How Do I Make A Part Scale In One Direction?

The Current Script I'm Using :

game.Workspace.Apple.Touched:Connect(function()
    game.Workspace.Apple:Destroy()

 -- The Head
    game.Players.LocalPlayer.Character.HumanoidRootPart.Size = game.Players.LocalPlayer.Character.HumanoidRootPart.Size + Vector3.new(0,0,1)
    -- The Body
for i, v in pairs (game.Players.LocalPlayer.Head:GetChildren("Part")) do
        v.Size = v.Size + Vector3.new(1,1,1)
        v.Position = v.Position - Vector3.new(5,0,0)
    end
    game.Players.LocalPlayer.leaderstats.Size.Value = game.Players.LocalPlayer.leaderstats.Size.Value + 1
end)