In Pairs help?

So what I'm trying to do is make the Pair transparent, then nontransparent after 1 second. Apparently It's only making that loop to the 1st Brick, not the 2nd Brick.

button=script.Parent
siren=game.Workspace.siren:GetChildren()

function onClick()
    for i=1,10 do
        for o,p in pairs(siren) do
        siren[o].Transparency=1
        end
                wait(1)
        for o,p in pairs(siren) do
        siren[o].Transparency=0
        print(i)
end end end

button.ClickDetector.MouseClick:connect(onClick)

What I'm trying to figure out is how to get the 2nd Brick to do what the 1st Brick is doing > (which In Pairs should do automatically....) Help would be appreciated!