# Lesson 9: Nested Loops with Frozen

## Overview

Now that students know how to layer their loops, they can create so many beautiful things. This lesson will take students through a series of exercises to help them create their own portfolio-ready images using Anna and Elsa's excellent ice-skating skills!

## Purpose

In this series, students will get practice nesting loops while creating images that they will be excited to share.

Beginning with a handful of instructions, students will make their own decisions when it comes to creating designs for repetition. They will then spin those around a variety of ways to end up with a work of art that is truly unique.

## Agenda

### Warm Up (15 min)

### Main Activity (30 min)

### Wrap Up (15 min)

### View on Code Studio

## Objectives

### Students will be able to:

- Describe when a loop, nested loop, or no loop is needed.
- Recognize the difference between using a loop and a nested loop.
- Break apart code into the largest repeatable sequences using both loops and nested loops.

## Preparation

- Play through the Course E Online Puzzles 2018 - Website corresponding to this lesson to find and potential problem areas for your class.
- Review CS Fundamentals Main Activity Tips - Lesson Recommendations.
- Make sure every student has a Think Spot Journal - Reflection Journal.

## Links

**Heads Up!** Please make a copy of any documents you plan to share with students.

### For the Teachers

- Course E Online Puzzles 2018 - Website
- CS Fundamentals Main Activity Tips - Lesson Recommendations

### For the Students

- Think Spot Journal - Reflection Journal

## Vocabulary

**Loop**- The action of doing something over and over again.**Repeat**- To do something again.

## Support

### Report a Bug

# Teaching Guide

## Warm Up (15 min)

### Introduction

Ask the class to discuss the last set of puzzles.

- What did they like/dislike?
- Which puzzles were hard? Why?
- Which puzzles were easy? Why?
- If you were to teach nested loops to a friend, what would you say to help them understand?

If there's time, give an introduction to the main characters of today's puzzles, Anna and Elsa from Frozen. Give the class the sister's back story if the class doesn't already know. To build excitement, tell the class they will be using nested loops to make some fantastic drawings with Anna and Elsa's ice skates!

## Main Activity (30 min)

### Course E Online Puzzles 2018 - Website

This set of puzzles is set up as a progression. This means every puzzle builds a foundation for the next puzzle. Students will enjoy making more and more interesting designs by making small and simple changes to code they have already written.

## Wrap Up (15 min)

### Journaling

Having students write about what they learned, why it’s useful, and how they feel about it can help solidify any knowledge they obtained today and build a review sheet for them to look to in the future.

#### Journal Prompts:

- What was today’s lesson about?
- How did you feel during today’s lesson?
- When do you use a loop? When do you use a nested loop?
- Thought exercise: Can you make everything a nested loop can with just a normal loop? Can you draw out an example?
- Answer: Yes, you can, but it is a lot more difficult. Nested loops make programs simpler.

## Standards Alignment

#### View full course alignment

#### CSTA K-12 Computer Science Standards (2017)

**AP** - Algorithms & Programming

**1B-AP-11**- Decompose (break down) problems into smaller, manageable subproblems to facilitate the program development process.**1B-AP-13**- Use an iterative process to plan the development of a program by including others' perspectives and considering user preferences.

## Cross-curricular Opportunities

This list represents opportunities in this lesson to support standards in other content areas.

#### Common Core Math Standards

**MD** - Measurement And Data

**4.MD.5**- Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and understand concepts of angle measurement:**4.MD.5.a**- An angle is measured with reference to a circle with its center at the common endpoint of the rays, by considering the fraction of the circular arc between the points where the two rays intersect the circle. An angle that turns through 1/360 of a circle i**4.MD.5.b**- An angle that turns through n one-degree angles is said to have an angle measure of n degrees.

**MP** - Math Practices

**MP.1**- Make sense of problems and persevere in solving them**MP.2**- Reason abstractly and quantitatively**MP.3**- Construct viable arguments and critique the reasoning of others**MP.4**- Model with mathematics**MP.5**- Use appropriate tools strategically**MP.6**- Attend to precision**MP.7**- Look for and make use of structure**MP.8**- Look for and express regularity in repeated reasoning

**OA** - Operations And Algebraic Thinking

**4.OA.1**- Interpret a multiplication equation as a comparison, e.g., interpret 35 = 5 × 7 as a statement that 35 is 5 times as many as 7 and 7 times as many as 5. Represent verbal statements of multiplicative comparisons as multiplication equations.**4.OA.5**- Generate a number or shape pattern that follows a given rule. Identify apparent features of the pattern that were not explicit in the rule itself. For example, given the rule “Add 3” and the starting number 1, generate terms in the resulting sequence and

#### Next Generation Science Standards

**ETS** - Engineering in the Sciences

**ETS1** - Engineering Design

**3-5-ETS1-1**- Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.