How can use AddExplosionForce to explode scattered objects?

I have a central cube named "Explosion" sitting on a plane with 4 cubes placed around it. I apply the following script to Explosion:

var radius = 100.0; var power = 1000.0; function Start () { Debug.Log("start"); // Applies an explosion force to all nearby rigidbodies var explosionPos : Vector3 = transform.position; var colliders : Collider[] = Physics.OverlapSphere (explosionPos, radius);

 for (var hit : Collider in colliders) {

     if (!hit)
         continue;
     if(hit.name=="Explosion")
         continue;
     if(hit.name=="Plane")
         continue;     
     if (hit.rigidbody)
         Debug.Log(hit.name);
         hit.rigidbody.AddExplosionForce(power, explosionPos, radius, 10.0);
 }

When I run this, the four cubes barely move at all. I increase the power value, but it has no affect. When I put the cubes at the same location as the Explosion cube, they appropriately explode, but I want to be able to have them placed randomly.