TimeStory lets you zoom in and out on your document, to get a better view of things or to help present it on screen to others. You can zoom in any of the following ways:

100% is the default and starting zoom level. 25% is the minimum size, and 400% is the maximum size. Zooming affects all document contents equally: event graphics, font sizes, spacing, etc.

If you want to leave font sizes, shapes, etc. unchanged, but just view more or less detail in your timeline, you may want to just adjust the time scale.