diff --git a/js/common/model/masses/Barrel.js b/js/common/model/masses/Barrel.js
index 2c3dae85..be2bb0d7 100644
--- a/js/common/model/masses/Barrel.js
+++ b/js/common/model/masses/Barrel.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import barrel_png from '../../../../images/objects/barrel_png.js';
diff --git a/js/common/model/masses/BigRock.js b/js/common/model/masses/BigRock.js
index 16fcff22..01cc2936 100644
--- a/js/common/model/masses/BigRock.js
+++ b/js/common/model/masses/BigRock.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import rock6_png from '../../../../images/objects/rock6_png.js';
diff --git a/js/common/model/masses/CinderBlock.js b/js/common/model/masses/CinderBlock.js
index b4a59609..1f583597 100644
--- a/js/common/model/masses/CinderBlock.js
+++ b/js/common/model/masses/CinderBlock.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import cinderBlock_png from '../../../../images/objects/cinderBlock_png.js';
diff --git a/js/common/model/masses/Crate.js b/js/common/model/masses/Crate.js
index 57173f73..d9ad2642 100644
--- a/js/common/model/masses/Crate.js
+++ b/js/common/model/masses/Crate.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import woodCrateTall_png from '../../../../images/objects/woodCrateTall_png.js';
diff --git a/js/common/model/masses/FireExtinguisher.js b/js/common/model/masses/FireExtinguisher.js
index af11562a..0660f924 100644
--- a/js/common/model/masses/FireExtinguisher.js
+++ b/js/common/model/masses/FireExtinguisher.js
@@ -1,4 +1,4 @@
-// Copyright 2013-2021, University of Colorado Boulder
+// Copyright 2013-2023, University of Colorado Boulder
 
 
 import fireExtinguisher_png from '../../../../images/objects/fireExtinguisher_png.js';
diff --git a/js/common/model/masses/FireHydrant.js b/js/common/model/masses/FireHydrant.js
index d609fa22..e7f9f630 100644
--- a/js/common/model/masses/FireHydrant.js
+++ b/js/common/model/masses/FireHydrant.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import fireHydrant_png from '../../../../images/objects/fireHydrant_png.js';
diff --git a/js/common/model/masses/FlowerPot.js b/js/common/model/masses/FlowerPot.js
index 8cb08389..0e7e7641 100644
--- a/js/common/model/masses/FlowerPot.js
+++ b/js/common/model/masses/FlowerPot.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import flowerPot_png from '../../../../images/objects/flowerPot_png.js';
diff --git a/js/common/model/masses/LargeBucket.js b/js/common/model/masses/LargeBucket.js
index c5e3cafb..2bcd0fc7 100644
--- a/js/common/model/masses/LargeBucket.js
+++ b/js/common/model/masses/LargeBucket.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import metalBucket_png from '../../../../images/objects/metalBucket_png.js';
diff --git a/js/common/model/masses/LargeTrashCan.js b/js/common/model/masses/LargeTrashCan.js
index 2d24c069..a36b6060 100644
--- a/js/common/model/masses/LargeTrashCan.js
+++ b/js/common/model/masses/LargeTrashCan.js
@@ -1,4 +1,4 @@
-// Copyright 2013-2021, University of Colorado Boulder
+// Copyright 2013-2023, University of Colorado Boulder
 
 
 import trashCan_png from '../../../../images/objects/trashCan_png.js';
diff --git a/js/common/model/masses/MediumBucket.js b/js/common/model/masses/MediumBucket.js
index 32041c61..614fa98b 100644
--- a/js/common/model/masses/MediumBucket.js
+++ b/js/common/model/masses/MediumBucket.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import yellowBucket_png from '../../../../images/objects/yellowBucket_png.js';
diff --git a/js/common/model/masses/MediumRock.js b/js/common/model/masses/MediumRock.js
index 68776807..b4933178 100644
--- a/js/common/model/masses/MediumRock.js
+++ b/js/common/model/masses/MediumRock.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import rock1_png from '../../../../images/objects/rock1_png.js';
diff --git a/js/common/model/masses/MediumTrashCan.js b/js/common/model/masses/MediumTrashCan.js
index 0249334f..509ac7a9 100644
--- a/js/common/model/masses/MediumTrashCan.js
+++ b/js/common/model/masses/MediumTrashCan.js
@@ -1,4 +1,4 @@
-// Copyright 2013-2021, University of Colorado Boulder
+// Copyright 2013-2023, University of Colorado Boulder
 
 
 import trashCan_png from '../../../../images/objects/trashCan_png.js';
diff --git a/js/common/model/masses/MysteryMass.js b/js/common/model/masses/MysteryMass.js
index b3663295..673912de 100644
--- a/js/common/model/masses/MysteryMass.js
+++ b/js/common/model/masses/MysteryMass.js
@@ -1,4 +1,4 @@
-// Copyright 2013-2022, University of Colorado Boulder
+// Copyright 2013-2023, University of Colorado Boulder
 
 /**
  * Type that defines 'mystery masses', which are masses whose mass value is
diff --git a/js/common/model/masses/PottedPlant.js b/js/common/model/masses/PottedPlant.js
index 96fbaa43..80e91f5e 100644
--- a/js/common/model/masses/PottedPlant.js
+++ b/js/common/model/masses/PottedPlant.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import pottedPlant_png from '../../../../images/objects/pottedPlant_png.js';
diff --git a/js/common/model/masses/Puppy.js b/js/common/model/masses/Puppy.js
index 1f19692c..adc4d604 100644
--- a/js/common/model/masses/Puppy.js
+++ b/js/common/model/masses/Puppy.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import puppy_png from '../../../../images/objects/puppy_png.js';
diff --git a/js/common/model/masses/SmallBucket.js b/js/common/model/masses/SmallBucket.js
index 45e3147d..67c3d837 100644
--- a/js/common/model/masses/SmallBucket.js
+++ b/js/common/model/masses/SmallBucket.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import blueBucket_png from '../../../../images/objects/blueBucket_png.js';
diff --git a/js/common/model/masses/SmallRock.js b/js/common/model/masses/SmallRock.js
index ebea984b..ab2bd79b 100644
--- a/js/common/model/masses/SmallRock.js
+++ b/js/common/model/masses/SmallRock.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import rock4_png from '../../../../images/objects/rock4_png.js';
diff --git a/js/common/model/masses/SmallTrashCan.js b/js/common/model/masses/SmallTrashCan.js
index 5df09ab9..6a1d545a 100644
--- a/js/common/model/masses/SmallTrashCan.js
+++ b/js/common/model/masses/SmallTrashCan.js
@@ -1,4 +1,4 @@
-// Copyright 2013-2021, University of Colorado Boulder
+// Copyright 2013-2023, University of Colorado Boulder
 
 
 import trashCan_png from '../../../../images/objects/trashCan_png.js';
diff --git a/js/common/model/masses/SodaBottle.js b/js/common/model/masses/SodaBottle.js
index 3fe056e6..98aa905d 100644
--- a/js/common/model/masses/SodaBottle.js
+++ b/js/common/model/masses/SodaBottle.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import sodaBottle_png from '../../../../images/objects/sodaBottle_png.js';
diff --git a/js/common/model/masses/Television.js b/js/common/model/masses/Television.js
index 0e4ea3df..35238337 100644
--- a/js/common/model/masses/Television.js
+++ b/js/common/model/masses/Television.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import oldTelevision_png from '../../../../images/objects/oldTelevision_png.js';
diff --git a/js/common/model/masses/TinyRock.js b/js/common/model/masses/TinyRock.js
index a7cd4d7f..d7c6ae50 100644
--- a/js/common/model/masses/TinyRock.js
+++ b/js/common/model/masses/TinyRock.js
@@ -1,4 +1,4 @@
-// Copyright 2013-2021, University of Colorado Boulder
+// Copyright 2013-2023, University of Colorado Boulder
 
 
 import tinyRock_png from '../../../../images/objects/tinyRock_png.js';
diff --git a/js/common/model/masses/Tire.js b/js/common/model/masses/Tire.js
index 29bc2143..2ca3efb0 100644
--- a/js/common/model/masses/Tire.js
+++ b/js/common/model/masses/Tire.js
@@ -1,4 +1,4 @@
-// Copyright 2014-2021, University of Colorado Boulder
+// Copyright 2014-2023, University of Colorado Boulder
 
 
 import tire_png from '../../../../images/objects/tire_png.js';