Interactive Science exhibits, ideated and fabricated to inclucate and invigorate the young minds about Science !!
In this model, there are two discs. Both have same diameter. One of the disc has concentrated mass at the centre while the other disc has more mass away from its centre. Allow the discs to start rolling simultaneously.
What did you observe?
The disc with bulged centre reaches the destination first.
The science behind it :
Due to concentration of more mass nearer to its rotating axis, the first disc gains more angular velocity and hence more angular momentum. Thus it reaches the bottom first.