## Category Archives: Science

## How I Pass Chemistry

I am very excited to present to you the first version of my chemistry project created for high school students. It already covers some very important chemistry concepts, but the program will be developed further as I am studying this subject and still have much to discover.

This software can be used by students to check their own work and to understand and remember patterns that are usually hard to memorize but that are asked to be known in international exams such as IGCSE or A-Level exams.

I already had the chance to present my work at the TEDx event and have developed it some more into this final first version.

This version of the program includes:

- a self-generating periodic table with information about each element and the 2-D structure of every element,
- a module to find out the type of bond between two selected elements and the empirical formula of the compound,
- graphs to observe the patterns of the periodicity of elements (e.g.: observing the trend of melting points across period 3),
- a calculator that gives information about the compund introduced based on the data it has.

Some screenshots of the program:

## What was the initial purpose of the internet?

The computer network, called ARPANET at the beginning, was created in 1969 in the U.S. for military reasons. In case of an atomic war, it was to provide the link between the central points of great power control. Firstly, it was put at the disposal of scientists, then it became a global computer network accessible to all.

## Who was the first man to exceed the speed of sound?

U.S. Air Force pilot Charles Elwood Yaeger, on October 14, 1947, with a jet Bell-X-1.

## Can diamonds burn?

Although they belong to the group of ** gems**, diamonds can burn because they are made of pure carbon.

## Downloads

From this page you can download some apps made by me …

*Ana Ispasoiu, CSB*

*29.09.13
*

**In general:**

• A database is a persistent, logically coherent collection of inherently meaningful data, relevant to some aspects of the real world.

**In other words,**

A database is any collection of related data.

For example, we want to have some records of some students from a school. A simple table would look like this:

Students

Name | Surname | Age | Gender |

John | Stewart | 13 | M |

Andrew | Thorne | 13 | M |

Emma | Roberts | 16 | F |

*F**ig.1 A simple database table of students with attributes and records*

* *Databases have:

● Entities

● Attributes

● Relationships (cardinality)

**Entity** is the table in general. In Fig.1, the entity is the table ‘Students’ itself.

**Attribute** is the property that describes the entity. In the above example, there are 4 attributes (the columns with name, surname, age,and gender).

**A record** is a row in a table that contains data. Without them, we won’t have any data in our entity.

…..

More details and the whole article you can have if you register on my blog and download

this** application** and** presentation** from** here**.

If you are asked for a setup password, please send me an e-mail.

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If you are interested in electricity you can read a presentation with the basics from here. *You need to be logged in to view this.*

## The World of Fractals

A **fractal** is a mathematical set that has a fractal dimension that usually exceeds its topological dimension and may fall between the integers.

Fractals are typically self-similar patterns, where self-similar means they are “the same from near as from far”.Fractals may be exactly the same at every scale, or, as illustrated in *Figure 1*, they may be nearly the same at different scales.

The definition of fractal goes beyond self-similarity *per se* to exclude trivial self-similarity and include the idea of a ** detailed pattern repeating itself**.

*Figure 1*

Self-similarity, which may be manifested as:

- Exact self-similarity:
*identical at all scales; e.g. Koch snowflake* - Quasi self-similarity:
*approximates the same pattern at different scales; may contain small copies of the entire fractal in distorted and degenerate forms; e.g., the Mandelbrot set’s satellites are approximations of the entire set, but not exact copies, as shown in Figure 1* - Statistical self-similarity:
*repeats a pattern stochastically so numerical or statistical measures are preserved across scales; e.g., randomly generated fractals; the well-known example of the coastline of Britain, for which one would not expect to find a segment scaled and repeated as neatly as the repeated unit that defines, for example, the Koch snowflake* - Qualitative self-similarity:
*as in a time series* - Multifractal scaling:
*characterized by more than one fractal dimension or scaling rule*

As mathematical equations, fractals are usually nowhere differentiable, which means that **they cannot be measured in traditional ways**. An infinite fractal curve can be perceived of as winding through space differently from an ordinary line, still being a 1-dimensional line yet having a fractal dimension indicating it also resembles a surface.

The mathematical roots of the idea of fractals have been traced through a formal path of published works, starting in the 17th century with notions of recursion, then moving through increasingly rigorous mathematical treatment of the concept to the study of continuous but not differentiable functions in the 19th century, and on to the coining of the word *fractal* in the 20th century with a subsequent burgeoning of interest in fractals and computer-based modelling in the 21st century.

**The term “fractal” was first used by mathematician Benoît Mandelbrot in 1975.** Mandelbrot based it on the Latin *frāctus* meaning “broken” or “fractured”, and used it to extend the concept of theoretical fractional dimensions to geometric patterns in nature.