After reading the poem 8 A.M. Shadows by Patricia Hubbell in the book Sing a Song of Popcorn, we were inspired to measure shadows for math. We actually ended up doing more math that I thought we would.
First my son made a chart to record the lengh of his shadow each hour throughout the day. He set his alarm clock each hour as a reminder, but something happended at 3:30 and the shadow length was not measured. This actually ended up being a really good thing.
I helped him make a line graph of his data, and then he estimated what his shadow length would have been at 3:30. In the morning the following day he figured out how many hours and minutes 3:30 was from the current time and set his alarm clock. At 3:30 he measured his shadow length and compared the result with his estimate. This simple project ended up being very fun and educational for him.