copying and enter value onto another worksheet

Hi there,

I was wondering if the following is achievable in excel via cell functions/formulas or VBA programming.

Say I enter a value in cell A1, say 'tiger' in SHEET1.
After I press enter this value gets copied to a cell in SHEET2 say in A1, 'tiger'.
then I enter another value in cell A1 of say, 'lion' and press enter (basically overwriting the value in cell A1)
After I press enter the value get copied to a cell in SHEET2 at A2, 'lion'.

So basically whatever I put in A1 cell of Sheet1, it gets copied to SHEET2 A Column one by one.

Is this doable?
how can I start?
any help would be appreciated. Thanks in advance.
SN