A neat lab I did in high school was taking a tube and filling it halfway with distilled water, and topping it off with absolute ethanol. (Carefully adding so they don't mix). The tube was then sealed and we mixed the liquids by inverting the tube multiple times. It was pretty neat seeing a good deal of empty space form as the two liquids mixed. I think it would be much easier to make a 70% ethanol solution based on weight than volume.