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  • the Stage, shown in white in the upper right,
  • a small program consisting of three scripts shown in the middle panel, and
  • two variables shown in gray near the top of the lower-left panel and also shown in the upper-left corner of the Stage.

The toolbox buttons

If you have worked through the Scratch tutorials, you will recognize that the material in the lower-left panel is always associated with one of the following eighttoolbox buttons in the upper-left panel:

  • Motion
  • Looks
  • Sounds
  • Pen
  • Control
  • Sensing
  • Operators (previously Numbers)
  • Variables

In other words, when you click on one of the buttons in the upper-left panel, it exposes a set of tools that you can use to write your program. Those toolsappear in the lower-left panel.

When one of those eight buttons is clicked, it becomes completely colored and the tools associated with that button are displayed below it. The orangebutton has been selected in Image 1 . Since you can't read the label on that button, I will tell you that the label on the orange button reads Variables .

A full-size view of the Variables area

Image 2 presents a full-size view of the two left-most panels from Image 1 showing the tools that are exposed by the Variables button.

Tools in the Variables toolbox: When you first click the Variables button, only two gray buttons are exposed in the bottom panel of Image 2 . One gray button is labeled Make a variable and the other gray button is labeled Make a list . The orange material in Image 2 was produced by clicking twice on the button labeled Make a variable and entering a name for each variable.

Image 2. a view of the variables area of the scratch user interface.

Missing image.
Image 2. A view of the Variables area of the Scratch user interface.

Create two variables

Click here for instructions on creating variables.

Image 2 shows that this Scratch program contains two variables with the following names:

  • Counter
  • counter

I purposely spelled the names of the two variables the same and made them differ only by the case of the first letter to illustrate that Scratch is casesensitive insofar as the names of the variables is concerned. Even though these two variable names contain the same letters, they are two different variablesbecause one name begins with an upper case "C" and the other name begins with a lower-case "c".

Allowable operations for variables

There are four programming blocks (in the bottom panel of Image 2 ) associated with each variable. As you learned from working through the tutorials, you can drag theseblocks into the programming area in the center pane in Image 1 to actually write the program. Thus, there are four different operations that you can perform on a variable:

  • You can set the value of the variable to a specified value.
  • You can change the value of the variable by a specified value.
  • You can show a variable on the stage.
  • You can hide a variable.

(You can actually perform the last two operations simply by clicking the block with no requirement to drag it into the center pane. Severaloperations that required double-clicking prior to v1.4 can now be accomplished with a single click.)

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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