How Long Did I...?

Yesterday I stayed at work until 6 trying to make a lesson to help my fourth graders understand elapsed time. When I got home I spent another hour making an 11 foot elapsed time ruler (12 sheets that are 11 inches each=12 sheets x 11 inches=132 inches 132 inches / 12 inches=11 feet). After today's lesson, I still realize elapsed time is such a hard concept to teach and an even harder concept for my 9, 10, and 11 year olds to learn. After a week of teaching the skill, I still have some students who just don't get it! Any suggestions would be greatly appreciated.

Overall, my students enjoyed the lesson. Students worked in stations--one group at the Promethean Board, one group on computers, and one group with me and my giant elapsed time ruler. I heard several "this is fun" comments. I am happy that my time and effort makes mathematics fun, but I want my students to get it. It is very frustrating and disheartening that some students just don't get math.

Tomorrow is another day and maybe the light bulb will turn on then.

I leave you with this:

I started working on the lesson at 4:40 after tutoring let out. I left school at fifteen minutes to six to go home. I then worked at home on the lesson for one more hour. How long did I work on the lesson?