# Lesson 10: Snowflakes with Anna and Elsa

## 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.

## Objectives

### Students will be able to:

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

## Preparation

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

## Vocabulary

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

# Teaching Guide

## Warm Up (15)

### 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)

### Course D 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)

### 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

#### 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 English Language Arts Standards

L - Language
• 3.L.6 - Acquire and use accurately grade-appropriate conversational, general academic, and domain-specific words and phrases, including those that signal spatial and temporal relationships (e.g., After dinner that night we went looking for them).
SL - Speaking & Listening
• 3.SL.1 - Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 3 topics and texts, building on others’ ideas and expressing their own clearly.
• 3.SL.1.b - Follow agreed-upon rules for discussions (e.g., gaining the floor in respectful ways, listening to others with care, speaking one at a time about the topics and texts under discussion).
• 3.SL.6 - Speak in complete sentences when appropriate to task and situation in order to provide requested detail or clarification.

#### Common Core Math Standards

G - Geometry
• 3.G.2 - Partition shapes into parts with equal areas. Express the area of each part as a unit fraction of the whole. For example, partition a shape into 4 parts with equal area, and describe the area of each part as 1/4 of the area of the shape.
MP - Math Practices
• MP.1 - Make sense of problems and persevere in solving them
• MP.2 - Reason abstractly and quantitatively
• 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
• 3.OA.4 - Determine the unknown whole number in a multiplication or division equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 × ? = 48, 5 = � ÷ 3, 6 × 6 = ?.

#### 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.
• 3-5-ETS1-2 - Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.