How to I make blocks that float down slowly (READ FULL QUESTION)?

How to I make blocks that float down slowly and then when they hit an object the slowly fade away and then regen at the top to repeat the cycle?

What I mean by this the block starts in mid air and slowly floats to the bottom (baseplate) when he hits an object (like a part or a player) its slowly disappears (slowly fades away) Until you cant see it anymore. but ti actually spawns back at the top to fall down once more.

Dont know what I mean? look at this game!

http://www.roblox.com/The-fabric-of-reality-place?id=110000824

Please help THANKS!

Put it in any regular brick, it must be unanchored for it to work.

Edit; This script is not for sale nor for redistribution through monetary value, this script is public domain under privilege by owner, M39a9am3R.

--Script by M39a9am3R
script.Parent.FormFactor = 2
script.Parent.Size = Vector3.new(6,6,6)
script.Parent.BrickColor = BrickColor.Black()
locationtoremember = script.Parent.Position
bodyf = Instance.new("BodyForce")
bodyf.force = Vector3.new(0,math.random(37500,41000),0)
bodyf.Parent = script.Parent
sb=Instance.new("SelectionBox")
sb.Parent = script.Parent
sb.Adornee = script.Parent
sb.Color = BrickColor.Random()
light = Instance.new("PointLight")
light.Parent = script.Parent
light.Color = script.Parent.SelectionBox.Color.Color
light.Range = 10
script.Parent.Rotation = Vector3.new(math.random(-5,5),math.random(-5,5),math.random(-5,5))
script.Parent.Touched:connect(function(part)
local disolving = false
if disolving == false then
disolving = true
local i=0
while i ~= 100 do
i=i+1
sb.Transparency = i/100
script.Parent.Transparency = i/100
wait()
end
script.Parent.Position = locationtoremember
sb.Transparency = 0
script.Parent.Rotation = Vector3.new(math.random(-5,5),math.random(-5,5),math.random(-5,5))
disolving = false
end
end)