When I use `su` to get root, and then I `cd ~`

I am not on the /root, when I `ls` it shows me a Desktop file and some hidden files like .bashrc, but nothing else.

```
root@debian:~# ls -a
.  ..  .adobe  .bash_history  .bashrc  .cache  .config  Desktop  .gnome2  .gnome2_private  .local  .macromedia  .mozilla  .profile  .vim  .viminfo

```

to go to the real /root I have to `cd /` from here.

I thought that there were no `../` from `/root`, so what is this `~` ?

edit 2 :

```
xxxx@debian:~$ ls
Desktop  Documents  Downloads  Music  Pictures  Public  Templates  Videos
xxxx@debian:~$ su
Password: 
root@debian:/home/xxxx# cd
root@debian:~# ls
Desktop
root@debian:~# pwd
/root
root@debian:~# cd /
root@debian:/# ls
bin  boot  dev  etc  home  initrd.img  lib  lib64  lost+found  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var  vmlinuz
root@debian:/# pwd
/

```