diff --git a/js/gravity-force-lab/model/Mass.js b/js/gravity-force-lab/model/Mass.js
index e3f69337..ffa3886f 100644
--- a/js/gravity-force-lab/model/Mass.js
+++ b/js/gravity-force-lab/model/Mass.js
@@ -16,8 +16,8 @@ define( function( require ) {
   //constants
   var DENSITY = 150; // kg/m^3
   var CONSTANT_RADIUS = 0.5; // in meters
-  var CONSTANT_MASS_COLOR = new Color( 'thistle' );
-  var COLOR_REDUCTION_CONSTANT = 2500; // empirically determined
+  var CONSTANT_MASS_COLOR = new Color( 'indigo' );
+  var COLOR_REDUCTION_CONSTANT = 1000; // empirically determined
 
    /**
    *
@@ -43,7 +43,7 @@ define( function( require ) {
         self.radius = self.calculateRadius( mass );
       }
       else{
-        self.baseColor = CONSTANT_MASS_COLOR.colorUtilsDarker( mass / COLOR_REDUCTION_CONSTANT );
+        self.baseColor = CONSTANT_MASS_COLOR.colorUtilsBrighter( 1 - mass / COLOR_REDUCTION_CONSTANT );
       }
     });
 
@@ -54,7 +54,7 @@ define( function( require ) {
       }
       else{
         self.radius = CONSTANT_RADIUS;
-        self.baseColor = CONSTANT_MASS_COLOR.colorUtilsDarker( self.mass / COLOR_REDUCTION_CONSTANT );
+        self.baseColor = CONSTANT_MASS_COLOR.colorUtilsBrighter( 1 - self.mass / COLOR_REDUCTION_CONSTANT );
       }
     });
 
diff --git a/js/gravity-force-lab/view/ControlPanel.js b/js/gravity-force-lab/view/ControlPanel.js
index 755bc572..4fc21a32 100644
--- a/js/gravity-force-lab/view/ControlPanel.js
+++ b/js/gravity-force-lab/view/ControlPanel.js
@@ -43,7 +43,7 @@ define( function( require ) {
     // init position element
     controlMass2.left = controlMass1.right + 50;
     controlShowValues.left = controlMass2.right + 50;
-    resetAllButton.centerX = controlShowValues.centerX;
+    resetAllButton.right = controlShowValues.right;
     resetAllButton.top = controlShowValues.bottom + 15;
   }
 
diff --git a/js/gravity-force-lab/view/MassObject.js b/js/gravity-force-lab/view/MassObject.js
index b927e652..f729509f 100644
--- a/js/gravity-force-lab/view/MassObject.js
+++ b/js/gravity-force-lab/view/MassObject.js
@@ -183,6 +183,13 @@ define( function( require ) {
       self.massCircle.fill = new RadialGradient( radius * 0.6, -radius * 0.6, 1, radius * 0.6, -radius * 0.6, radius )
         .addColorStop( 0, baseColor.colorUtilsBrighter( 0.5 ).toCSS() )
         .addColorStop( 1, baseColor.toCSS() );
+      //debugger;
+      if ( model.constantRadius ) {
+        //self.massCircle.stroke = baseColor.colorUtilsBrighter( 0.5 ).toCSS();
+        self.massCircle.stroke = baseColor.colorUtilsDarker( 0.15 );
+        //self.massCircle.stroke = 'black';
+      }
+
     } );
     redrawForce();