What's difference between Lambda Calculus and Lisp/Scheme?

[chris at seberino.org]

Anyone know what the difference and similarities are between
Lambda Calculus and Lisp/Scheme??

Why couldn't we program in Lambda Calculus?  Why did we need to invent/develop
Lisp instead?

If I had to guess I'd say Lambda Calculus is probably easier to do math proofs
in and Lisp is probably easier to do program proofs in.

Chris