Python Functions 🐍 | 1.3 Karel Can't Turn Right

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Python CodeHS 1.3 Nearpod Lesson

Python Functions
Your Code Superpowers
Unlocked!

Today YOU become a Python Software Engineer. Build real functions, solve Karel problems, and write code like the pros at Google and Netflix.

🎯 What Are Functions?

Think of a Function as Your Personal Robot Assistant

You teach it how to do a specific task once, and then you can ask it to do that task whenever you want — just by saying its name!

        
        Python
      
1def turn_right():
2    turn_left()
3    turn_left()
4    turn_left()
5
6# Now you can use it!
7turn_right()  # Karel turns right!

📝 Python Function Writing Format — Line by Line:

Line 1: Start with the def keyword
Line 1: Add your function name using lowercase_with_underscores
Line 1: Add parentheses () after the name
Line 1: End with a colon : — never forget this!
Lines 2+: Indent 4 spaces (or 1 tab) for every command in the body
Body: Write all commands that should run when you call the function

🍕 Real-World Example

Making Pizza

Would you really type all these steps every single time someone orders pizza? What if there are 1,000 orders?

❌ Without Functions

Every time you want pizza, you repeat:

Roll dough
Add sauce
Add cheese
Add toppings
Bake for 15 minutes
...repeated 1,000× 😭

→

✅ With a Function

Create make_pizza() once, then call it!

            
            Python
          
1def make_pizza():
2    roll_dough()
3    add_sauce()
4    add_cheese()
5    bake(15)
6
7# 1,000 orders = 1,000 calls:
8make_pizza()  ✓

🛠️ Function Anatomy

Dissecting a Python Function — Line by Line

Every part has a job. Learn each one and you'll never write a broken function again.

        
        Python
      
1def function_name():  ← Function definition
2    # Function body        ← These are the steps
3    command1()
4    command2()
5    command3()
6
7function_name()           ← Calling the function

🔑

def

Stands for "define." Tells Python you are creating a new function.

📛

snake_case Name

Lowercase with underscores. Describes exactly what the function does.

🔵

Colon (:)

Required at the end of line 1. If you forget it, Python throws an error!

➡️

Indentation

4 spaces or 1 tab. Python requires this to know what's inside the function.

📱 Real-World: Your Morning Routine

One Call. Five Tasks Done.

Instead of doing 5 things every morning manually, you just call ONE function!

        
        Python
      
1def get_ready_for_school():
2    wake_up()
3    brush_teeth()
4    get_dressed()
5    eat_breakfast()
6    pack_backpack()
7
8# Every morning you just run:
9get_ready_for_school()

⚡ Power of Functions: Instead of calling 5 separate commands every morning, you just call get_ready_for_school() once — and all 5 steps run automatically!

⚙️ Guided Practice — 5-Step Engineering Process

Solving the Karel Problem

Real engineers follow a process. You will too — right now!

Identify the Problem

Karel can't turn right. We need this capability to solve more complex mazes and towers!

Design a Solution

How can we simulate a right turn using only turn_left()? Think about a compass — 3 left turns = 1 right turn!

Implement — Write the Smart Shortcut

              
              Python
            
1def turn_right():
2    turn_left()
3    turn_left()
4    turn_left()

Test the Solution 🏃

Stand up! Turn left three times together. Did you end up facing the same direction as one right turn? Yes — it works! Our engineering solution is verified.

Use It Efficiently

Apply turn_right() in CodeHS 1.3.3: Tower and Turn Right. One call replaces three turn_left() commands every time!

💪 Why Functions Are Awesome

4 Superpowers Every Engineer Uses

This is why professional engineers at Google, Netflix, and your favorite game studios love functions!

🔄

No More Repetition

Write once, use everywhere! This is the DRY Principle — Don't Repeat Yourself.

🧹

Cleaner Code

Your code looks organized and professional — like a tidy room vs. a messy one!

🐛

Easier Debugging

If something breaks, you only fix it in one place — not 100 times!

🤝

Better Teamwork

Other programmers can easily understand and use your functions without knowing how they work inside.

🌟 Cool Real-World Function Examples

Functions Power Everything You Use

Every time you respawn, post a photo, start a movie, or ride in a self-driving car — a function is running.

🎮 Gaming

Python
1def respawn_player():
2    restore_health(100)
3    move_to_checkpoint()
4    reset_inventory()
5    play_respawn_sound()

When called: all 4 commands run automatically!

🏠 Smart Home

Python
1def movie_night():
  dim_lights()
  turn_on_tv()
  set_volume(15)
  close_curtains()
  order_popcorn()

One command sets up your whole movie experience!

🚗 Self-Driving Car

Python
1def park_car():
  check_spot()
  signal_turn()
  slow_down()
  turn_wheel()
  reverse_slowly()
  stop()

Complex parking broken into simple steps!

🎪 Interactive Function Demo

Watch a Function Execute Live!

Click the button to see make_sandwich() run step by step.

          
          Python
        
1def make_sandwich():
2    get_bread()
3    add_peanut_butter()
4    add_jelly()
5    put_top_slice()
6    cut_diagonally()
7
8make_sandwich()  ← Click Run!

Output will appear here when you click Run...

💻 CodeHS Activities

Apply Your Superpowers!

Open CodeHS and complete both challenges using your new turn_right() function.

🗼

Activity 4 — 1.3.3: Tower and Turn Right Individual

Apply turn_right() to build a tower and navigate Karel. Check: correct def, colon, and indentation!

Open CodeHS →

🚒

Activity 5 — 1.3.4: Fireman Karel Collaboration

Work with a partner! Solve Fireman Karel using custom functions. Look for repeated patterns — can you turn ANY of them into a function?

Open CodeHS →

👀 Teacher Note: Circulate and check for correct function syntax, proper indentation, and understanding of when to call the function.

🎯 Kahoot-Style Function Quiz

Test Your Function Knowledge!

5 questions — how many can you ace? 🏆

🎪 Closure — Exit Ticket

Function Creator Challenge

Demonstrate mastery by creating your OWN custom Karel function!

Create Your Function

Ideas: climb_stairs(), build_tower(), collect_all_balls()

Your Custom Function Code: Why is your function useful? (1–2 sentences):

🎉 Great work, Engineer! Screenshot this and submit to Canvas.

✅

Success Criteria

Function has correct syntax: def, colon, indentation
Function solves a specific problem
You can explain its purpose in your own words

🗣️

Final Question

"What did you learn today about thinking like a software engineer?"

Be ready to share with the class!

🎉 Lesson Complete!

You're a Python Engineer Now!

You learned the DRY principle, function syntax, and applied it in CodeHS — just like real engineers do!

✍️

Writing

Exit ticket, Canvas responses, function comments

🔍

Inquiry

Guided questions, problem-solving Karel

🤝

Collaboration

Fireman Karel partner work, physical turn-left test

📐

Organization

5-step engineering process, structured code

🏆 Bonus Challenge: Find another repeated pattern in your CodeHS code and turn it into a function. Show your teacher for extra credit!

Python FunctionsYour Code SuperpowersUnlocked!