Kennen und Wissen

The problem is that there are two words in German for the word "know". To avoid missunderstanding it's necessary to know the difference between "wissen" and "kennen".

1.) "Kennen" is used to express that we are familar with a person or a place.

examples:

• Ich kenne Nelson. Ich habe ihn letzte Woche getroffen. (I know Nelson. I met him last week.)
• Wer bist du? Ich kenne dich nicht. (Who are you? I don't know you.)
• Kennst du die Stadt Nideggen? (Do you know the city Nideggen?)

2.) "Wissen" is used to express that you know a fact. You've got knowledge about something.

examples:

• Ich weiß, wann du geboren bist. (I know when you was born.)
• Er weiß die Antwort nicht. (He doesn't know the answer.)
• Weißt du, wie spät es ist?. (Do you know what's the time?)

Unfortunately, these two easy rules don't explain all situations. Therefore, you should consider these additional rules as well:

3.) "Kennen" is always used if you can answer a question just by one noun or pronoun.

examples:

• Kennst du das Lied? (Do you know the song?)
• Ja, ich kenne das Lied. / Ja, ich kenne es. (Yes, I know the song. / Yes, I know it.)

• Kennst du den Unterschied zwischen "wissen" und "kennen"? (Do you know the difference between "wissen" and "kennen"?)
• Ja, ich kenne den Unterschied. / Ja, ich kenne ihn. (Yes, I know the difference. / Yes, I know it.)

4.) "Wissen" is always used if your answer requires a whole phrase, not just one word. The answer "Ich weiß es." or "Ich weiß es nicht." doesn't count. Answer the question in another way and you know if it has to be "kennen" or "wissen".

examples:

• Weißt du, wo ich wohne? (Do you know where I live?)
• Ja, ich weiß, wo du wohnst. (Yes, I know where you live.)

• Wissen Sie, wann Zug kommt? (Do you know when the train arrives?)
• Nein, ich weiß nicht, wann er kommt. (No, I don't know when it arrives.)

A last hint: A sentence with "wissen" is usually followed by a subordinate clause which starts with "wie, wann, wo, wer, warum ...".

conjugation of "kennen" and "wissen"

We spoke already about the conjugation of "kennen" and "wissen".
I'd like to refresh it, however.

Infinitiv	ich	du	er / sie / es	wir	ihr	sie / Sie
kennen	kenne	kennst	kennt	kennen	kennt	kennen
wissen	weiß	weißt	weiß	wissen	wisst	wissen