Today I had about ten minutes to prepare my lesson, I had to come up with an age appropriate graphing exercise. Google helped me to locate what I was looking for. Teach-nology had 40 different exercises in graphing I could have chosen from - I used a line graph with data I knew would form a straight line. There are plenty of worksheets and exercises that you can access for free. This is the data I used for my students.
There is no need to kill trees and spend time photocopying, you can use digital resources with a data projector like I did - I added a few questions on hypothesis and variables, got them to copy the table and graph the data. Teach-nology certainly seems to have a wide variety variety of worksheets in Math, Science, Art and Languages in all manner of topics.