Promoting Students' Logical and Critical Thinking

One of the things that I've noticed over the years is a decline in logical thinking.  Last year, I decided I was going to try to build some logical thinking activities into my classroom without students realizing what they were doing (I know...so sneaky!).  At CAMT13, my teaching partner and I came across the perfect "puzzle" to satisfy this need.

The Ultimate Puzzle, as it's called, is quite challenging.  It took my daughter (who I must admit is very bright - she is a junior in the Dulles High School Math and Science Academy) spent hours on it the first time she tried.  Once she got the hang of it, then she set out to see how many different ways she could put the puzzle together.

So...in my classroom, I had a couple of students finish a test quickly.  They asked what they could do and I sent them to the hallway with a puzzle.  They spent the rest of the class period attempting to get a 4 x 4 puzzle put together!

Fast forward 2 weeks.  The first students to finish came and asked if they could go in the hall with the puzzles.  At one point I had 3 students in the classroom finishing tests and 24 students trying to get the puzzles put together!  I absolutely love it when students ask you if they can do something that they think is fun, but that I know will help develop their brains!

So far, we've been able to get a 3 x 3 square, but we haven't had any luck with the 4 x 4 square.  My students are determined, though, and I can't wait to see the excitement when they get there!

We also have some Brick by Brick puzzles that come with bricks and different pictures.  Students have to build a figure that matches the picture (similar to Tangram puzzles but three dimensional).

What do you do in your classroom to help build students' logical and critical reasoning skills?  I'm always looking for new ideas :)