Or: How to Entertain Little Kids for Hours for $5

A few weeks ago, I was grocery shopping with the kids. As we wheeled out of the frozen foods section, I noticed a big cooler full of dry ice for sale. I had seen it before, and thought it might be fun to do some experiments with the kids. But it was never the right time, and I thought I should probably research fun experiments before I bought any. Well, today I was taking care of the kids all day. And it was a beautiful day. Then I noticed the price. It was about $5 for a pound of dry ice. For $5, who cares if we haven’t done any preparation? It’s $5! We can’t afford not to try it!

It turns out it takes about 2 minutes of internet surfing to come up with plenty of fun stuff to do with dry ice. Here are the things we liked the best, and some things that were not that awesome.

Things that were awesome:

Put it in a pan of water

This is the most basic fun thing to do, and a lot of other cool experiments start with this basic one. Find an old pan, put a half-inch of water in it, and drop in a chunk of dry ice. Smoke everywhere! I used a metal pan, because I was concerned a glass pan might crack. I also put it on top of some cardboard, to insulate it from our glass tabletop. If you just leave a chunk of dry ice in the air, it will slowly sublimate, causing a small ‘smoke’ effect. The water speeds up the process by transferring heat faster, so it sublimates faster, making the smoke more dramatic. The water around the dry ice will eventually freeze, which slows down the process. You can knock the water ice off to get things going again. Which brings us to a word on safety. When I say ‘drop in a chunk’, keep in mind this stuff is seriously cold. It will stick to your hands and ‘burn’ your skin if you leave it on long enough. It won’t kill you to touch it, but we mostly used gloves or tongs to handle it.

Submerge it in a tub of water

Once you’ve watched the basic pan of water for a while, try adding enough water to cover the dry ice (or, throw some in a fountain, like we did). The dry ice is still sublimating, but now the ‘smoke’ forms bubbles under water, which come up to the surface and pop.

Add some bubble soap

If you’ve already got the dry ice submerged and making bubbles, add some soap. If things work just right, you’ll get smoke-filled bubbles that will leave the surface of the water, and then float off through the air.

Touch it with metal

If you press a piece of metal (spoons, screwdrivers and pennies all work well) against the dry ice, you’ll hear a high pitched screeching. Apparently, the gas forming around the metal pushes the metal away. Then the escaping gas pulls the metal back. This happen over and over and quickly enough to make a horrible noise. Kids love it.

Put in in apple juice

This is a great break when the kids are finally growing weary of the water pan experiments. “Let’s have some juice. Oh, look I put a little chunk of dry ice in your juice glass!” Now we’ve got bubbling juice, with spooky looking smoke on top. Don’t let them drink it until the dry ice is gone, but when it is, you now have carbonated juice. This was a huge hit.

Things that were not that cool:

Put some in a balloon

The idea here is you put dry ice in a balloon, tie it, and the dry ice inflates the balloon. First, it is very hard to get the dry ice into the balloon. It needs to be a small piece to begin with, and then it wants to stick to the rubber as you’re trying to push it in. I eventually got the balloon tied off, and it did partially inflate, but it was pretty unimpressive.

Put some in a Ziploc bag

This is the same idea as the balloon, but since the bag can’t stretch like the balloon, it should eventually explode with a loud kaboom. Since I had little children wandering around, I was very conservative with how much dry ice I used. It slowly inflated the bag. The bag then quietly ruptured. No kaboom. If I had put a bigger chunk in, along with some hot water, it probably would have worked as intended. Maybe next time.

The Takeaway

Overall, the kids (and dad) loved it. It turns out a pound was way more than we needed to have fun for hours. A half-pound probably would have been plenty. Also, it will last all day in a regular cooler, so you don’t have to stress about getting things prepared quickly. Was it worth $5? Absolutely. We may buy some more at Halloween for spooky witch cauldron effects.

Are there any awesome tricks I should’ve done, but didn’t? Let me know in the comments, because I’ll probably do this again someday.

The internet is the greatest tool for sharing information in the history of humanity. I particularly love it for finding out how to do new things, or how to do old things better. I’ve done a huge amount of work on my cars that I never would have accomplished without electronic help. And in that spirit, I try to give back. When I learn something new, or see someone who needs help, I’ll post it on a forum, or sometimes even write a how-to article. But with the rise of information sharing came the rise of the hater, which is what got me writing today.

Credit: Leimenide on flickr

A few months ago, I posted an article on how to do a simple fix for my microwave. It was easy, it saved me literally hundreds of dollars, and I thought it would probably help out other people. Knowing that we’re talking about working around electricity, I threw in a broad caution statement:

“A word of warning: if you are not experienced taking apart electronics, don’t get in over your head. Use common sense, make sure to unplug everything, be careful, and take pictures to remember how things go back together.”

But that didn’t stop someone from chiming in to tell everyone that the sky was falling and that it was probably my fault. The comment was well-written, and unfailingly polite, but I felt like it went too far:

“Please permit me to preface what I’m about to say that I’m a trained appliance tech. Microwave ovens, along with televisions and computer monitors, are very dangerous devices for an unskilled person to work on and one tiny slip could send you to the hospital ER or worse. Microwave ovens have a high voltage power supply that produces, on average 2,000 volts which is rectified (changed from AC to DC) which powers the magnetron tube, which generates the microwave radiation that cooks your food. The danger comes from the fact that microwave ovens contain an oil filled high voltage capacitor (the oval shaped can located right below the fuse in your picture) that can hold a charge for days, even weeks, after the oven has been unplugged. That voltage and amperage is enough to stop your heart. Modern ovens contain a bleeder resistor built in the capacitor that neutralizes the charge on the capacitor’s plate when the unit is shut off, but those resistor can fail and for that reason the capacitor must be properly discharged before the oven is safe to work on. Unless one is trained to work on high voltage circuitry one should ask him or herself is the money I save by doing it myself worth my life?

Your article is well written but the lack of adequate precautions about the potential for electrocution could get a beginner seriously hurt. Just removing the oven’s shell will be getting them in over their head.”

My first reaction was to get defensive and argue. But I resisted that urge and decided to sleep on it before I replied. As I said, the comment was not-trollish or baiting, but I did have a question about his motives. This commenter says he is a trained appliance technician, and is criticizing an article that tells people how to fix their microwave without his help. Obviously there is potential financial motivation for him.

But let’s give him the benefit of the doubt and assume he is genuinely just concerned about people getting hurt. This is the part the irked me the most about his comment. The underlying thought process is that since some idiot may get hurt doing something stupid, we must assume everyone is that stupid, and try to protect them from themselves. The world is full of smart, capable people. To dumb down the internet just to protect the least capable people hurts everyone. It reminds me of the short story Harrison Bergeron; did we learn nothing from that? Or are we not allowed to read that in school anymore? This is the reason that car and appliance manuals no longer have any useful repair information in them, for fear that someone will get hurt and sue the manufacturer. Which is what sends us looking on the internet for actual help on how to do fix things.

I feel like I may be getting overly worked up about one small comment, but there really is a bigger issue at stake. I don’t WANT people to hurt themselves. But more importantly, I don’t want the entire planet to be deprived of information for the fear that one person may misuse it.

Am I way off base here?

Growing up in the 80’s, I heard a lot of promises that Virtual Reality was right around the corner, the same way my parents had been promised flying cars. Any day now, I was going to be plunged right into a William Gibson novel, a virtual cowboy avoiding ICE.

Google Cardboard assembled

When the Oculus Rift came out in 2012, it created some buzz, but at $350, it was too expensive if you were just casually curious. Then in 2014, google jumped in the game and showed us that VR didn’t have to be out of reach. A smartphone has enough computing power to show stereoscopic images, and you can build a headset to hold it very cheaply. Google gave away the original Google Cardboard kit at their developer conference, and caused a minor internet sensation. Unfortunately, probably due to the ongoing feud between Google and Apple, the Google Cardboard kit was made specifically for android phones, and if you had an iphone you were out of luck. But, true to the DIY ethos of the web, creative people found workarounds.

I was intrigued enough to start digging in. If I could try it out for a few dollars, why not? Here’s what I did, how it worked, and what you need to know to try it yourself.

What you need:

First of all you’ll need the cardboard itself. I used the original DIY cardboard templates from google, which you can download here. You can buy kits premade for about $30 from that site also, but I was going for the lowest cost solution. Be aware that you want E-flute cardboard, which is about 1/16″ thick. This is thinner than the normal corrugated cardboard you’ll find in most shipping boxes. I found enough in various non-shipping boxes that I had sitting around. I’ve read that pizza boxes are also the right thickness.

Google also lists a bunch of other stuff you will need: lenses, magnets, Velcro, rubber bands, NFC tags, etc. You won’t actually need most of the stuff. The magnet and rubber band are used to make an input for specific android apps. If you’re doing this with an iphone, that won’t work, so you don’t need to bother. You will need lenses. I got mine from Unofficial Cardboard for about $10. I had some Velcro left over from other projects, so that was essentially free.

Google Cardboard pieces cut out

Next, I printed out the Google template onto 11″x17″ sheets of paper and taped them to my cardboard, and carefully and painstakingly cut the shapes out. This took probably 2 hours spread out over several days. I had the best luck with a large razor-blade style box cutter for the long straight cuts, and a small xacto knife for the smaller detailed features. Note that you don’t actually have to glue the template to the cardboard.

Once the shapes were cut out, it was just a matter of folding them up correctly. The online instructions are not super clear, so hopefully my pictures will help with any confusion. Be sure to put the interior pieces in correctly to hold the lenses in place. One good tip I picked up from Unofficial Cardboard: put a piece of scotch tape right where your forehead touches the cardboard. Otherwise it’ll get unpleasantly greasy surprisingly quickly.

Assembling Google Cardboard

Finally it was time to try it out. I downloaded several iphone apps to try out. As of this writing, the easiest way to find VR apps on the iTunes store is to search for Durovis Dive (which is an $80 plastic version of what you just built out of cardboard). The good news is that the apps for the Durovis Dive work on the iPhone. UPDATE: Another good place to find iPhone compatible VR apps is here on the Unofficial Cardboard site.

For an iPhone 6, you’ll probably need to take your phone out of its case for it to fit in the cardboard. An iPhone 5 with a thin case may fit fine, I don’t know. Start the app, then put the phone in the cardboard, and then hold the cardboard up to your face. Here are my impressions of the apps I’ve tried so far:

Dive City Coaster:

You are riding a roller coaster, and you can look around by turning your head. The graphics aren’t spectacular, but I still got a little bit of motion feeling in my stomach. This is the app you’ll show to your friends first, because it requires no explanation or practice. But once you see it a couple of times yourself, you’ll be bored. Still, I tried this out sitting in a swivel chair, and I was surprised to see which way I was facing when I took the cardboard off. I give it 4 stars as a quick demo.

The Height:

This one is an actual game, with things to do. You look down at a little icon at your feet, and it causes your avatar to walk in the environment. There are obstacles and goals, so this one actually merits some repeated play. 3 stars.

Kris Menace Virtual Edition:

This app is a step up in graphics from the others, and it does use headphones or earbuds to add surround sound to the experience, but there isn’t really anything to do in the app. 2 stars.

Moorente:

Duck hunt in 3D. Very basic, but there it is a legitimate game, and easily played, so this one becomes another easy one to show other people how VR works. 3 stars.

DiveZombie:

A dark first person shooter where you look at zombies to shoot them. Not bad. 3 stars.

Space Slider VR:

You are moving forward along a wireframe path trying to collect little pellets. The concept is not bad, but I found the navigation extremely frustrating. Your steering inputs do almost nothing until they suddenly do way too much. 2 stars.

Roller Coaster VR:

Another roller coaster. This one has prettier scenery (you’re in the jungle), but the ride itself is a little less immersive to me (I didn’t feel it in my stomach as much). Overall very good, and a toss up between this one and Dive City Coaster. 4 stars.

Is it worth doing?

For me, yes. Overall, for the time and money invested, this iOS Cardboard experiment was a pretty good sampling of the current state of budget VR. You can see the potential for great things to come when more developers get interested. But with the quality of the apps available right now, I’m glad I didn’t spend any more than I did on a headset. I’ve read that there may be some new toys available using WebGL on Safari in iOS 8. I’ll do an update if I find any good ones.

Silver cube, scrambled

When the Rubik’s Cube originally came out in the 1980s I was 10ish. I played with one, and could solve a side and the next level. But I could never do the full cube without laboriously paging through a solution book my Dad bought. Once the furor died down, I moved on to other things. Then, last year, a couple of friends picked the cube back up. I was included on their emails as they kept beating each other’s fastest solve times. Finally, I couldn’t resist and started asking questions. What you need to know to solve the classic cube is Bad Mephisto. He does the best job I’ve seen of teaching you how to solve the classic cube. Go to his site and learn the 5 algorithms.

Faster Cubes

I didn’t want to learn to solve the cube fast, I just wanted to learn to solve it. But once you can solve it reliably, you’ll probably want to go faster. The classic cube is fine, but if you want to go faster, it will eventually hold you back. There are ‘speed cubes’ that spin more easily, and also have clipped corners, that allow you to start a turn without the edges being as precisely aligned as the original cube requires. They are also stickerless, so no more peeling stickers. So I got this one from Amazon. With that cube, I average about 2:00 – 2:30 to solve, with a best time of 1:26.

More Challenges

Which brings us to the beauty you see here. When solving the basic cube is no longer daunting, you may find yourself looking for new challenges. This beautiful cube solves with same algorithms as the normal 3×3 cube. But instead of each side being a different color, each side is a different size and shape, so it’s a fun challenge to figure out how to map ‘size and shape’ information onto the color algorithms you already know. And when it’s scrambled it looks fantastic, like a bizarre futuristic building. I got it here on Amazon for about $5, and it always starts a conversation whenever anyone sees it.

Silver cube solved

Another picture from my trip to Berlin. When we saw these parked on the street, my inner car-guy took notice. A discussion ensued about which was worth more. I believe we are looking at a Mercedes SLS AMG here, that sold for about $202,000 new. I have no idea what prices are like for older Rolls Royces.

Anyone have a guess?