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Run the programs

I encourage you to use the information provided above to write and run these two programs. Experiment with the code, making changes, and observing theresults of your changes. Make certain that you can explain why your changes behave as they do.

Just for fun, see if you can add a drumbeat that keeps time as the cat walks.

I also encourage you to write the program described below.

Student programming project

Write a Scratch program named ForLoop03 . This program places a cat sprite, a slider variable, and a button on the stage as shown in Image K . The cat sprite has two costumes.

Image k. forloop03 output after clicking the green flag.

Missing image.
Image K. ForLoop03 output after clicking the green flag.

This program is an upgrade of the program named ForLoop02 , but is more complex than that program. In particular, this program uses the ability of onesprite (the button) to communicate with another sprite (the cat) by broadcasting and receiving messages.

You may have to do some online research to learn how to fire and handle broadcast events. Hint: See the bottom three blocks in the Events toolbox.

When the user clicks the button, this program behaves just like the program named ForLoop02 behaves when the user clicks the cat in that program. (Note, however, that the drawing of axes and lines was omitted from this program for simplicity.)

As in the previous program, this program executes its animation using a repeat block. Also as in the previous program, the number of times that the code in the repeat block is executed is specified by the current position of the slider.

Online version is available

A copy of this program has been posted online for your review (see Resources for the URL) . If you don't find the program using that URL, search the Scratch site for the usernamed dbal.

Summary

I began by providing a real-world example of the difference between a definite loop and an indefinite loop.

Then I presented and explained two Scratch programs that illustrate the Scratch equivalent of (or something similar to) a for loop in other programming languages. In Scratch, it is called a repeat loop. One of the programs caused a block of code to be executed a fixed number of times when the user clicked the greenflag. The other program caused a block of code to be executed a variable number of times when the user clicked a sprite.

I provided a brief introduction to the topic of animation and I explained the concept of costumes in Scratch. Both programs illustrate the use of costumes to implement crude animation that makes it appear that a cat sprite iswalking.

I also provided a student programming project.

What's next?

The next module will concentrate on other variations of Scratch loops.

Resources

General resources

Programs used in this series

Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Scr0370: The repeat loop in Scratch 2.0
  • File: Scr0370.htm
  • Published: 05/18/13
Disclaimers:

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.

-end-

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
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I start with an easy one. carbon nanotubes woven into a long filament like a string
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many many of nanotubes
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what is the function of carbon nanotubes?
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Source:  OpenStax, Teaching beginners to code. OpenStax CNX. May 27, 2013 Download for free at http://cnx.org/content/col11498/1.20
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