Mission Possible B
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|Mission Possible B|
|Engineering & Build Event|
|Test Exchange Archive|
|There are no question marathons for this event|
|Division B Champion||Russell Independent Middle School|
|This event was not held last year in Division C|
Mission Possible B is an event in which teams make a Rube Goldberg device which uses certain tasks and runs as close as possible to the ideal time to gain the maximum number of points.
Mission Possible is all about using simple machines to create a chain reaction, using a number of tasks designated by the rules to achieve the maximum points.
This type of machine is called a Rube Goldberg device. A man named Rube Goldberg made up this type of machine, and so it was named after him. Basically, a Rube Goldberg machine implements a way to finish an often simple task in a very complicated fashion.
For example, a machine might start with the opening task, which was, most recently, using a plunger.. The hit front the plunger might knock down a domino, which might land in a pulley that pulls an object a few centimeters. The pulling of the object would hit a lever which would open a flap that would allow a ball to roll down a ramp, hitting a mousetrap that would then release a string with a weight on it, which would hit another lever and raise an object, and so on and so forth until you reach the final task, which was raising a flag in 2016. However, this example machine doesn't use all the simple machine transfers (there are a maximum of 18 storable transfers), so it is not ideal. This is a frustrating event at times, since it requires a lot of testing and tweaking.
The challenging part of this event is not building the machine, but making it reliable so it works every time. Since it is not ideal for anything to have to intervene after the reaction has started, the reaction should seamlessly work on its own every time.
There are six types of simple machines. They are:
- Inclined Plane
- Wheel and Axle
Levers are one of the most commonly used simple machines in both our daily lives and this event. There are three types of levers, called first class, second class, and third class. First class levers are the kind that you probably think of when you think of a lever- the fulcrum is in the center, and the load goes on one end and the force on the other. Some real-life examples of first class levers are pliers and a hammer (when you're using it to pry up a nail). In the pliers example, the hinge on the pliers becomes the fulcrum, and we have the load enclosed in the jaws of the pliers and the effort of your hand squeezing the handles. Next, we have the second class lever. This lever has its fulcrum on one end, with the load in the middle and the effort on the other side. Two prominent examples of this lever are wheelbarrows and nutcrackers. To go more in-depth, imagine a wheelbarrow. There's handles you hold on to, or where you provide the effort. The wheels provide a point of balance- in other words, a fulcrum. And, of course, your load, the mulch or dirt you're carrying, is in between. Finally, the third class lever is similar to the second class except that it has the effort in the middle and the load on the end. A great example would be your own arm- your elbow is the fulcrum, the load would be whatever you're holding in your hand, and the effort comes from your forearm.
Another common simple machine is the inclined plane. This simple machine uses a ramp that lessens the force needed to get something the same distance off the ground as if you were just lifting it. In the Science Olympiad rules, inclined planes must have an object pushed or pulled up them (NOT down, as this would be too easy to accomplish. Inclined planes in real life include wheelchair ramps, staircases, and slides (though that goes downwards).
Although wedges may look somewhat similar to an inclined plane in theory, in practice they work quite differently. Wedges allow you to push two objects apart more easily (or to split an object in half). When the wedge is pressed in between two objects in your machine, it should separate the two, not just push slightly and cause something to fall because of gravity. There are many real-life applications of wedges, including knives, nails, and axes, to name a few.
Sometimes less commonly used in the event, screws are a simple machine that convert rotational force to linear motion. They accomplish this task through threads with a certain pitch (in more commonly used terms, ridges with a certain angle relative to the body of the screw) that force the screw farther into its hole. The main real-world examples of screws are, well, screws, along with threaded rods (this rotational to linear motion is what allows for many braking systems in vehicle events) and the moving part of vises.
Wheel and Axle
A wheel and axle is a simple machine that consists of a wheel attached to an axle (think about cars) and transfers energy from one part to another. This part is often very challenging to get right. First of all, you cannot just roll a wheel attached to an axle down an inclined plane. That would be an example of only one force, the wheel and axle combined, in one directional force. For a wheel and axle to be legal, the forces have to oppose. A common example for this is a windlass. This involves an axle inserted into a vertical surface and a wheel put onto the axle so that it can spin, and attaching a string to the axle, so that if the wheel spins, the axle does also, pulling the string. Since the axle is staying put, opposing the force, or the wheel, and transferring energy via the string, then this would be a legal and functioning wheel and axle.
A pulley is a wheel and axle that changes the direction of a force with a mechanical advantage to transfer energy. As with a similar wheel and axle, this is a very challenging simple machine to get right. First of all, the definition of a pulley is often confusing. It cannot just be a wheel and axle with a string on one side and a weight on the other. It has to have a mechanical advantage, or a benefit of saving energy, to be considered a pulley. The mechanical advantage of a pulley is the number of parts of the string that act on the force. An example of this fitting into a Mission Possible device is sliding a piece of wood out from under a weight attached to one side of a string, using three wheels and axles and a length of string to lift another, lighter, weight that lifts up to send a ball rolling down a ramp and up an inclined plane.
While you may be tempted to fill your machine with many levers and other more common simple machines, in order to maximize points, you should try to include as many of the types of simple machines as you can. You will get points for each UNIQUE transfer (counting each class of levers separately).
Your device will need to run as close as possible to the Target Time provided by the Event Supervisors at the competition. While some devices might naturally take a long time to run, most will only take a few seconds. It is important to implement a way to adjust the time each run takes, which may not (and probably won't) be a simple machine. Often, these parts of devices include a substance such as sand or rice going through a small opening, building up and eventually becoming heavy enough to trigger the next task. However, these methods can be inconsistent, and many other ways are possible.
Another important component of this event is writing your Transfer Sequence Log, or TSL for short. This document lists all your transfers, including the start and end task, and how many points they're worth (even if they're repeats and worth nothing), as well as a brief description of each. It's worth points, so not doing it is harmful to your score!
Most recent years have included one or more tasks that the device must complete, either to start the device, during the run of the device, and/or when completing the device run. These predetermined tasks generally vary from year to year in order to ensure that teams need to address a new engineering challenge every year.
Some start tasks in recent years have been:
- Dropping a racquetball into the machine
- Operating a plunger
The starting tasks often involve putting kinetic energy in your device in ways that might be very variable depending on how you do them each time. For instance, you could accidentally pull your plunger back a different distance every time if you were not careful about it. This could create errors in your device's run. You should try to figure out a way to make your start task the same every time.
Recently, some of the ending tasks have been:
- Raising a flag
- Ringing a bell
Generally, the ending tasks involve something the judges can either hear or see- some kind of output. It is important to make sure that your task is obvious when it is completed-this is important not only for timing of your device but, in the case of the bell, actually getting the points for that task. If, for example, your bell could not be heard ringing, you wouldn't get its points.
Things to Keep in Mind While Building
- Make sure to label each task within your machine with little pieces of paper. That's a requirement!
- The simple machines of the same type do not have to be unique. Note that consecutive machines of the same type (even though unique) still only count as one machine.
- Make sure to meet the general requirements, since failure to do so is a severe penalty (you will be placed in the second tier). Make sure that all parts of the device, including the outer walls and base plate fall within the legal dimensions of the device.
- Be safe by using a mechanical timer, so that you can fall as close to the ideal time as possible. One method would be to use a long screw to eat up time. This way, you can adjust the time it might take to finish that particular task.
- You cannot use any loops or parallel paths in the device. Make sure that the action is linear from start to finish.
- The highest part of the device automatically designates the top boundary of the device.
- You can start and set parts of the device operating before the pulling of the string (such as pendulums, springs, etc.).
- You cannot touch the device after it has been started without losing points. This is why the reliability of the machine is important, so you do not have to intervene in the middle.
- Don't forget your TSL! It is required, and gives easy points.
- Remember that you will probably lose any positive points for time if your device fails to complete the task, but continues to operate.
- Try to stay within the ideal time, but if that is not possible, better have it finish than fail!
- Know your task sequence list as well as you know the rules. Be able to explain everything.
- Go with the simplest way possible. Don't over-complicate things, creating more room for failure. Also, build things with a durability factor. There is more reliability this way.
- Draw all your designs and keep them together in case something doesn't work and you need to build something new.
- Prepare for every scenario you can think of. Bring just-in-case items like tools or extra materials you need, but don't go overboard.
- Test your device prior to competition many, MANY times--do not just build it and bring it in.
- Always allow room for improvement. You don't need to have the box state-ready if you don't need it to be that good at Regionals. This will reduce the chance of failure if you keep it simple.
- Practice with your partners and make sure that they know what they're doing!
- You can use small pieces from Erector sets or Lego sets to get gears (not legal for some tasks), pulleys, and plates of metal with holes pre-drilled.
- KISS! Keep it simple, stupid. This has been mentioned many times but it can not be stressed enough. Yes, domino trains are cool. Baking soda and vinegar inflating balloons is even cooler. However, they don't count for anything except maybe time (but there are easier ways to make your device go longer), and they affect the reliability factor of your machine. Stay with safer transfers and the tasks listed in the rules.
- Double check to see if you have everything! It's bad if you realize you forgot your TSL back at your home state at Nationals!
- Devise a system in which each of the people on the event have a designated part in setting up the machine, so that you can be ready as quickly as possible.
- And last but not least, KNOW THE RULES. You can even tape them to your box if the event supervisor doesn't agree with something in your device to back yourself up.