1. Place the object on the pan.

2. Move the 500 gram rider to the first notch which causes it to drop.

3. Then move it back one notch, causing the pointer to rise.

4. Move the 100 gram rider to the first notch which causes it to drop.

5. Then move it back one notch, causing the pointer to rise.

6. Slide the 10 gram rider to the position which brings the pointer to zero.

7. The mass of the object is the sum of all the values on the rider's positions -
     read directly from the beams.  (ADD)