Context of the Standard

At school and at home, students engage in step-by-step activities on a routine basis.  These may include such activities as brushing their teeth or preparing to leave school at the end of the school day.  When students document these step-by-step instructions they are creating algorithms.  Sometimes there are repeating steps in a task, and students can create a loop in their algorithm to indicate that repeating pattern. Algorithms can be created with or without computers. In first grade the students are introduced to the use of loops, in second grade this understanding expands to include repeating patterns and growing patterns.  

In second grade, the construction of loops becomes more complex as students use a wide variety of patterns to include repeating and growing patterns.  In a repeating pattern the units of the pattern repeat and remain the same.  In a growing pattern, an addition is added to the pattern causing the pattern to change every time it repeats.  Growing patterns involve a progression from step to step which make them more difficult for students than repeating patterns.

Repeating and growing patterns are foundational in mathematics in the development of algebraic reasoning and in computer science in developing computational thinking.  

Sample numeric patterns include:

–      6, 9, 12, 15, 18,....(growing pattern);

–      1, 2, 4, 7, 11, 16,….(growing pattern);

–      20, 18, 16, 14,…..(growing pattern); and

   1, 3, 5, 1, 3, 5, 1, 3, 5,.....(repeating pattern).

In second grade, students are also expected to identify events.   In computer science, an event is an action or occurrence detected by a program. Events can be user actions, such as clicking a mouse button or pressing a key, or system occurrences, such as a timer or low battery.

Essential Skills

Essential Questions

Essential Vocabulary

Students should demonstrate these skills:

• Describe the steps taken to accomplish an activity using both sequences and loops.
• Identify a section of repeated actions to replace with a loop.
• Given a sequence of steps that include a loop, predict the next step in the sequence.
• Given a sequence of steps to accomplish a daily task, give a possible event that triggers these steps.
• Compare and contrast a repeating pattern and a growing pattern.

Students should investigate these concepts:

• What are examples of tasks where a loop would be appropriate?
• What are examples of events in a plugged or an unplugged activity?
• What is the difference between a repeating and a growing pattern?
• How can repeating and growing patterns be represented in a sequence?

Students should be introduced to these concepts:

• Loop
• Event