Lesson 22: For Loops with Bee
Overview
Featuring Bee, this lesson focuses on for loops and using an incrementing variable to solve more complicated puzzles. Students will begin by reviewing loops from previous lessons, then they'll walk through an introduction to for loops so they can more effectively solve complicated problems.
Purpose
Today's concept, for loops, are a very important topic in computer science. Not only are they widely used, the process of learning for loops enhances the learning of other important concepts (such as variables and parameters.) Students will have plenty of practice critically thinking through problems by determining the starting, ending, and stepping values for each for loop. This concept uses plenty of math as well, so feel free to pair it with a math lesson for an even deeper learning experience.
Agenda
Bridging Activity - For Loops (15 min)
Main Activity (30 min)
Wrap Up (15 min)
View on Code Studio
Objectives
Students will be able to:
- Determine starting value, stopping value, and stepping value for a `for` loop.
- Recognize when to use a `for` loop and when to use other loops such as `repeat` and `while` loops.
Preparation
- Play through the lesson to find any potential problem areas for your class.
- Make sure every student has a journal.
Links
Heads Up! Please make a copy of any documents you plan to share with students.
For the Students
- Think Spot Journal - Reflection Journal
Vocabulary
- For Loop - Loops that have a predetermined beginning, end, and increment (step interval).
Support
Report a Bug
Teaching Guide
Bridging Activity - For Loops (15 min)
Previewing Online Puzzles as a Class
Display a puzzle from the lesson. We recommend puzzle #5 because it displays a potential solution and asks the user to evaluate it.
Using a number line, mark the start and ending values of the given for loop (if you aren't using puzzle #5, you will need to come up with a potential solution first). With the class's help, circle the values between the start and end that the for loop will touch. If you are working on puzzle #5, ask the class what they think the answer is to the question, given what they found with the number line.
Main Activity (30 min)
Online Puzzles
Some students may have a hard time differentiating between repeat loops and for loops. We recommend having scratch paper out for students to make guesses on values like the start, stop, and step. Implementing pair programming amongst the class might also be helpful for your students.
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:
Student Instructions
Student Instructions
Write the code to help the bee collect all of the nectar.
You will need lots of blocks for this challenge, but we'll learn an easier way in the next puzzle.
Student Instructions
In this lesson...
Today you'll be learning about a new kind of repeat loop. Here is a preview of the block you'll be using:
Fortunately, this new loop will make solving puzzles like this really easy!
Student Instructions
Ah! The use of for loops makes this puzzle a lot easier!
Read the code below. What will happen when you click "Run"?
The bee will move forward and collect all of the nectar from every flower.
The bee will move forward and collect all of the nectar from every flower, except for one.
The bee will move forward and collect one nectar from each flower.
I don't know.
Student Instructions
Student Instructions
You can also use a for loop to count down.
Try gathering this nectar by counting down from 5 to 1 by 1.
Student Instructions
The last number in your for loop is called the "increment". Each time the loop is run, the counter variable changes by the value of the increment.
Try collecting these flowers using an increment of 2.
Student Instructions
You've got this!
What should your increment be to collect 3, 6, 9, 12, 15 nectar?
Student Instructions
Student Instructions
Now, let's combine the counter variable with a math block!
How can you use the counter variable to navigate this garden with the fewest number of blocks possible?
Student Instructions
Challenge: Take what you've learned about for loops and try to solve this problem.
Remember: You may have to run through solutions multiple times before you figure out all of the steps.
Student Instructions
If your loop is counting down, the increment is subtracted from your counter variable each time through.
What should your increment be to collect 15, then 12, then 9, 6, 3 nectar?
Student Instructions
You just learned "for loops"!
For loops are loops where you set the start, stop, and step values.
This new kind of repeat loop gives you more control over when you loop starts, when it ends, and what your loop should increase by every time it runs.
More control means you can solve puzzles a lot faster!
Vocab to Know
For loop - For loops are loops that have a predetermined beginning, end, and increment (step interval)
Student Instructions
You can use this for loop to collect all of the nectar. Un-bee-lievable!
There are a few actions that you will want to repeat 'counter' times.
Student Instructions
Solve this puzzle with the fewest number of blocks possible.
Standards Alignment
View full course alignment
CSTA K-12 Computer Science Standards (2017)
AP - Algorithms & Programming
- 1B-AP-09 - Create programs that use variables to store and modify data.
- 1B-AP-11 - Decompose (break down) problems into smaller, manageable subproblems to facilitate the program development process.