Projects+Questions

__//**Motion (Projectile) Project 2014-15**//__


 * __Reminders:__**
 * 1) The projectile AND launcher must EACH be made of at least three of the materials form the list. If you are not sure of the acceptability of a material, bring a sample to show me. One material detail distinction that I made is that hot glue can be used ONLY on the launcher and NOT on the projectile.
 * 2) The launcher must be rubber band powered, but rubber bands are not any other part of the project other than the power source.
 * 3) There will be approximately 4 ft of length between the firing line and the cabinets, so that is the limit for length of the launcher.
 * 4) As stated in the notes, which are posted on the wiki, the key to success on this project is "control and consistency". You want your projectile to do what it is supposed to do every time it is fired, so you have to focus on controlling things like the tension on the rubber band. As a rubber band gets used, it tends to stretch out and that changes the tension on it and how much force it will apply to the projectile. Once a rubber band is used a while it doesn't stretch out a whole lot more so it will tend to stay rather consistent. If that rubber band breaks and you put a new one on, it should be the same size and type of the previous one, but it will also still be "fresher" an not as stretched out. Therefore, the tension of the new rubber band that is the same size and type as the old one will be different than the one it replaced because it will not be stretched out. It is wise to pre-stretch several rubber bands the same so you have new ones ready to replace broken ones without changing the performance of your project. That is one example of how controlling something that most people might not even think about can be a very important factor in the success of a project.

A: There is no set size or restriction on how big the projectile can be. The nature and physics of the task and the design of the launcher will will naturally influence the size and weight of the projectile, but remember that there is a minimum of 1 inch in any dimension. A: No. The projectile must be free-flying. Also, any attached string would ultimately touch the bar and that disqualifies that shot. A: The projectile will be marked where it first hits the floor. Bouncing/rolling/sliding will not count in any way.
 * __Projectile Questions__**
 * Q: How big can the projectile be?**
 * Q: Can a string be tied to the projectile to stop it at a certain point?**
 * ** __NOTE__: ** ** STRING IS AN APPROVED MATERIAL AND CAN USED USED, BUT IT CANNOT BE USED TO KEEP THE PROJECTILE ATTACHED TO THE LAUNCHER, NOR CAN IT DRAG ON THE BAR TO ALTER THE PROJECTILE'S TRAJECTORY. **
 * Q: Where will the projectile landing be marked?**

__**Launcher Questions**__ A: It cannot be higher than 2 ft from the floor. There will be approximately 4 ft of length between the firing line and the cabinets. A: There are no restrictions on the number or size of the rubber bands. Remember that the rubber bands are only used as the power source and not used as a building material in any other way. A: The launcher can be kept from sliding backward during launching by using your feet or a hand, BUT you CANNOT support the launcher or aid in aiming it by hand. It must be free-standing and self-supporting.
 * Q: How big can the launcher be?**
 * Q: How many rubber bands can the launcher have?**
 * Q: Can I hold onto the launcher with my hand?**

__Materials__ Q: What kind of tape can be used? Q: What kind of glue can be used?** A: Elmer's (or other typical school glue or craft glue), super glue, rubber cement, Gorilla Glue, and hot glue, BUT hot glue can be used only on the launcher and NOT on the projectile. Also, you cannot use construction grade adhesives such as PL200 that is used to fasten plywood to a house frame. "Stick" to common household glues and adhesives. (Pun intended) A: If the yarn is fairly thin and string-like, it can be used. Thick, heavy yarn that is rope-like cannot be used. Again, if not sure, bring it in to show me. A: Yes/ If they are marketed as craft sticks, then you can use them. This includes the wider ones, thinner ones, etc. You are also allowed to cut them. split them or modify them as needed. A: Yes. The rubber bands can be manipulated as needed, as long as they are only used as the power source and not as a structural building material.
 * A: Scotch, masking, electrical, duct tape are all acceptable, EXCEPT for metallic duct tape. There is a type of duct tape is is actually very thin metal. That cannot be used.**
 * REMEMBER - HOT GLUE CAN BE USED ON THE LAUNCHER, BUT NOT ON THE PROJECTILE
 * Q: Can yarn be used as "string"?**
 * Q: Can the craft sticks be the ones that are bigger than the typical Popsicle sticks?**
 * Q: Can the rubber bands be cut and used as a single strand?**