Intro CS – Loops & Creating Shapes Lesson Plan 4

Loops, Creating shapes, Goals Review last week: sprite movement, pens (haven’t learned yet) Introduce Algorithm - a list of well defined instructions to solve a class of problems Examples: Drawing your name using Scratch Multiplying two numbers Show square example (no looping) Show square example (repeat loop) Show squares/checkerboard example (nested loops) Show input to collect number of sides, side length, angle to turn Give exercises for in class practice (show shapes on slides, students try to create those shapes) Students should come out of this lesson understanding the coordinate system, spatial properties, and how to draw using pen LP ideas from: http://www.cs.uni-potsdam.de/~romeike/UEWettbewerb/index-english.htm

Agenda Review what we learned in the last lesson – how to create a short animation film – what were some interesting things you noticed? Topics today, we will be stepping back and learning the fundamentals of how to draw in Scratch: Coordinate system How to draw lines in Scratch How to draw a square How to draw a circle How to use loops to draw images many times LP ideas from: http://math2033.uark.edu/wiki/index.php/Scratch_Programming

Drawing Using Loops Lesson Plan 4 Today we will be learning how to draw shapes and pictures in Scratch. Let’s review the last lecture and daily project. What were some things you found to be difficult? Some interesting things? Did anyone have difficulty with the placement of the sprite on the screen? Anyone notice the x-axis and y-axis and go to x/y axis block?

Coordinate system Coordinate system: uses numbers or coordinates to uniquely determine the position of a point. 2 1 Questions to ask: Show of hands how many of you know about the coordinate system? How many of the students are familiar with coordinate system? Will we have to review? Which one is the x-axis, y-axis? Four quadrants: 1, 2, 3, 4 in C shape Examples: where do you think the points are? (0, 0) origin (100, 100) (-50, 25) (50, -25) (-50, -50) Ask students for numbers and have them tell you where to draw the point 3 4

Drawing Lines Pretend I’m a sprite, what would you tell me to do step by step to draw a line? Questions to ask: Pretend I’m a robot, what would you tell me to do in order to draw a line? Pick up a pen Put the pen down on the paper Pick a direction Go forward for x number of steps Pick the pen back up How do you think we could change color and size of the line?

Drawing Squares How would I draw a square? Questions to ask: Again pick up pen Put the pen down on the paper Pick a direction Go straight until you move x number of steps Turn 90 degrees and do all over again 3 more times What’s something you noticed about this code? What are we repeating many times? How can we simplify the code so it becomes shorter and less repetitive? We want the code to do the work for us, we shouldn’t have to manually do everything.

Drawing circles How could I draw a circle? How do you think we would draw a circle? Think about how many degrees there are in a circle and how many times I would have to turn? How to change the color and size of the circle? How to increase the radius of the circle? Change the number of steps you move.

Using loops to draw How could we draw a square 4 times? One in each quadrant If we wanted to draw a square 4 times how could we do this? One in each quadrant.

Example Demo Let’s look at an example of using a sprite to make a square and circle Draw Square and Circle Turtle, walking to do a circle, forward and turning

Daily project By the end of class, each student should create a project that shows a drawing they have done of their initials or other drawing and repeat it in each quadrant of the coordinate system. Worth 13 points total Grade Breakdown – Must Include Points 1) Use pen up/down 1 point 2) Drawing of student’s initials or another drawing 3 points 3) Repeat the drawing in each quadrant 4 points; 1 for each quadrant 4) Change color of the pen 5) Change size of pen stroke 6) Cool shape in middle of screen (using repeat loops)

Surveys 1) http://www.surveymonkey.com/s/TEALS 2) Class Survey Sign in to Connect Search for Mr. Parker Click Mr. Parker’s Web Site Click Info/Posts tab Click “Please answer a few questions about yourself” Fill out the survey