A while ago you had a chance to ask former Navy officer, professor, and famed ocean explorer Robert Ballard about shipwrecks, his work with the Ocean Exploration Trust, his learning programs, and what he's found on his expeditions. Below you'll find his answers to your questions.

You may have read a few weeks ago about the new materials that MakerBot has introduced for its 3-D printers; earlier this month, I got a chance to see some of them in person, and have them explained by MakerBot VP of Product Anthony Moschella in a cramped demo closet — please excuse the lighting — at the company's booth at CES. Moschella had some things to say about materials, timelines, and what MakerBot is doing to try to salvage its open-source cred, despite being a very willing part of a corporate conspiracy to sell boxes of Martha Stewart-branded extruder filament — as well as a few unremarkable things that the company's ever-vigilant PR overseer decreed Moschella couldn't answer on the record for reasons like agreements between MakerBot parent Stratasys and their suppliers. The good news for owners of recent MakerBot models: they'll be upgradeable to use the new and interesting materials with a part swap, rather than a whole-machine swap (it takes a "smart extruder" rather than the current, dumber one). And the pretty good news for fans of open source, besides that the current generation of MakerBots are all Linux-based computers themselves, is that MakerBot's open API provides a broad path for 3-D makers to interact with the printers. (The bad news is that there's no move afoot to return the machines' guts to open source hardware, like the early generations of MakerBots, but STL files at least don't care whether you ship them to an FSF-approved printer to be made manifest.)

Today, the conclusion of my talk with Jim Blasko (here's part 1), who encourages you to go start your own crypto currency, because it's a fun exercise and because every entrant adds new ideas to the mix. As you'd expect, he's bullish about both his own Unbreakable Coin and cryptocurrencies more generally; how any given given currency performs, though, is an open question: U.S. dollars, Euros, or Yen may not go experience any meteoric rises, but their stability, even with inflation, is a nice feature, and so is their worldwide convertibility.

Regulation, speculation, fraud, and cultural fashions all play a role in making new currencies risky; reader mbkennel yesterday asked an insightful question: "Are you up to loaning bitcoin or something less popular for 10 years?" Confidence in any given currency can be tested with the terms current holders are willing to accept to make loans payable in that same currency. (On the other hand, if large companies will accept it in payment, they've probably got an idea that a given currency will be around next month or next year.) If you've bought any form of crypto currency, what's been your experience, and what do you expect in 10 years? (Alternate Video Link)

samzenpus (5) writes "Alexander Stepanov is an award winning programmer who designed the C++ Standard Template Library. Daniel E. Rose is a programmer, research scientist, and is the Chief Scientist for Search at A9.com. In addition to working together, the duo have recently written a new book titled, From Mathematics to Generic Programming. Earlier this month you had a chance to ask the pair about their book, their work, or programming in general. Below you'll find the answers to those questions."

An anonymous reader writes "Alexander Stepanov studied mathematics at Moscow State University and has been programming since 1972. His work on foundations of programming has been supported by GE, Brooklyn Polytechnic, AT&T, HP, SGI, and, since 2002, Adobe. In 1995 he received the Dr. Dobb's Journal Excellence in Programming Award for the design of the C++ Standard Template Library. Currently, he is the Senior Principal Engineer at A9.com. Daniel E. Rose is a programmer and research scientist who has held management positions at Apple, AltaVista, Xigo, Yahoo, and is the Chief Scientist for Search at A9.com. His research focuses on all aspects of search technology, ranging from low-level algorithms for index compression to human-computer interaction issues in web search. Rose led the team at Apple that created desktop search for the Macintosh. In addition to working together, the pair have recently written a book, From Mathematics to Generic Programming. Alexander and Daniel have agreed to answer any questions you may have about their book, their work, or programming in general. As usual, ask as many as you'd like, but please, one per post."

Their website says, 'Come for the code, stay for the people! We have awesome attendees and electrifying parties. Check out the robotics club, the automated home brewing system running on Linux, or the game room for extra conference fun.' This is an all-volunteer conference, and for a change the volunteers who run it are getting things together far in advance instead of having sessions that don't get scheduled until a few days before the conference, which has happened more than once with LFNW.

So if you have an idea for a session, this is the time to start thinking about it. Sponsors are also welcome -- and since LFNW sponsorships regularly sell out, it's not to soon to start thinking about becoming a sponsor -- and if you are part of a non-profit group or FOSS project, LFNW offers free exhibit space because this is a conference that exists for the community, not to make money for a corporate owner. But don't delay. As you can imagine, those free exhibit spots tend to fill up early. (Alternate Video Link)

samzenpus (5) writes "Jonty Hurwitz is an artist with a degree in engineering who says each one of his pieces is "a study on the physics of how we perceive space and is the stroke of over 1 billion calculations and algorithms." Recently, his nano sculpture project drew a lot of attention. With help from the Weizmann Institute of Science and using a 3D printing technique by the Institute of Microstructure Technology at the Karlsruhe Institute of Technology, Hurwitz created a number of sculptures that were so small they could fit in the eye of a needle, or on a human hair. Jonty has agreed to answer any questions you have big or very small. As usual, ask as many as you'd like, but please, one per post."

With the holidays coming up, Bennett Haselton has updated his geek-oriented gift guide for 2014. He says: Some of my favorite gifts to give are still the ones that were listed in several different previously written posts, while a few new cool gift ideas emerged in 2014. Here are all my current best recommendations, listed in one place. Read on for the list, or to share any suggestions of your own.

Bennett Haselton writes The corruption of the #Ferguson and #Gamergate hashtags demonstrates how vulnerable the hashtag system is to being swamped by an "angry mob". An alternative algorithm could be created that would allow users to post tweets and browse the ones that had been rated "thoughtful" by other users participating in the same discussion. This would still allow anyone to contribute, even average users lacking a large follower base, while keeping the most stupid and offensive tweets out of most people's feeds. Keep reading to see what Bennett has to say.

Back in November you had a chance to ask Rachel Sussman about photography and her work. Her most famous project may be the Oldest Living Things in the World, a collection of organisms that are 2,000 years old and older from around the world. Below you'll find her answers to your questions.

You can spend less than $500 if you like. That's the maximum amount allowed if you're competing in the Power Racing Series. Interviewee Josh Lee is a member of the Southern Polytechnic State University Electric Vehicle Team. The modified electric 'ride on' toy they showed off and raced at Maker Faire Atlanta (where this video was made) is just one of their many projects. And, obviously, they're just one of many 'slightly deranged' teams involved in learning about and building electric vehicles. (Alternate Video Link)

A few weeks ago, you had a chance to ask Malcolm Gladwell about his writing and social science research. Below you'll find his answers to your questions.

EVChallenge is a high school student project that converts gas cars to electric. This isn't a "someday" thing. It's already happening, and Ben has worked hard to make it so in N. Carolina. There are other people around the world doing EVChallenge, and Ben does a number of things besides EVChallenge. His Kickstarter project, for instance, was called Help Bring Back Quality Science Kits (STEM Education). It closed on October 17 after 119 backers came through with $6523, which was a lot more than Ben's modest $3500 goal. This takes us to Ben's EVChallenge simulator itself, which is a simple "breadboard" simulation of the circuitry that drives an electric car so students can learn EV (electric vehicle) principles before they work on the real thing.

This is all part of the Harris Educational effort to make science teaching fun and interesting, not just with electric cars and simulations of their circuitry, but with other kits and even training services. As Ben's Training Services page says, "Harris Educational can provide face-to-face or online training for individuals, small groups, or companies. We can also help you design and implement your own training programs." So besides the video interview here, please look at Ben's pages, this article about his work, and check some of the videos on his assorted pages. It's good stuff, especially if you have (or plan to have) kids in high school. (Alternate Video Link)

Recently, you had a chance to ask child prodigy, author and activist, Adora Svitak, about education and women In STEM and politics. Below you'll find her answers to your questions.

A few days ago you had a chance to ask the people at Hampton Creek about about their products and the science of food. Below you'll find the answers to your questions from a number of Hampton Creek employees.

A bit of housing insulation material, a battery, a motor and propellor, a radio receiver and transmitter, and servos to control the motor and a pair of ailerons, and you're ready to fly the Brooklyn Aerodrome way. This isn't a tiny radio-controlled paper airplane, but a big bruiser with a 1:1 power to weight ratio (which means it can climb like a bat out of hell) and enough guts to fly in reasonably windy conditions while carrying a camera -- except we'd better not mention cameras, since Brooklyn Aerodrome creations, whether kits or plans, are obviously intended tohelp you build model airplanes, not drones. Timothy ran into project proponent Breck Baldwin at a maker faire near Atlanta, surrounded by a squadron of junior pilots who may someday become astronauts on the Moon - Mars run -- or at least delivery drone controllers for Amazon. (Alternate Video Link)

Bennett Haselton writes A judge rules that a county has to turn over the IP addresses that were used to access a county mayor's Dropbox account, stating that there is no valid security-related reason why the IP addresses should be exempt from a public records request. I think the judge's conclusion about IP addresses was right, but the reasoning was flawed; here is a technically more correct argument that would have led to the same answer. Keep Reading to see what Bennett has to say about the case.

Dan Mcculley, the interviewee in this video, works for Intel and claims they have "about 140" projects going on inside their fabs and factories, of which the Smart Toolbox is but one, and it's one some technicians came up with because Intel workers lose something like $35,000 worth of tools every year. This project is based on the same Galileo boards Intel has used to support some high-altitude balloon launches -- except this is an extremely simple, practical application. Open source? You bet! And Dan says the sensors and other parts are all off-the-shelf items anyone can buy. (Alternate Video Link)

samzenpus writes Hampton Creek is a food technology company that makes food healthier by utilizing a specially made egg substitute in food products. The company was selected by Bill Gates to be featured on his website in a story called, The Future of Food, and has raised $30 million in funding. Hampton Creek's latest product is called, Just Cookies, which is an eggless chocolate chip cookie dough, but it is their eggless mayo that has been in the news lately. Unilever, which manufactures Hellmann's and Best Foods mayonnaise, is suing Hampton Creek claiming that the name Just Mayo is misleading to consumers. Named one of Entrepreneur Magazine's 100 Brilliant Companies and one of CNBC's Top 50 Disruptors, Hampton Creek has picked up some impressive talent including the former lead data scientist at Google Maps, Dan Zigmond. With Thanksgiving just around the corner, Dan and the Hampton Creek team have agreed to answer any questions you may have. As usual, ask as many as you'd like, but please, one per post.

Yesterday we ran video #1 of 2 about the Critical Materials Institute (CMI) at the Iowa State Ames Laboratory in Ames, Iowa. They have partners from other national laboratories, universities, and industry, too. Obviously there is more than enough information on this subject that Dr. King can easily fill two 15-minute videos, not to mention so many Google links that instead of trying to list all of them, we're giving you one link to Google using the search term "rare earths." Yes, we know Rare Earth would be a great name for a rock band. But the mineral rare earths are important in the manufacture of items ranging from strong magnets to touch screens and rechargeable batteries, so please watch the video(s) or at least read the transcript(s). (Alternate Video Link)