# You Be The Judge

We were planning a Lego party for our son. One activity was seeing how many pennies one could float in a Lego boat. In the event of a tie, would the winner be the one with the lightest boat (i.e., being amazed such a light boat can carry such a load) OR the one with the heaviest boat (i.e., being amazed that such a heavy boat didn’t sink with the load)! Which one would you pick as the tie-breaker???

Well you should have different categories – enough categories so that everyone who builds a boat will win in some way (in order to ensure that no child’s fragile self esteem is shattered).
Seriously, nothing wrong with different categories or classes of boats. Or you could do a formula – weight cargo divided by weight of boat. That would give you a way to compare across all different sizes of boats. It sounds like a fun and educational activity.

Have you tried actually building some different Lego boats and seeing how many pennies they will hold? Maybe experimenting a bit will give you some ideas about what factors are relevant here.

Lightest boat. It has the largest load-to-boat weight ratio.

ETA: You should have some requirement limiting the boat’s size. Maybe a maximum length, width, and height.

If the tie occurs because both boats held exactly the same number of pennies, then I’d be inclined to declare the lightest boat the winner. The lighter boat implies that you have a more elegant solution than a heavier boat that may have just used a brute force design.

Very good thoughts, all! We’ll take all suggestions into consideration. (BTW, we’re just starting to experiment ourselves.)

Consider the following two boats:

1. A Lego boat made from just 9 tiny Lego blocks, and holds 1,000 pennies.
2. A Lego boat the size of a car, and holds 1,000 pennies.

Give each child the same number and shapes of pieces, or create classes of those and have a winner in each one. If you do have to weigh the boat, weigh it before you use it, to eliminate the water from playing a factor. Further, I would go with the highest penny:weight ratio rather than just weight, but also set some kind of reasonable bounds which you can experiment with ahead of time. For instance, must float at least 5 pennies, but you won’t attempt to put more than 50 on it or whatever. But really, given a party that would have this as an activity, why can’t you just have a tie?

In the event of a tie; declare it a “tie”, award prizes to both winners and move on to the next bit of fun.

If you don’t keep the party moving, you’re going to rapidly lose the interest of those kids who aren’t immediately involved.

Determine the Froude number for each boat. The kid who guesses the difference between the two numbers wins.

Absolutely this!
Yeah, I know this is the Dope, and knowledge is what we do, and no nit is to small to pick, and without a cite you’re a nobody; and dammit, I love this place for all those reasons.

But I also like to play Lego with kids.
And sometimes, just sometimes, seeing a bunch of 7 kids smile and have fun is more important than all the Doper wisdom in the world.

I like this idea, but not because of the self esteem thing - just because it opens up the possibility of more fun - you could have minor prizes for ‘fastest sinking’, ‘most spectacular destruction’, ‘made sense on the drawing board’ etc.

This idea is a winner!
Can I come to the party ,too?
Oh, I forgot. This is the Dope.We should be talking about how to turn a birthday party into an educational opportunity to teach Froude numbers and Archimedes principle.
Sorry.

But I s’pose we can still talk about that stuff---- after we destroy the boats.

Why not just throw one more penny on each of the boats, and whichever one sinks slowest wins? That way you have a winner, and we still get to sink the boats!