You can control the number of time slots that each hour on the Calendar will be split into.
1. Go to Tools | Organization and click on the organization name to open,
2. A new Organization Details window will open, scroll to the bottom of the page.
3. Go to Preferences | Calendar and click to open.
4. A new Calendar window will open | go to Duration and set the minimum duration | click Save.
5. Now go back to Organization Details and Save.
6. The number of minutes per row is now set to 10 minutes. Therefore each hour on the Calendar is split into six intervals of 10 minutes each.