student_tasks.md

Week 13 – Student Tasks: Moving Dot (Pygame Zero)

FIRST: Installation Check

Before starting, make sure Pygame Zero is installed:

1. Open week13.py in Thonny
2. Press F5 to run
3. You should see a white dot moving and bouncing

If it doesn't work: Ask teacher for help with installation!

Task A: Run and observe

1. Run the program
2. Watch the dot move and bounce
3. Notice: It bounces automatically off left and right edges
4. Try to count: How many times does it bounce in 10 seconds?

Task B: Make modifications

1. Change speed

   • Find: vx = 3
   • Try: vx = 5 (faster)
   • Try: vx = 1 (slower)
   • Try: vx = -3 (starts moving left!)

2. Change dot appearance

   • Find: screen.draw.filled_circle((x, y), 10, "white")
   • Change 10 to 20 (bigger dot)
   • Change "white" to "red" or "yellow"

3. Change window size

   • Find: WIDTH = 600 and HEIGHT = 400
   • Try: WIDTH = 800 and HEIGHT = 600 (bigger window)

4. See the trail effect

   • Find: screen.clear()
   • Comment it out: # screen.clear()
   • Run again - the dot leaves a trail!
   • Uncomment it to go back to normal

Task C: Add vertical bouncing

Make the dot bounce up and down too!

1. Add vertical velocity:

   vx = 3
   vy = 2  # Add this line

2. Update y position in update():

   def update():
       global x, vx, y, vy  # Add y and vy
       x += vx
       y += vy  # Add this line
       
       if x < 10 or x > WIDTH - 10:
           vx = -vx
       
       if y < 10 or y > HEIGHT - 10:  # Add vertical bounce
           vy = -vy

Now it bounces in all directions!

Task D: Creative challenges

1. Color-changing dot

   # At top, add:
   colors = ["red", "blue", "green", "yellow", "purple"]
   color_index = 0
   
   # In update(), when bouncing:
   if x < 10 or x > WIDTH - 10:
       vx = -vx
       color_index = (color_index + 1) % len(colors)
   
   # In draw():
   screen.draw.filled_circle((x, y), 10, colors[color_index])

2. Two dots

   # Variables
   x1 = 100
   vx1 = 3
   x2 = 500
   vx2 = -3
   
   # Update both
   def update():
       global x1, vx1, x2, vx2
       x1 += vx1
       x2 += vx2
       if x1 < 10 or x1 > WIDTH - 10:
           vx1 = -vx1
       if x2 < 10 or x2 > WIDTH - 10:
           vx2 = -vx2
   
   # Draw both
   def draw():
       screen.clear()
       screen.draw.filled_circle((x1, HEIGHT//2), 10, "white")
       screen.draw.filled_circle((x2, HEIGHT//2), 10, "red")

3. Accelerating dot

   # Make it speed up over time
   def update():
       global x, vx
       x += vx
       if x < 10 or x > WIDTH - 10:
           vx = -vx * 1.1  # Increase speed by 10% each bounce

Success checklist

• I can run Pygame Zero programs
• I understand update() changes things
• I understand draw() shows things
• I can modify speed and colors
• I added vertical bouncing (Task C)