Name the scientific law that is illustrated in these experiments

Object
Mass (kg)
Initial Velocity (m/s)
Final Velocity (m/s)
Ball 1 (m1)
1.00 kg
1.20 m/s
-0.80 m/s
Ball 2 (m2)
-0.30 kg
-0.30 m/s
0.70 m/s

The scientific law illustrated in these experiments is the Law of Conservation of Momentum.