bridge to test it, the tubes of the bridge compressed making them smaller in length, although a very minuscule amount. When these tubes are compressed, they actually have a force acting on the surface to keep the bridge from collapsing down, thus making the force in the tubes stronger to sustain the bridge. Finally, I shall explain the Ft force. After the weight was added to the bridge, the thin strips we constructed were stretched which caused them to create a stronger force that was equal to the compression force so that the bridge will stay in equilibrium. Without the tension, the bridge would collapse into itself, and without the compression, the bridge would fall to it's timely demise. With all these forces equal, we achieve equilibrium in the gusset. Now, let's move onto the next gusset, the bottom center gusset.

The next gusset I will be explaining.

Like the previous gusset, I will give you a force diagram to help you visualize it.

OK! Let me start to explain the forces here now. The Fa is the applied force, and in this instance it is the bucket we applied to the bridge. The force of this object will be equal to the tension force of the strips above it. The bridge eventually broke because the force of the bucket was too big for the tension force to handle. Also note the tension forces that are horizontal. These forces must also be equal and with all of these forces equal, the gusset is at equilibrium.

Now I know what you're thinking. There is still one last gusset to go over. I have already explained all the forces on this bridge with diagrams, so there is no need for one here. To get a picture of it, go and look at the picture two pictures above. Basically, this has 3 forces, the tension force from the strip below and the compression forces from each of the tubes. These forces once again balance out to create equilibrium within the gusset.

Summary and Finale

Well, there you have it! In this entry, we covered exactly why this bridge was able to hold so much and what "magical forces" we causing it to stay in place. Once again, I would like to thank everyone for taking the time to read my partner and I's blog. You stay classy science and blog lovers!

Day 5: The Truss' Test

Explanation

Hello bloggers of the internet! Although we have finished constructing our mighty Truss bridge, there is one more feat we must accomplish before we can finally lay this project to rest. This feat is a test of the strength and support of our bridge. To test this, we will be placing a small wooden block on top of the bottom middle tube with a string attached that has loops at the ends. Then, we will be placing one end of a two hooked bar into the two holes on the strings and attach the other hook to a bucket that comes out to be about 1 kg.

 The complete setup.

Pouring the Sands of Time

Now with this setup, we will begin pouring in a cup of sand at a time until the bridge actually collapses into itself and CRUMBLES INTO LITTLE TINY PIECES. That won't actually happen unfortunately, but the bridge will either break at the strips, or will tear off one of the edges glued to the gusset. 

CAREFULLY pouring the sand.

My partner Aakash vigorously poured the sand, with each cup came a mini heart attack, until finally, the inevitable happened. Our bridge collapsed. All those hours of building this beautiful contraption were now gone in an instant.

Notice the bridge broke at the bottom middle tube. Our strips did not break, but the glue did give way and cause the tube to fall off.

Measurements and Calculations

After the collapse, our teacher took the sand that was in the bucket and weighed it. Including the bucket and devices used to hold the bucket, the total weight that our bridge held was 2,786 g. Before we actually poured in the sand, we did measure our bridge by itself, which came out to be 18.4 g. Both these numbers are helpful, since we will now be calculating the efficiency of our bridge. We take the weight that the bridge held, 2,786 g, and then divided by the actual weight of the bridge by itself, 18.4 g. The efficiency of our bridge came out to be 151.14. 

The ACTUAL End

Now with the test completed, this will mark the true end to the project and also to this blog. Thank you everyone for taking the time to read this blog, and remember to always CAREFULLY measure everything, don't just measure it.

Day 4: The End of the Beginning

It's a Beautiful Day

Hello bloggers of the internet! Welcome back to more building of the Truss Bridge. As the title of this section implies, today was, not only beautiful, but magnificent! Today marked the end of our perilous bridge building as we took both of the sides of bridge and merged them together into one huge unifying bridge structure! To get a better picture of what it is supposed to look like, take a peek down below!

The End is Nigh

Before we started to combine the bridges we needed a few more materials to combine both bridges. We were told that we were to need four 10 cm tubes. Scavenging through the rubble of our manila folder, to our despair we were not able to find a tube piece leftover that was a suitable length. But this will not take us down! For we used the strategy stated earlier and made two more 30 cm tubes. With these new tubes, we measured each down into 3 10 cm tubes. After that, we measured 5 mm from the edge of each and then cut on the corners. They turned out looking like the two below!

Using the diagram shown above, we were able to deduce how and where to put on the tubes. With a steady grip on the glue, we glued the very first tube onto a corner triangle gusset by placing the glue on the flaps and then placing on flap on the edge and the other three on the gusset. 

We continued the same process for the other corner's gusset. To glue on the gusset in the bottom center, we simply placed all four flaps on the area of the gusset. Finally, to get the top tube glued on, we placed the tube in a diamond shape on the gusset with two flaps on the edge and the other two on the area of the gusset. Taking the second side, we glued all four on at once using the same method for each corresponding gusset and tube.

Top view of both sides combined.

 Side view of both sides combined.

Now, you may be asking yourself, have they done it? Have they finally reached the end of this treacherous journey?! Sadly, no. There is still one more hill to climb before the end is reached. But this hill is small, so it won't be a difficult trek. Using the leftover pieces from the 4 mm strips, we created a cross shape on the bridge on the side by gluing each end onto the bridge. This will help give the bridge more stability and strength.

The crosses on one side of the bridge.

Using the same method, we also completed the second side with the cross.

The. End.

And now, my friends, is when we can finally take our sigh of relief. The journey is over. We've reached the end of the road. The only thing standing between us now is the test of our bridge's might and strength. But as for the bridge building, we have done it! With our trusty building supplies and wits, we were able to take a manila folder and turn it into a powerful bridge that can hopefully hold 5 kg of mass! Tomorrow we will post the results, but as for now, this is goodbye. Stay tuned tomorrow for the results! You know you want to... 

The completed bridge.

Day 3: The Truss' Trust

The Explanation

Hello bloggers of the internet! Welcome back to the building of the Truss bridge. Today in physics we performed, with elegance, the most grueling task of the bridge... the sides! What? You say this task may be a simple one? Oh, I'm afraid not my friend. This task was THE hardest part of building our bridge. Now if you want to know what the side looks like, I will once again be referring to the picture I have used multiple times to explain the bridge to all of you. Take a look!

In the simplest terms, what you see is what you get! Basically, we will be building the picture on the paper. My partner and I will be combing each and every piece of the bridge we have made and combine them into one super being!!! Or just a side of a bridge... whichever you prefer. The Truss part of Truss bridge refers to the style of bridge that was built on the sides.

MUCH More Processing

To begin this long and strenuous task, we first started to pin down the paper above with a plastic coating on top(to ensure the glue doesn't get on the paper) then pinned that down to a foam board. It should come out looking like below!

You should be able to see the four pins in each corner of the paper. Now, with that done, we will be taking one of each gusset, placing them down on the corresponding parts of the paper and the pinning them down! This process, at the end, should look a little something like below!

OK. So, now we have our basic building blocks down. Now is when we start to really go insane! Taking some wood glue, we put a very thin line on the bottom of each of the gussets A, B, and C. We took one of our 2 mm strips and CAREFULLY placed it on the bottom of these gussets. We made sure to keep the strip nice and taut for MAXIMUM STRENGTH. To help visualize this, take a peek below! If you dare...

OK! Step 1 down! We are now some unknown fraction away from completing one of the two sides! Woo! Anyway, as we traverse on the path to bridge building salvation, our next step to be taken is a huge one. We took one of our 4 mm thick strips and place against the outline on the paper. We noticed that it is bigger than the actual size needed for the bridge. This is an easy fix, as all we did was place one end of the strip at the bottom, and then marked a point about halfway through the  square shaped gusset. Then, with our trusty scissors, we CAREFULLY cut the strip at the mark. Now, with our newfound cut strip, glue it to the gussets along the outlined paths. Unfortunately, I do not have a picture of this step, so PLEASE, do not falter and press forward!

OK! Step 2 down! Now, with the four tubes we so CAREFULLY cut out of the manila folder, our next step is to lay them down on the outlines of the tubes on the paper, make lines where the tubes are angled, and cut along those lines. Then, with the new tubes, glue them on individually to the gussets. When the first is down, glue down the second. Take a peek below if this was hard to visualize!

On the left is the tube, cut down to fit into the outline on the paper, also notice the strip down the middle that was mentioned earlier, that is what the strip should look like the completed except without the custom tube.

Here is the side, now with both tubes glued and in place.

OK! Steps 3 and 4 down! The next step is one we took a breather on. Isn't that a relief? Anyway, we took one of the extra parts from the cut tube and put it down and in the center of the bottom middle gusset. We put the bottom edge on the bottom of the gusset and then marked where the top of the gusset cuts off. With our new mark acquired, we took our trusty scissors and CAREFULLY cut the tube at the mark. Now, we just laid down some glue and glue it onto the gusset. In the end, the tube should look a little bit like the picture below!

OK! Step 5 down! We are getting very close to the end, so hold on tight! Now we move to the most difficult and excruciating part of this bridge...adding on the strips and gussets to the top. This step may seem confusing, but bear with me here. First, we took some glue and put it on the very bottom of each of the tubes and glue a strip of 2 mm thickness on the bottom. Then, take a 4 mm thickness and use the same process stated earlier to cut it down to size to fit in the vertical outline on the paper. We then glued that to the top of the diagonal tubes and all through the bottom middle tube. Finishing this task should look like below!

Ignore the glue on the gusset, we will get to that in a second. Once again, we kept a steady and taut force on the strip to ensure MAXIMUM STRENGTH.

The next part of this step is pretty simple. We took a pre-cut gusset looking like an equilateral triangle(or the gusset in the bottom middle) and glued it to the top, like so!

We continued this process for the other gussets, matching each up with the correct spot on the Truss. Once we finished this, one of the major parts on our journey had been completed! This marks the end of building one side of the Truss bridge! It should look a little like below!

Repeating this process, we built the second side!

Both finished sides of the bridge.

The Continuing Journey

Tomorrow in class, we will be wrapping up this beast. We will be putting together both sides of the bridge to construct our final product! Stay tuned for more! You know you want to...

Day 2: The Continued Preparation

Introduction

Hello bloggers of the internet! Welcome back to the building of the Truss bridge. On our second day, we continued to build more parts necessary for the bridge. Today we will be making tubes that are 30 cm long and have 10 mm sides. Then we will be also making gussets which are parts that connect the bridge. To get a better understanding of them, look at the picture below! 

The spots labeled A, B, C, and D on the are the gussets. The job that they do is hold together the beams that make up the support for the bridge. We will be needing four of each gusset.

More Processing

Continuing the process of building more parts for the bridge, we started using more CAREFUL measurements to cut out each individual tube. We will be needing four sides of 10 mm width and one side of 6 mm width. The 6 mm width will be handy later. We marked the first four spots at 10 mm and then the fifth at 6 mm so that we can easily bend the paper at the lines while following the marks. After finishing the marks, we CAREFULLY cut out the piece by cutting at the line marked at 6 mm (or 46 if you add in the 4 10 mm marks). Then, we took the 6 mm edge, folded it under the opposite 10 mm side and glued it together. We continued this process for the next three tubes and they came out to look like the picture below!

The four tubes, each with 30 cm length and 10 mm width.

Now with these four tubes cut, glued, and completed, we heartily moved on to the gussets! Using the paper of the bridge above, we traced each individual gusset onto the manila folder and then CAREFULLY cut out each piece. After a long and tedious task, we received our final product which can be seen in the picture below!

Four of each gusset as shown above.

Moving Forward

Our next day in class we will be constructing each side of the bridge by combing all of the parts that we toiled to measure and cut to make the sides. Stay tuned for more! You know you want to.

Day 1: The Preparation

The Project

Hello bloggers of the internet! I am here to explain in detail the building of a Truss Bridge in my Physics class.  In case you don't know what a Truss Bridge looks like, take a peek below!

Of course, we don't have the time, money, or supplies to build a bridge of that style or magnitude... So! We will be building one that looks like the picture below with paper strips cut out of manila folders. 

This bridge will be consisting of four different types of materials. Those materials are: 4 tubes of 30 cm in length with 10 mm sides, 5 strips of 30 cm length by 2 mm width, 4 strips of 30 cm in length with 4 mm width, and 16 gussets that hold the bridge together. The gussets are made of normal printing paper and can be seen on the diagram above on spots A,B,C, and D.

The Process

On our first day of vigorous work, we used our trusty ruler to get near precise measurements on the 2 mm width from the manila folder. The manila folder was already 30 cm so we did not have to measure for the length. With our measurements, we made small marks on each side of the folder to CAREFULLY cut out the strips with an exacto knife. We continued this process and acquired the five strips with 2 mm width. We repeated the same process to get the four strips with 4 mm width. 

CAREFUL measurements.

Finished Strips

At the end of class we were able to finish measuring and cutting out the strips and they came out looking like below.

The 4 mm thick are on the left and the 2 mm thick on the right.