1-algorithms

#Lesson 1 - Algorithms

Before Class

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###Teacher Preparation

• A basic understanding of Scratch. Teacher should be familiar with motion, looks, control and event blocks.

Daily Objective

Students will be able to construct an algorithm in Scratch that moves a sprite about the stage.

Key Points

• An algorithm is a step-by-step procedure used to complete a task.
• Programs/robots do not assume anything.
• Scratch is a block-based programming language used to help beginning programmers.

Assessment

1. Informal assessment of student involvement during activity.
2. Upload first project to Scratch forum.

Vocabulary

• Algorithm
• Scratch
• Sprite
• Stage
• Script Area
• Block
• Loop

References

• http://scratch.mit.edu, use the "Create" tab

During Class

Do Now

1. Volunteer takes attendance. Procedure found here.
2. Tell students to form their own opinion on the following quote:

Opening

Ask student and volunteers to agree or disagree with the quote above. Use the prompts below to help facilitate conversation:

• How do a human and a computer/program work together?
• Do you ever team with a computer/program?

Introduction to New Material (“I Do”)

Ask students to log onto scratch.mit.edu. Students should set up a Scratch account using their school email. Once the account is created students will go to the CREATE tab. Once all accounts are set up, the teacher will provide a quick demo (~2 minutes) on how Scratch works.

Example How-to Demo: “These are blocks, they can be moved (click and dragged) into the script area (where the block become active) to move the sprite (Scratchy the cat) on the stage (The white area Scratchy lives in).”

Be sure to include that Scratch is a precursor to JavaScript. We will only be using Scratch for about 2 days.

Guided Practice (“We Do”)

“We have seen Scratchy move and turn in the stage. Now can you make scratchy move in a square that is 100 steps long when the user clicks the green flag?”
Note: You must use wait blocks or it will look like nothing happened.

Most students will end up with a script like this →

Independent Practice ("You Do")

After many students come up with the answer above, ask them to complete the same task but this time using less blocks. Hint: Use the repeat block.

Students should then create the program below, which uses fewer blocks by repeating the same action four times.

Ask class: “Why would a developer prefer to use the program with the repeat block over the first program you created?”

Closing/Homework

“We have made our first program today! Let’s reflect on what we have done. Would anyone like to share what they did that may have gone further than what the class has done?”

After Class

• Take a quick look at each Scratch project from today. Students who were not able to create the program should be asked to recreate the project, with teacher’s help, next class.
• Prepare for next lesson / hand off to next volunteer in rotation.