Bubbles not moving(floating) while scrolling page

var $bubble = $('.bubble');

function bubbles() {

// Settings

// Calculate a random number of bubbles based on our min/max
var bubbleCount = min_bubble_count + Math.floor(Math.random() * (max_bubble_count + 1));

// Create the bubbles
for (var i = 0; i < bubbleCount; i++) {
$bubble.append('<div class="bubble-container"><div class="bubble"></div></div>');
}

// Now randomise the various bubble elements
$bubble.find('.bubble-container').each(function(){

// Randomise the bubble positions (0 - 100%)
var pos_rand = Math.floor(Math.random() * 101);

// Randomise their size
var size_rand = min_bubble_size + Math.floor(Math.random() * (max_bubble_size + 1));

// Randomise the time they start rising (0-15s)
var delay_rand = Math.floor(Math.random() * 16);

// Randomise their speed (3-8s)
var speed_rand = 3 + Math.floor(Math.random() * 9);

// Random blur
var blur_rand = Math.floor(Math.random() * 3);

// Cache the this selector
var $this = $(this);

// Apply the new styles
$this.css({
'left' : pos_rand + '%',

'-webkit-animation-duration' : speed_rand + 's',
'-moz-animation-duration' : speed_rand + 's',
'-ms-animation-duration' : speed_rand + 's',
'animation-duration' : speed_rand + 's',

'-webkit-animation-delay' : delay_rand + 's',
'-moz-animation-delay' : delay_rand + 's',
'-ms-animation-delay' : delay_rand + 's',
'animation-delay' : delay_rand + 's',

'-webkit-filter' : 'blur(' + blur_rand + 'px)',
'-moz-filter' : 'blur(' + blur_rand + 'px)',
'-ms-filter' : 'blur(' + blur_rand + 'px)',
'filter' : 'blur(' + blur_rand + 'px)',
});

$this.children('.bubble').css({
'width' : size_rand + 'px',
'height' : size_rand + 'px'
});

});
}

// In case users value their laptop battery life
// Allow them to turn the bubbles off
$('.bubble-toggle').click(function(){
if($bubble.is(':empty')) {
bubble();
$bubble.show();
$(this).text('Bubbles Off');
} else {
$bubble.fadeOut(function(){
$(this).empty();
});
$(this).text('Bubble On');
}

return false;
});

bubble();