Long cardboard tube, such as an empty roll of wrapping paper, to make your ramp. It should be at least two-and-one-half feet long. A thin book or small wood block to raise one end of your ramp. It ...
Unfortunately, this book can't be printed from the OpenBook. If you need to print pages from this book, we recommend downloading it as a PDF. Visit NAP.edu/10766 to get more information about this ...