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No sprites

There are a few things that we can conclude by viewing Image 1 . First, there are no sprites in this program. The program consists solely of

  • The Stage, shown in white in the upper left,
  • A small program consisting of three scripts shown in the rightmost panel,
  • Two variables shown in orange near the middle of the center panel and also shown in gray/orange in the upper-left corner of the Stage.

The toolbox buttons

If you have worked through some Scratch v2.0 examples, you will recognize that the material in the lower-center panel is always associated with one of the followingten toolbox buttons in the upper-center panel:

  • Motion
  • Looks
  • Sounds
  • Pen
  • Data
  • Events
  • Control
  • Sensing
  • Operators
  • More Blocks

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

When one of those ten buttons is clicked, it becomes completely colored and the tools associated with that button are displayed below it. The orangebutton labeled Data has been selected in Image 1 .

The Data toolbox

The lower-center panel of Image 1 presents the Data toolbox showingthe tools that are exposed by the Databutton.

Tools in the Data toolbox: When you first click the Data button, only two gray buttons are exposed in the toolbox. One gray button is labeled Make a variable and the other gray button is labeled Make a list . The two orange variables and the orange tools shown in the Data toolbox of Image 1 were produced by clicking twice on the button labeled Make a variable and entering a name for each variable.

Create two variables

Click here for detailed instructions on creating variables.

Image 1 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 Data toolbox of Image 1 ) associated with each variable. As you have probably learned from working through example programs, you can drag theseblocks into the programming area in the rightmost 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 manually perform the last two operations by checking or clearing the checkboxes next to the variables but the bottom two tools allowyou to perform that operation as part of a running program.)

Specifying the values

After dragging a programming block from the Data toolbox into the programming area, you can:

Questions & Answers

how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele 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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