Science Freak

hi, i was wondering if anyone knows any websites or videos which effectively cover the lesson on thermal energy, heat and temperature. for some reason i can't seem to pick things up in class so i have to go looking for lessons on my own time. thank you for your help.

basically what i mean is if you apply force in <------ and ------> direction of the bridge, the top surface is under horizontal tension, so when there is weight placed on top of it pushing down, the horizontal tension stops the straws from collapsing down and it can hold much more weight than it could without this horizontal tension. the 1 side of the bridge alone can't really hold the book up, it keeps pivoting on its anchor points so its hard to balance, so after i put the book in 2 string loops and put the loops around the bridge's frame i was able to apply that same pressure of the book upon the structure to see if it can hold, and it did. and it is a pity that only 50 straws are allowed, or else i could probably make an amazing bridge with the info from this forum

update: i just found out that michel's design, there is a lot of tension downwards on the upper part of the bridge (the part that is in contact with the traffic) so when i made my actual bridge (only made 1 side, to test how it works out) it turns out that if i pull hard on both sides, i give it some horizontal tension so when that vertical tension pushes downwards on it, rather than the straws collapsing inwards the two forces counter each other for a more firm and stiff "walk way" also, i made 2 string loops and put them on both ends of my physics book, then i put the loops onto my 1 side of the bridge (by 1 side, what i mean is, there need to be 2 sides and then more straws connecting those 2 sides and making a one complete bridge, i only have 1 of those two sides made) i tried to lift the book but it didn't work, the straw upper structure of the straws was collapsing inwards, so i pulled hard on both sides and it allowed me successfully lift the book with just 1 side (although it was really hard to balance the string on just one side) i'm taking this frame to school along with the diagram so my partner can better see what we gotta do. this is going to be great. if we get it right, i'm expecting it to hold at least 2 books if not more. thank you michel123456 for the design and thank you everyone for the input

thank you everyone for their input, and right now i have 3 questions; 1. michel123456, that bridge diagram, is it drawn to scale? if no would you think it'd be possible to get a scale diagram with lengths to ratio for optimal performance? 2. what do you guys i recommend i do about the bendy part of the straws? should i cut it out or keep it? what i fear is that when the weight is placed onto the bridge the bendy parts will give away. since the weight is gonna be a downward force its gonna put tension to the middle of the bridge and compression towards the ends branching out towards the anchor (or so i assume) 3. what do you guys recommend i make the lengths of the pipes? if i make the triangles a bit bigger (according to west point bridge designer 2007) in the "/\/\/\/\/\/\/\" design then it can hold more weight but it will require more materials but if i make it a bit smaller then it takes less material but its harder to make and can't take as much weight (its harder because we would have to put together a bridge of smaller scale, so making the individual parts of the triangle is a bit harder

lol i never realized that it was so famous (the bridge building i mean). well since all we have at our disposal are 50 bendy straws 2 x 75 minutes classroom periods (it MUST be done in class) and some masking tape, i doubt i'll be able to make any successful suspension bridge. the idea to build the " |\|\|\/|/|/|/| " design has been scratched off the list, although it is achievable, it'll be a pain to get the angles to a good enough degree for it to be successful. some of my ideas include over head arch bridge, like -----> http://reccs.uni-obuda.hu/en/index.php?q=gallery&g2_itemId=110 or a classic arch bridge ----> http://www.corbisimages.com/images/67/7896F387-F20F-45E4-9F10-D886612CBE8D/42-17311596.jpg but the problem with classic arch bridge is that it requires a good support to either the ground or the sides of the 2 anchors from below, so that'll be hard to achieve on tables but my favorite design is the one i came up with last night. its basic, its simple, it can be made easily, and it should work. it looks like this (Side view) ________________ \/\/\/\/\/\/\/\/\/\/\/\/\/ ________________ <-------- of course this line is suppose to be a bit higher up and the "\/\/\/" are 45 degrees so basically, i plan on building 2-3 pairs of those, and connecting each pair with straws (bird's eye view) "| | | | |" placed like that. the point of making multiple beams like that is its 1. quicker (i have a partner so we can both be working on a separate beam at once) and also it allows us to use minimal material to gain good strength (if i was to add any suspensions or more underhand support it would end up making the 1 bridge stronger for sure, but a lot of that potential of the straws that i'd use would be wasted). our first work period is friday 2nd is monday and then i guess its prolly due at the end of the class?back in grade 7 i took the first place prize in paper Olympics bridge building (it was just a small classroom challange) and this time i plan on winning this challenge also. lol there are a lot of fancy designs out there, and although ours is prolly not gonna look like any of that, ours is prolly gonna look like a crappy piece of art, but what i do know is, whatever its gonna look like, its gonna mean business

ok, so after watching the Mythbusters launch the "civil war era" hybrid rocket, i wanted to make a very mini model rocket that works myself. after some research it became quite apparent that although the fuel part of a hybird rocket (paraffin) is easy to find (PS idk yet if the common grade found in the market is able to sustain combustion but i will look into that a bit after solving the oxidizer issue) getting your hands on a liquid or gas oxidizer in such small quantities is quite difficult, not to mention hard to handle (hard compress oxidizers enough to hold it in liquid form). after finding about hydrogen peroxide i decided to try and see how it works. i bought some H2O2 from my pharmacy, and obviously, with it being 3% H2O2 and 97% water and stabilizer, it wasn't really going to work. so started purifying it through freezing (will get a little less than 50% H2O2 at best, since interestingly, at 50% H2O2 + 50% H2O, the mixture's freezing point drops extremely and its hard to freeze it). what i'm wondering is, how will >50% h2o2 work as an oxidizer? especially since 50% of it will be water. and also, how does H2O2 (concentrations of like 80%+ that are used for rockets) work to oxidize a fuel in general and how does it work in rockets. also, do other liquid/gas oxidizers work in the same manner? Thanks for your time

lol, i know that this is kind of silly, but our teacher has assigned us a bridge building project (its silly because we're in grade 11 ) we're going to be given 50 bendy straws and some masking tape. our goal is to create a bridge that spans (either 1 or 2 feet, i'm not completely sure but i think its gonna be 2 feet, the sheet says 2 tiles, the tiles are i think 1 foot each). its suppose to support the weight of our physics text book. the more it can handle the better it is. back in grade 7 when i did this, we had to make a bridge out of 1 Que-card to (i chose to wrap the paper into a stick diagonally as tight as possible and set the class record of a few kg or so (lol i still remember, almost all of our teacher's weight set was on my bridge before it collapsed, so i'm gonna assume somewhere from 5-10lb?)but this time, i'm not sure how i'm going to do it. there are so many choices... my current plan is to make a simple bridge with a platform and an overhead "cable" (also going to be straw) and make triangles kinda like |\|\|\|\/|/|/|/| <--- that. although it would be good to support the book's weight if it was going to be put in the middle of the 2 side structures, i think that the weight will be on the top (i don't think that there would be another way). if anyone has any suggestions as to how should i design it and what should it be like, it'd be greatly appreciated. Thank You for your time.

sorry if this has been asked before, i tried to search for it but couldn't really find anything. my question is: what is the current status behind the collapse of the wave function, what are the scientists saying? did the actual act of observation collapse it or did the method of observation collapse it. ive seen many sites talking about the dual slit experiment and how when we tried to peek which slot the electron went through it only went though one. but what i don't get is what are they implying? we collapsed the wave function through the act of observing or because of the method of observation we used? Thanks for your time.