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Scratch Lessons: Rock Paper Scissors, Part 1

1. Open up Photo Booth. Take 4 picturs of your hands: Start, Rock, Paper, and Scissors.

2. Drag all 4 photos onto the desktoop.

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3. Click “Choose new sprite from file”.

4. Click “Desktop”.

5. Find the “start position” picture.

6. Click on “Costumes”.

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7. Next, click “Edit”.

8. Click the minus magnifier to zoom out. Now, click on the Eraser tool. Switch to a large eraser.

9. Now erase everything except the hand.

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10. Now click “Import” to bring in the “rock” position.

11. Select the “rock” position.

12. Just like you did with the “start” position. Click “Edit” .

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13. Erase everything but the hand in the “rock” position.

14. Now, repeat steps 10-13 for the paper and scissors pictures.

15. Once you have all 4 positions, label them as shown below.

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16. Next, go to google.com

17. Click on “Images”.

18. Search for “Rock”.

19. Once you find the image you want, drag it onto the desktop.

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20. Now, repeat steps 18-19 for “Paper” and Scissors.

21. Return to Scratch and click “Choose new sprite from file”.

22. Click on “Desktop” and select your rock.

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23. Name your rock sprite “Rock”. Now, click on the “Costumes” tab.

24. Click “Edit” and erase the background like you did with the hand positions.

25. Next, shrink the sprite.

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26. Repeat steps 21-25 for the paper and scissors.

27. Now, lets create the code to tell the hand to change positions. Click on the Rock sprite and drag the following code:

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28. Repeat this code on paper and scissors (figure the scissors code out for yourself):

29. Next switch to the HUMAN Sprite. So far, our code says if rock, paper, or scissors is clicked they broadcast a message saying they’ve been clicked. Now, let’s tell the HUMAN to switch to the right hand gesture (costume) depending on which one is clicked. Use this code for the HUMAN to switch to the rock gesture if the rock is clicked.

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30. Repeat a similar code for paper as shown below. Do the code for Scissors yourself.

You’re Done, But....

Along with posting Rock, Paper, Scissors on your blog, answer the following question:

Predict what the code will look like for the computer hand. How will it be the same as the HUMAN? How will it be different?