Cronulla High School runs on a 10-day cycle (Week A and Week B) with each day broken into 6 x 50 minute periods. This system makes for less daily movement around the school and contributes to a quiet and calm environment. It also keeps bell times sensible, as you will see from the table below. 
BELL TIMES 
MONDAY - WEDNESDAY - FRIDAY
Assembly: 8.45am - 8.55am
Reading: 8.55am - 9.10am
Period 1: 9.10am - 10.00am
Period 2: 10.00am - 10.50am
Recess: 10.50am - 11.10am
Period 3: 11.10am - 12.00pm
Period 4: 12.00pm - 12.50pm
Lunch 1: 12.50pm - 1.10pm
Lunch 2: 1.10pm - 1.30pm
Period 5: 1.30pm - 2.20pm
Period 6: 2.20pm - 3.10pm 

TUESDAY
As above, but excluding Period 6, Tuesday i.e. five periods only, concluding at 2.20pm for students. 

THURSDAY (Sports afternoon)
Assembly 8.45am - 8.55am
Period 1: 8.55am - 9.40am
Period 2: 9.40am - 10.25am
Recess: 10.25am - 10.45am
Period 3: 10.45am - 11.30am
Period 4: 11.30am - 12.15pm
Sports Assembly: 12.15pm - 12.30pm
Lunch 1: 12.30pm - 12.50pm
Lunch 2: 12.50pm - 1.10pm
Sport: 1.10pm - 2.30pm