i have this extra credit project in my engineering graphics class, i have to keep a glass marble moving for the longest amount of time. the things that we are alowed to use are: - 2 paper cups - 2 medium rubber bands, - 1 small rubber band - 3 sheets of printer paper - 1 large manila onvelope - 20 toothpicks - 6 drinking straws - 6 large paper clips, - 10.5 feet of twine - one roll of 1/2 inch masking tape - and one 22.5 x 17.25 inch sheet of non-curegated cardboard my idea is to make it move verry slowly, but every way i can think of has a major flaw, can i get some help.
Can you interact with the system after you start it up? Meaning could you just blow around the marble? Or do you need to rig something up that will start it moving without you touching the marble at all and then keep it moving for as long as possible?
ooooo ive done somthing similiar to this. no you cant touch the marble at all. basically what you want to do is do very small slopes otherwise the marble will speed up too fast. i would use the paper and toothpicks to where they hit the marble and slow it down a bit
Do you have to use everything? And buddy, you have masking tape. ur set. Make a tube with the manila envelope and the cups at the ends, fastening with the tape, and use the 2 rubber bands, fastened at each end, so when the marble rolls to one end, the weight pulls the band down,the band pulls back, the marble rolls the other way... repeat. Mount the tube on a tower made of the cardboard fastened together with the tape, and hang the string in a small loop that the 2 rubber bands are held in. make sure it is sturdy by supporting the tower (a small tower now, less than 30cm tall) with the toothpicks stuck into it to support and the cardboard doubled back over itself where needed most. The straws... I dunno, tape them on the outside if u really need to include everything... Remember that the tube has to be as long and skinny as possible, the tower has to be short but tall enough so the tube can swing sufficiently, and sturdy enough to hold the rubber bands. Use the 2 medium rubber bands for the sides, and use the small rubber band to attach to the middle of the tube for maximum support. The tube needs to be as strong as possible, so reinforce it wit whatever you can, and the rubber bands need to be stretchy, so if they arent stretch them for a while. Btw, I don't take engineering, I'm in 9th grade, and I really am just designing off the top of my head. Evaluate and see if this will work, I'm confident it will, but hey - I'm not the one taking engineering classes. BTW good look in your engineering classes. I am probably going to get into some sort of financial learning, but I may minor in engineering, before I (hopefully, I dunno how to pay for it), get an MBA. I like the subject a lot - in fact I am looking into taking night classes about it (I know I'm a geek shut up). Wow long rant for me. I'm done now.
i was thinking of somethin simalr to the tube, my plan was to ues the cupes and string to build a pully system so that whenever a cup gets to the tow more weight is added, the marble would be the first weight dropped, then it would go up and down, oh i frogot to mention i cam tape it to a pole from the flor to the celing and to desks in my clas to give it height. i was also thinking of cuting the cardboard up so that it was a zig-zag cours on a slow incline. one last thing i have a choice of marble size, 1 inch or 1/2 inch diamiter,i think i will be using the small due to less mass.
Make a crude trebuchet, will move for a long distance, all the the materials seem to be perfect, google it for plans. 'doc
I'm in the final year of an engineering degree, so I couldn't help myself The first possibility is to use the elastic bands to store energy. As far as I can see, they can store a lot more energy than the gravitational potential of letting the marble role down a gentle incline (unless you had a lot more cardboard). The other problem with the rolling marble is that there is to much rolling resistance; You only have the initial energy input, so to make it move for as long as possible, you want minimum energy losses for the duration of it's movement. However, the rubber band will also have hysteresis losses when it extends and contracts. You could construct a system whereby a twisted rubber band lifts a mass (including marble) suspended on the twine (over the edge of a table or something), by turning onto spindle which is turned by the rubber band. When the mass reaches the top, the rubber band is fully unwound and the mass descends, retwisting the rubber band. The cycle then repeats. Another possibility is to make a pendulum with a large mass (including the marble) on the end. The key to this one is to minimise losses as far as possible. The only real losses are air resistance of the moving mass and friction at the pivot point. The air resistance is likely to be alot larger than the friction at the pivot point. This is why you want the mass as big as possible. The larger mass means a longer periodic time and a lower average velocity for a given pendulum length; drag increases proportionally with velocity squared. Drag also increases linearly with cross sectional area so you want to minimise the size of the mass too (in the direction of travel that is). To reduce frictional losses, you could lubricate the pivot with some kind of grease. I leave construction up to you. My instinct says the pendulum is likely to be most successful due to it's simplicity. The best thing to do is to build some prototypes to see which is best.
That was my thought, but I was thinking of the suspended load spinning backwards & forwards, using energy stored in the rubber bands and twine as the initial source, and increasing the load mass by filling the cups with water (plus biggest marble). It's again simple harmonic motion, so would the changes in direction count as stops? Or set fire to all the paper, generate steam in a cup, pass through a straw, point it at one corner of the suspended envelope containing a small marble so it moves in the stream of steam. Mk II - increase the energy store by doubling the twine to two parallel strings separated by a couple of toothpicks top & bottom...
does the marble have to move, or be in motion? possible to construct a paper hampser wheel, and let the marble roll in the center? - motion with no vector.i would checkthe rules and see if this could apply, the marble would just be roatating, not moving in a linear vector like most people would assume. but motion is motion, wether in a straight line, an arc, or static roatation. i see a flywheel affair going on with the rubberbands to store and transfer energy, and a sort of cardboard and masking tape racheting gearbox. paper cups in a dual balancing rocker setup - one goes down, winds a rubber band, as rubberband releases, the other cup raises, repeats process in opposite direction, and the gearbox (like a watch movement kinda) keeps all that energy slowly spinning the hampster wheel.
If you are allowed water.Fix one cup about an 25mm above the other using cellotape and string,tie end of string to top cup and take through a pulley made of a paperclip and attach as high as possible with cellotape,attach other end of string to a basket made of the envelope and reinforced with the tape.Make tiny hole in bottom of each cup and fill with water,chuck everything you have left into the basket,including cellotape and marble and then be prepared to sit all night
longest time in motion, no water, and only one marble but i gave a choice in size also i was thinking that the pendulum would be the best idea, the string is long enought,and if i use all the weight and shape it right it might just turn out like those pendulums that tell time by the rotation of the earth, http://www.calacademy.org/products/pendulum/page5.htm i would love to see this thing move for DAYS http://www.calacademy.org/products/pendulum/page8.htm
if you have an unlimited amount of toothpicks, just make a very wide zig zag on the cardboard at a slight angle, so the marble goes in the "track" back and forth very slowly.
