Help with i,v in pairs?

****What I am trying to do is, when I click on a button then all parts in the "PhoneOn" folder get transparent.

Button = script.Parent
Button.ClickDetector.MouseClick:connect(function()

    local Screen = script.Parent.Parent.Screen

    for i,v in pairs {Screen} do
        if v.Material == Enum.Material.SmoothPlastic then
            v.Material = Enum.Material.Neon
        else
            v.Material = Enum.Material.SmoothPlastic
        end
    end
    --Mostly worrying about the script below.
    local PhoneOn = script.Parent.Parent.Parent.PhoneOn --PhoneOn is the name of the folder with parts in it.

    for i,v in pairs (PhoneOn:GetChildren()) do
        if v:IsA("Part") then
            v.Transparency = 1
        end
    end
end)