Anyone know how to teach students about the blockchain using physical objects?

[Futureshock]

I'm looking to teach a bunch of students (18+) how the blockchain works. But I want it to be a hands-on session rather than a talk in front of a whiteboard.

Has anyone got any good ideas how to do this? I'm thinking about starting with everyone in a room being given matchsticks that represent bitcoins. People are then asked to pretend to trade with each other and exchange matchsticks. Once they do this, those that have received matchsticks put these into a shoebox - and receive a knife in return. 

The shoebox has a secret number stuck face down on the lid, written in the form of a tally mark - http://en.wikipedia.org/wiki/Tally_mark. I then ask people around the room to race each other writing out numbers from 1 upwards (in the form of tally marks). The winner who gets to the number first is then rewarded with 25 new matchsticks. And the summary of transactions is written on top of the shoebox.

The shoebox is then sealed with sellotape and can only be opened by someone who has a knife (who can only ever take out their own matchsticks from the box).

And repeat the process, with each additional shoebox that is put on the table every 10 minutes being physically stuck together and every single transaction recorded on the lid.

OK, it's maybe a little bit rough. It certainly misses out some of the points (i.e. having bitcoins as physical items rather than a record of UTXO's). But I think it might be a fairly simple way to introduce people to the blockchain.

If there's any great ideas for how to achieve something similar out there (i.e. taking it off the whiteboard and onto a table), please let me know! I think that this sort of thing might be really useful for hooking people into the concept in the very early stages.

Thanks guys 

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[neoneros]

You could try to explain it using the Two Generals' Problem(or the Byzantine)  http://en.wikipedia.org/wiki/Two_Generals%27_Problem

The matchsticks in the box seem nice, you could divide the class into miners and wallets, the miners pass the boxes, the wallets send the sticks arround?

[Futureshock]

You could try to explain it using the Two Generals' Problem(or the Byzantine)  http://en.wikipedia.org/wiki/Two_Generals%27_Problem

The matchsticks in the box seem nice, you could divide the class into miners and wallets, the miners pass the boxes, the wallets send the sticks arround?

Thanks - my original instinct had been to stay away from the Byzantine Generals Problem at this stage because I've watched many people trip over themselves when trying to explain it. However, you might just be right - it could be a very different proposition if you set up physical objects which represent the actual generals/city etc.

I guess if you give the class the freedom to decide whether to trade, mine or a combination of both, then there might be some way of starting to show what the trade-off is between spending your time writing numbers in a race to win (mining) or trying to make a profit on the trading things for matchsticks (using bitcoin).

[monsanto]

light some fiat on fire 

[Futureshock]

light some fiat on fire 

Then we risk getting into that whole 'proof of burn' debate....think I might leave that until lecture 2 

[bg002h]

At a Minneapolis bitcoin meet up, the organizers did a manual implementation of a ledger where people were given a few dollar bills (everyone's balance known by all), called out their transactions (Bob gives Sally $2), exchanged dollar bills, and everyone recorded the transaction. The organizers then took the dollar bills away and the exercise continued.

This doesn't address the proof of work concept very well, but it shows the value of the ledger.

[Futureshock]

At a Minneapolis bitcoin meet up, the organizers did a manual implementation of a ledger where people were given a few dollar bills (everyone's balance known by all), called out their transactions (Bob gives Sally $2), exchanged dollar bills, and everyone recorded the transaction. The organizers then took the dollar bills away and the exercise continued.

This doesn't address the proof of work concept very well, but it shows the value of the ledger.

Good idea, I guess in particular that brings across the fact if everyone holds the same records, it's impossible to unilaterally alter the ledger fraudulently. I'm keen to get the whole experience as 'touchy feely' as possible. Ideally, the simpler it is, the more potential there is to start rolling this method out into younger age groups as well which could yield an even more valuable longer term result when it comes to adoption.

[Lethn]

Just get some computers and show them the mining process? Lol The problem is what you're trying to explain is quite complicated backend stuff and I don't know if it can be that simplified, it's pretty funny seeing news journalists try to do it all the time, Bitcoin is a complicated technology.

I think the best way to get them to understand it personally is to just get them to use it, that's how I did it.

[GingerAle]

hrm, well you need something that you can build but you can also take a representation of in order to build the next something your going to build.

you could do this:

everybody exchanges something, and its all written down (on 3X5 index cards, or something the same size as a polaroid)

you arrange these index cards on the ground. Someone stands up, takes a polaroid of the collage (the equivalent of doing taking the hash of the block)

You then put this new polaroid on the ground, and have everyone make some new transactions. Lay the transactions on the ground with the old polaroid, take another polaroid.


You could even mimic proof of work somehow (and the differences in mining hardware) by assigning some students to be miners and giving them different power magnifying glasses. They could analyze the polaroid (the second one) in an attempt to "hash" the transaction block to find 20 values that add up to 75 or something.

[koinvict]

I like to explain it as a system of receipts.

Each receipt represents a transaction (naturally).  And we stack the receipts one on top of another.  We take those stacks (after 10 min of stacking) and place them in a box (a block).  Over time, those boxes are stacked on top of each other to form the blockchain.

We can program "accountants" to go in and verify the transactions and do all sorts of cool stuff to look at the data. 

You can get as detailed as you want by writing what exactly goes into a transaction on the receipts.

[kwiktech]

I like to look at bit coin as a gate locked with pad locks.

Addressees = padlocks

A whole bunch of padlocks linked together...

[neoneros]

you need something that you can build 

you could use LEGO for building the chain, use blocks of different colors and have the miners build them and check every time if the chain/blocks are alike every time someone adds a transaction

[gjgjg]

knives in a classroom?! they must be good kids!   

how about: put a math problem on the white board, the kids need to raise their hands to solve it. it gets increasingly harder as each person does it (2+2= ... then 2+2x5= ... then 2+2x5+1=... etc).

when they do it they get a few blocks of lego, that kid writes a codes on them in eraseable marker pen and adds them to a lego board (the lego boards were used as grounds and street to build stuff from). the board can be put somewhere where everyone can see.

once the math problems start to get hard, tell them they can buy blocks with money from the guys that solved problems before (each kid can get some matchsticks at the start for fiat). for this part they can now start to wander around and ask kids to sell them. the lowest price can be written on the white board, but they dont have to sell them for that price!

when they buy blocks, they get to erase the 'code' or name written on the lego block they now own, and the new owner writes their own code on it. maybe to record the history of the block, they could stick a posit-it there or maybe add a note to the block if theres space...?

the ones who have blocks on the lego board get to set prices, so the buyers can decide to either solve the latest math problem to get a block or use matchsticks to buy some. if the kids cant find a buyer at the guide price written on the board they can shout out / raise their hands and declare the new prices - if it goes up weve got a rally!

the winner is the one who has most blocks (and matchsticks converted into blocks count)... if there is a winner to this lol, but kids need incentives i guess.

this could be done in an orderly way taking it in turns or maybe once the first blocks are mined and kids start to sell they could start to freely walk around to emulate a market place more.

not sure its much better than the op idea, but the blocks of lego on the lego board is more clearer concept to the blockchain imho. its also a little more straight forward - imo.
i know it focuses on the market place aspect a but more, but thats what btc is trying to be in some respects - an alt marketplace.

in the end you can show the kids the real world version on a pc so they really get the idea.

[Futureshock]

you need something that you can build 

you could use LEGO for building the chain, use blocks of different colors and have the miners build them and check every time if the chain/blocks are alike every time someone adds a transaction

Definitely like the lego idea, thanks. It could be easier to start off that way. Each student could get a square block made up of varying numbers of lego pieces to represent 1 BTC - which is then clearly divisible, to an extent, into its constituent parts. There's a point that can be discussed around the fact that bitcoins then aren't perfectly fungible (i.e. when you move (or spend) them you're spending some specific bitcoins). Maybe the lego could then get put into the shoeboxes.

[Bitcoinpro]

light some fiat on fire  

Then we risk getting into that whole 'proof of burn' debate....think I might leave that until lecture 2  

a ltc proof of burn

would make the exchanges hysterical

[Futureshock]

I like to explain it as a system of receipts.

Each receipt represents a transaction (naturally).  And we stack the receipts one on top of another.  We take those stacks (after 10 min of stacking) and place them in a box (a block).  Over time, those boxes are stacked on top of each other to form the blockchain.

We can program "accountants" to go in and verify the transactions and do all sorts of cool stuff to look at the data. 

You can get as detailed as you want by writing what exactly goes into a transaction on the receipts.

Maybe if we're exchanging lego, the person who puts their newly acquired lego into the shoebox receives a receipt at the same time which contains the number of lego pieces deposited plus a random reference. A copy of the same receipt is also given to everyone who is acting as a miner. If the student then wants to spend that lego/bitcoin in the future, they have to go round each of the 'miners', display the random reference on the receipt; the miner checks it out and, if so, lets them unseal the shoebox with the knife.

Hmmm, this is getting a bit more complicated now....