Q10: We are building a machine with 20 steps. Do they all have to lead to accomplishing the task? A10: As you know from the rules and the scoring sheet a machine that has 20 steps (and 5 energy conversions) is the minimum requirement for the scoring. In keeping with the "contraptions" that Mr. Goldberg drew in his cartoons we expect that, at least, 20 steps should be used to accomplish the task as stated in the competition. It is, of course, possible to have some of these steps running in parallel but those parallel steps should all be contributing to accomplishing the task. As you also know the score sheet allows for awarding points for "more than 20 steps" and the competition encourages a design theme for the machine. So if you have "more than 20 steps" it is possible to have some or all of those additional steps perform actions which add to the theme of the machine but do not actually contribute to accomplishing the stated task. Q9: Suppose we start with a container larger that 70 cubic inches, can we fill the container with some material so that only 70 cubic inches of space remains? (See also Q5.) A9: Yes, but it depends on what the fill material is and how you then calculate the remaining volume. Suppose you use dry sand as the fill material. It is densily packed (with no free space compared to the size and volume of PPBs) and as PPBs hit its top surface it will not deform to any significant degree, so sand would be an acceptable filler material. Suppose you use cotton batting as the filler material and suppose you have the upper surface at the same level the sand would have had had it been used. Between the fibers of the cotton batting is a lot of free space and the weight of the PPBs is likely to deform the upper surface of the batting and thus the PPBs will occupy that free space that had not been included in the 70 cubic inch calculation. For this deformation reason the cotton batting would not be a good filler material. Suppose you use styroform "packing peanuts" as the fill material and suppose you have the upper surface at the same level the sand would have had had it been used. Because the "packing peanuts" are large (in the same order of size as the PPBs) and because they are irregular in shape they have a "packing issue." They leave spaces between them that has not been counted as free space in the container but which, by movement of the "packing peanuts" during collisions with the PPBs, may actually become available as space during the process of adding the 12 PPBs. Of course, if your calculation on available volume takes into account the free space in the cotton batting or the free space between the styroform "packing peanuts" then those too could be used as fill material. Q8: What is the specific size of the Ping Pong balls? 38 mms or 40 mms? A8: That's a good question. On the web we found that in 2000, the diameter of the ITTF approved ping pong ball was increased to 40mm from 38mm. So we assumed that anything you'd buy now would be 40mm but if you have 38mm ping pong balls they are acceptable. Q7: Are the ping pong balls provided or do we bring our own? A7: We are not supplying the ping pong balls. Q6: Do all twelve balls need to fit in the container at the same time? A6: If you can do it, yes! The challenge is to get (and keep) as many in there as possible. If one goes in and comes out again it is not counted. Those that remain at the time of a machine reset are the ones that are counted. Q5: What type of container may be used? (See also Q9.) A5: The one specified characteristic of the container is the 70 cubic inch volume. Your team must be able to show how the 70 cubic inch volume is calculated. The fixed volume implies that the container is not "stretchy". Q4: What counts as part of the container volume? A4: The 70 cubic inch volume is that space which you use to collect the ping pong balls. Anything not attached and outside of that space is not part of the container and does not figure into the volume calculation. Q3: Can you cover the balls in anything? A3: No, the ping pong balls must be standard, i.e. usable for Ping Pong. Q2: Can we use any type of 'guide' for the PPB after the launch? A2: The challenge states that "The launch point of the ping pong balls may be no closer than 2.0 feet away from the target container ..." We expect that while the PPB is traveling this distance that it will not be in contact with any object. After it travels those 2 feet it is free to to enter the "container" or to strike anything else before entering the "container." Q1: Will the completed machine need to match the team's "Step-by-Step" description exactly? A1: The final machine does NOT need to conform with the submitted 20 steps nor does the 20 step description figure into the final scoring. The purpose of this requirement is to keep teams on track in planning and development and to ensure that teams are thinking about the minimum requirements for steps and energy conversions and how they might develop a theme for the machine. Also during the 20 step review that we do we look for safety concerns such as the use of open flames or hazardous materials.