Translation:Your coffee is cold, whereas my water is hot.
Am I the only one who finds it odd that the preferred translations for 'tandis que' are 'whereas' and 'whilst'? When was the last time you heard someone say 'whilst' in this situation? I might use 'whereas' in a formal setting or in writing, but I don't think I would use it to my chum in a coffee shop. How about 'while' maybe? :)