diff --git a/js/intro/model/IntroModel.ts b/js/intro/model/IntroModel.ts
index 324eb84e..ad5677a5 100644
--- a/js/intro/model/IntroModel.ts
+++ b/js/intro/model/IntroModel.ts
@@ -38,7 +38,7 @@ export default class IntroModel extends MeanShareAndBalanceModel {
   public readonly meanVisibleProperty: Property<boolean>;
   public readonly tickMarksVisibleProperty: Property<boolean>;
 
-  public readonly numberOfCupsProperty: NumberProperty;
+  public readonly numberOfCupsProperty: Property<number>;
   public readonly meanPredictionProperty: Property<number>;
   public readonly meanProperty: IReadOnlyProperty<number>;
 
@@ -321,7 +321,7 @@ export default class IntroModel extends MeanShareAndBalanceModel {
    * @param range - the allowed waterLevelProperty range in each cup
    * @param waterLevelProperty - The property tracking the water level in each cup's model.
    */
-  private static constrainDelta( delta: number, range: Range, waterLevelProperty: NumberProperty ): number {
+  private static constrainDelta( delta: number, range: Range, waterLevelProperty: Property<number> ): number {
     const newWaterLevel = waterLevelProperty.value + delta;
     const constrainedWaterLevel = range.constrainValue( newWaterLevel );
     return constrainedWaterLevel - waterLevelProperty.value;
@@ -334,7 +334,7 @@ export default class IntroModel extends MeanShareAndBalanceModel {
    * @param waterLevel - The current waterLevel
    * @param oldWaterLevel - The previous waterLevel
    */
-  public changeWaterLevel( cup3DModel: WaterCup, adapterProperty: NumberProperty, waterLevel: number, oldWaterLevel: number ): void {
+  public changeWaterLevel( cup3DModel: WaterCup, adapterProperty: Property<number>, waterLevel: number, oldWaterLevel: number ): void {
 
     // During reset we only want to specify the exact values of the adapterProperty and waterLevelProperties.
     // We do not want to compensate with waterLevel deltas.
diff --git a/js/intro/model/WaterCup.ts b/js/intro/model/WaterCup.ts
index 081136ca..74716bd5 100644
--- a/js/intro/model/WaterCup.ts
+++ b/js/intro/model/WaterCup.ts
@@ -46,7 +46,7 @@ export type WaterCupModelOptions =
 export default class WaterCup extends PhetioObject {
 
   // Whether the cup is enabled in view and data calculations
-  public readonly isActiveProperty: BooleanProperty;
+  public readonly isActiveProperty: Property<boolean>;
 
   // The x and y positions for the cup in the view.
   public readonly position: Vector2;
diff --git a/js/intro/view/PredictMeanSlider.ts b/js/intro/view/PredictMeanSlider.ts
index 8c889ef6..444fe7b6 100644
--- a/js/intro/view/PredictMeanSlider.ts
+++ b/js/intro/view/PredictMeanSlider.ts
@@ -15,13 +15,11 @@ import meanShareAndBalance from '../../meanShareAndBalance.js';
 import Vector2Property from '../../../../dot/js/Vector2Property.js';
 import ModelViewTransform2 from '../../../../phetcommon/js/view/ModelViewTransform2.js';
 import Range from '../../../../dot/js/Range.js';
-import optionize from '../../../../phet-core/js/optionize.js';
-import { EmptySelfOptions } from '../../../../phet-core/js/optionize.js';
+import optionize, { EmptySelfOptions } from '../../../../phet-core/js/optionize.js';
 import MeanShareAndBalanceConstants from '../../common/MeanShareAndBalanceConstants.js';
 import AccessibleSlider, { AccessibleSliderOptions } from '../../../../sun/js/accessibility/AccessibleSlider.js';
 import Vector2 from '../../../../dot/js/Vector2.js';
 import ShadedSphereNode from '../../../../scenery-phet/js/ShadedSphereNode.js';
-import NumberProperty from '../../../../axon/js/NumberProperty.js';
 import WaterCup from '../model/WaterCup.js';
 import Property from '../../../../axon/js/Property.js';
 
@@ -34,7 +32,7 @@ export default class PredictMeanSlider extends AccessibleSlider( Node, 0 ) {
   private readonly predictMeanHandle: Circle;
   private readonly dragListener: DragListener;
 
-  public constructor( meanPredictionProperty: Property<number>, dragRange: Range, numberOfCupsProperty: NumberProperty,
+  public constructor( meanPredictionProperty: Property<number>, dragRange: Range, numberOfCupsProperty: Property<number>,
                       getActive2DCups: () => Array<WaterCup>, modelViewTransform: ModelViewTransform2, providedOptions: PredictMeanNodeOptions ) {
 
     const options = optionize<PredictMeanNodeOptions, SelfOptions, ParentOptions>()( {
diff --git a/js/intro/view/WaterCup3DNode.ts b/js/intro/view/WaterCup3DNode.ts
index 43a8aea1..53c4d3d2 100644
--- a/js/intro/view/WaterCup3DNode.ts
+++ b/js/intro/view/WaterCup3DNode.ts
@@ -29,12 +29,12 @@ type WaterCup3DNodeOptions = SelfOptions & StrictOmit<NodeOptions, 'y' | 'x' | '
 export default class WaterCup3DNode extends Node {
   private readonly waterLevelTriangle: WaterLevelTriangleNode;
   private readonly waterCup: WaterCup;
-  private readonly adapterProperty: NumberProperty;
+  private readonly adapterProperty: Property<number>;
   private readonly tickMarksVisibleProperty: Property<boolean>;
   private readonly showTickMarksLink: ( isShowingTickMarks: boolean ) => void;
 
   public constructor( tickMarksVisibleProperty: Property<boolean>,
-                      changeWaterLevel: ( cup3DModel: WaterCup, adapterProperty: NumberProperty, waterLevel: number, oldWaterLevel: number ) => void,
+                      changeWaterLevel: ( cup3DModel: WaterCup, adapterProperty: Property<number>, waterLevel: number, oldWaterLevel: number ) => void,
                       waterCup: WaterCup, modelViewTransform: ModelViewTransform2,
                       providedOptions?: WaterCup3DNodeOptions ) {
 
diff --git a/js/intro/view/WaterLevelTriangleNode.ts b/js/intro/view/WaterLevelTriangleNode.ts
index 9de268fb..2d8109a0 100644
--- a/js/intro/view/WaterLevelTriangleNode.ts
+++ b/js/intro/view/WaterLevelTriangleNode.ts
@@ -13,7 +13,6 @@ import StrictOmit from '../../../../phet-core/js/types/StrictOmit.js';
 import meanShareAndBalance from '../../meanShareAndBalance.js';
 import { Node, NodeOptions } from '../../../../scenery/js/imports.js';
 import optionize, { EmptySelfOptions } from '../../../../phet-core/js/optionize.js';
-import NumberProperty from '../../../../axon/js/NumberProperty.js';
 import VSlider from '../../../../sun/js/VSlider.js';
 import MeanShareAndBalanceConstants from '../../common/MeanShareAndBalanceConstants.js';
 import Range from '../../../../dot/js/Range.js';
@@ -29,7 +28,7 @@ export default class WaterLevelTriangleNode extends Node {
 
   //REVIEW why is waterLevelProperty not Property<number>, as in VSlider?
   //REVIEW why is enabledRangeProperty not IReadOnlyProperty<Range>, as in VSlider trait AccessibleValueHandler?
-  public constructor( waterLevelProperty: NumberProperty, enabledRangeProperty: Property<Range>, height: number,
+  public constructor( waterLevelProperty: Property<number>, enabledRangeProperty: Property<Range>, height: number,
                       providedOptions?: WaterLevelTriangleNodeOptions ) {
     const options = optionize<WaterLevelTriangleNodeOptions, SelfOptions, NodeOptions>()( {
         cursor: 'pointer'