Negative mass was something physicists never thought they would find – let alone create. For more than a century, physics has operated on the foundation that mass is always positive. From Newton’s ...

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 ...

Many a high school smoker has built a gravity bong on the back porch to get stupid high on some mid-grade marijuana, but whatever contraption you rigged up with hot glue and soda bottles probably didn ...