While we expect that ZTF will produce data valuable for a wide range of scientific inquiry, we specify the following science topics as those which may drive requirements on the ZTF Observing and Data Systems:

1. 1.

   Discovery of Fast, Young, and Rare Transients (Section \ref{sec:transients})

2. 2.

   Characterizing Low-\(z\) SNe Ia (Section \ref{sec:Ia})

3. 3.

   Searches for Electromagnetic Counterparts to Gravitational Wave Sources (Section \ref{sec:EMGW})

4. 4.

   Characterization of Variable Sources (Section \ref{sec:variables})

5. 5.

   Asteroid Discovery (Section \ref{sec:asteroids})

Specific goals from other science programs may drive specific observing cadences but shall not levy requirements on the ZTF Observing and Data Systems.

In subsequent sections we describe the major science programs and the requirements they place on ZTF.