The files require Adobe Acrobat Reader.
Note on how to print the files: Make sure the files print the correct size! At the print window, set under Page Handling the Page Scaling to NONE.
You might wish to print this on transparency paper.
If you like, you can cut out and paste the ruler on some cardboard or an empty cereal box.
Kids, ask your parents permission before beginning this project.
To measure with the ruler, line the object up to the first line of the ruler where there would be a 0. That's the starting point. Then see how far down the ruler it goes.
In this example the red line is 2 inches long.