The two big news items for STEM holiday shopping this year are a) Robots have leveled off in complexity and price and b) slime has come of age.

You can go the Mindstorms route with something like LEGO MINDSTORMS EV3 31313 Robot Kit with Remote Control for Kids, Educational STEM Toy for Programming and Learning How to Code (601 pieces), which is very expensive but also very adaptable and part of a large universe. This kit overlaps with the kits used in modern day STEM classes, and there are myriad sensors and other add-ons, also expensive, that you can get. I’m telling you about this because it is the Rolls Royce of robots, but I’m not necessarily recommending it. LEGO seems to be going in a slightly different direction these days, and while Mindstorms is not going anywhere, there is a new animatronic kid on the block.

The newer LEGO alternative robot is the LEGO Boost Creative Toolbox. When Boost first came out about a year ago, it promised to be the start of a whole new LEGO project. The project is taking off slowly, but it is taking off. For a much smaller price than you need to pay for Mindstorms products, Boost provides a programmable versatile robotic kit. The happy go lucky guy you see in this photo can be built, with materials that come with this kit and following supplied instructionws, into a cat named Frankie, a guitar, a roving exploratory vehicle device, and an “auto builder,” which is a device that makes things.

This aftermarket book by a well known LEGO designer provides detailed instructions to use the materials that come with the Boost kit to build a large number of different things, such as doors that open and close, or machines that lift or shoot things, etc. You can use these smaller projects along with our own imagination and a big pile of LEGO bricks to build … whatever.

Also, the Boost project itself, at LEGO, has started to develop ideas, with some degree of instructions, to take kids like this LEGO City Arctic Scout Truck, and build them slightly differently using parts from the Boost kit, to make what would be a normal non-electronic LEGO build into an actual programmable robot. I see a great future for Boost. I am on the verge of figuring out if it is possible to purchase LEGO Boost parts — the ones that are programmable and move tings — in order to further develop this project. One open question in my mind is how Boost software, which runs on a phone or tablet, would distinguish among multiple “hubs” (the key part that coordinates the other parts). We shall see. Anyway, Boost is great fun and very much worth a look.

At a very different part of the Robot spectrum is my favorite, and the very hard to beat in terms of price, buildability, and usability, is the Makeblock Robot Kit. You will want to click around to see what all the slightly different version are, but what you are looking for is probably the bluetooth enabled straight forward robot. There are kits you can get to make the robot walk funny, etc, but the basic robot with the wheels is what you mainly want.

Makeblock is easy to build and will take you much less time to go from zero to full Robot than any of the LEGO products mentioned above. But, as is always true with LEGO, modifying the shape and design is easier with the bircks than with the nuts and bolts used in something like the Makeblock Robot Kit. It is all a tradeoff.

Makeblock uses, as do the LEGO devices, a straight forward, scratch-like drop-the-block style programming system.

The Learning Resources Botley the Coding Robot Activity Set, Code for Kids – Toy of The Year Finalist is a softer, easier, more little kid friendly version of a Makeblock style robot.

It is sturdier than the other robots. It isn’t that the other robots break, but rather, because of the flexible design, they can more easily fall apart. A little kid, say a five or six year old, might cause havoc with a large LEGO build, or they might swallow the small parts with a Makeblock. Botley the Coding Robot is better for little kids, because it gives the basic functionality (sensors, movement, program-ability, etc.) in a device that will hold up to rougher treatment, can’t be easily swallowed, and has no sharp edges. Mostly.

You know those Rube Goldbergesque gravity driven marble kits, where you put the marbles in a thing, and maybe a battery powered screw of Archimedes or something lifts them up, then they come rolling down, etc. etc? They are fun but sometimes don’t go together quite perfectly, or there is some part that comes flying off half the time a marble hits it, that sort of thing?

There are, I think, two flaws in these toys, typically. One is that they use lighter marbles or shot, made of plastic. That is probably a great safety feature, but if they were heavier and better designed they might produce improved results. the other is that the way the parts go together is not well engineered or designed.

Well, the Ravensburger Gravitrax System, which has man expansion sets and add ons, much like the original gravity based fancy toy, Hot Wheels, is more precision designed and does not have those problems. People rave abut the Ravensburger marble toy system, and the system has gotten all the usual awards. I’m pretty sure you are going to want one of these. And several expansion sets.

The day of slime has arrived. Slime is a term referring to a range of substances that have the common property of sliminess. But there may be other properties as well. For example, there is phase-change slime. If you touch it quickly is is hard, but it will otherwise be slimy (uses corn starch). There is magnetic slime, where magnetic iron filings have been mixed into the slime. There is glow in the dark slime.

I really don’t have a specific slime kit I’d recommend, but as far as I can tell, the best to are the NATIONAL GEOGRAPHIC Mega Slime & Putty Lab – 4 Types of Amazing Slime + 4 Types of Stretchable Putty including Magnetic Putty, Fluffy Slime and Glow-in-the-Dark Putty, and another one that I don’t have a link for but you get from the Scholastic book club (you know about that if you have a kid in an American school).

Which reminds me of something else. If you don’t buy a full featured slime kit, you still have to get some form or another of Magnetic Putty. We picked up a can of Magnetic Putty at a state park gift shop last summer. I was thinking it was going to be just another dumb toy that breaks right away. Turned out to be really fun. There are a lot of different forms, look around. It is like magnetic slime but, unsurprisingly, putty like instead of slimy, and amazingly, does not easily dry out.

You could consdider geting one of the Kano Computer Kit , a way to build a $35 computer for a mere $240 bucks. Or ou can get a simple Raspberry Pi 3 Model B Motherboard, which is at the heart of the Kano, and using spare parts around the house, build a working full featured computer. Or, in between and a very good value, you can get the CanaKit Raspberry Pi 3 B+ (B Plus) Starter Kit (32 GB) or similar, which is the Raspberry Pie motherboard with additional parts you need but may not have laying around the house, such as a power supply, an SD card, etc. You will still need a keyboard, a mouse, and a random TV or monitor that takes an HDMI input, but you’ll have the fully functional computer for a good price! The Raspberry Pie operating system (a form of Linux) comes with some pretty cool kid stuff, including a Python programmable version of Minecraft, and Wolfram.

Also have a look at the Wonder Workshop Dash – Coding Robot system for younger kids. This is a classic and well tested robot kit, but I have no direct experience with it. Looks good, though.

I’ve already recommended a rock tumbler as a great STEM gift, and on a related note you might consider National Geographic Geodes , which may or may not come with safety glasses and a hammer. Be careful with this one, but it is fun.

Erector sets are classic and underrated. They have also gotten quite expensive, but also, much more elaborate and probably patience requiring then they ever were. I like the Erector Super Construction 25-in-1 Motorized Building Set and XL 2.0 Robot-Building Kit.

It does take absolutely forever to build any of these projects, but there are stages along the way where you can stop and play with what you’ve got so far.

And, if you are clever, you can combine the Lego Boost parts that come with the kit with other Lego objects and make more different things. For example, if you happen to have the LEGO City Arctic Scout Truck (60194) , which is in and of itself a fun LEGO kit, you can combine some of the Boost parts with this kit to make something special. Like this:

But, the problem with that project, and several like it, is that even on the LEGO boost site, there is relatively little information on how to do it. Not that you necessarily want step by step instructions. You really want to learn how to hack the LEGOs with the Boost and have fun creating. But I think it is helpful to get a bit more guidance, to get farther with the first few stages of this sort of project.

And that is why Yoshihito Isogawa wrote The LEGO BOOST Idea Book: 95 Simple Robots and Hints for Making More!. This excellent book has, as it says in the name, 95 specific ideas that come in the form of typical LEGO non-verbal visual instructions (but nicer looking than actual LEGO instructions) to do very specific things, like how to make a sliding door, how to launch rockets, that sort of thing. Each project comes with the code blocks specified to make it work.

In a way, deploying many of the ideas in this book, and using them as part of an overall LEGO build you’ve otherwise got going, may be more fun than the Robot itself, especially after you’ve messed around with the robot for a few weeks.

For example, we have a large and complex LEGO Angry Birds Kit, which includes an angry bird launcher that uses basic finger power like a lever. Not any more! We are going to build an actual rocket launcher that launches the angry birds, you betcha!

Now, I want to be clear about something. All of the parts that the The LEGO BOOST Idea Book uses in its descriptions are part of the LEGO Boost kit itself (#17101). But the principles laid out and the design ideas could easily use other bricks from your general collection. This give you the best of both worlds: Total functionality using the book itself as an add on to your Boost, adding significant value to that expensive kit for only a few bucks more AND a way to leverage all those other books, because you can extend the projects pretty easily with your own imagination.

I guess I would say that if you get a LEGO Boost Kit, you really should get this book along with it. Great gift for a kid this holiday season. Best ready to build robot on the market (possibly) with a truly meaningful extension.