There's no error so why won't my part move..?

I am making a laser, I want it to move on the y axis. When I launch the game, The laser isn't moving and there's no error.. Any help?

Script:

local Vel = Instance.new("BodyVelocity")
Vel.MaxForce = Vector3.new(0, -1500, 0)
Vel.P = 1000
Vel.Velocity = Vector3.new(0, 1000, 0)
Vel.Parent = script.Parent.Laser

while true do
    wait(2.5)
    Vel.MaxForce = Vector3.new(0, 1500, 0)
    wait(2.5)
    Vel.MaxForce = Vector3.new(0, -1500, 0)
end