If a Node’s parent is scaled then the child node will move faster. Otherwise you can increase the moving_speed by the scale in your script func _process(delta: float) -> void: position.y -= moving_speed * delta * scale.y # or scale.x with uniform scaling

Thank you for your response! I tried to do it like you said: func _process(delta: float) → void: position.y -= moving_speed * delta * scale.y # or scale.x with uniform scaling but the bubbles still move at different speeds…