diff --git a/src/models/science/TestTube.ts b/src/models/science/TestTube.ts
index d5c8010..e6c4916 100644
--- a/src/models/science/TestTube.ts
+++ b/src/models/science/TestTube.ts
@@ -16,6 +16,7 @@ class TestTube extends Group {
       metalness: 0.1,
       reflectivity: 0.8,
       transmission: 0.9, // For glass effect
+      depthWrite: false,
       side: DoubleSide,
     });
 
diff --git a/src/models/science/TestTubeRack.ts b/src/models/science/TestTubeRack.ts
index 3483f97..9a4e114 100644
--- a/src/models/science/TestTubeRack.ts
+++ b/src/models/science/TestTubeRack.ts
@@ -23,6 +23,7 @@ class TestTubeRack extends Group {
       opacity: 0.4,
       roughness: 0.1,
       metalness: 0.5,
+      depthWrite: false,
       side: DoubleSide,
     });