الفرق بين انتاجية القلب في الراحة والجهد من الواضح ان ايصال الدم بواسطة الشرايين التاجية الي عضلة القلب يزداد اثناء الجهد البدني لان وتيرة انقباض عضلة القلب تزداد والدم يحمل اليها الغذاء والاكسجين الضروريين لاستخلاص الطاقة.كذلك يزداد جريان الدم الي العضلات الهيكلية التي تحتاج الي كميات كبيرة من الاكسجين والغذاء.اما ازدياد جريان جريان الدم الي الجلد اثناء الجهد البدني فيعزى الي وظيفة الجلد في التخلص من فائض الحرار... Continue Reading
Piranhas Piranha, also called caribe or piraya, any of more than 60 species of razor-toothed carnivorous fish of South American rivers and lakes, with a somewhat exaggerated reputation for ferocity. They are known for their sharp teeth, powerful jaws, and vo... Continue Reading
Chemical reduction of Cyanobacteria bloom Cyanobacteria are algae that live in body of water, and can manufacture their own food. In certain conditions these algae can proliferate fast. This is called Cyanobacteria bloom, and it can become toxic and damage the ecological balance of the body ... Continue Reading
Tropical storm formation Picture taken from http://earthobservatory.nasa.gov/IOTD/view.php?id=87314Each year several tropical storms hit Florida, USA, causing damage and sometimes even deaths and injuries.A tropical storm forms when sea water temperature is 26 degrees or hig... Continue Reading
Potential energy
Every object in nature that located at certain height and gravity acting on it has potential energy. We can calculate use the equation Up=m*g*h. The energy released when the object falls.In elevating system we use weigh... Continue Reading
Enrage conservation In the above video we can see Roi sitting on his
skateboard on the upper side of the street, when he lift up his legs his skateboard
starts to roll down the street, when he wants to stop his skateboard movement, Roi
pull down his legs so that they... Continue Reading
arithmetic sequence Arithmetic Sequence
In an Arithmetic Sequence the difference between one term and the next is a constant. In other words, we just add the same value each time ... infinitely.
In General we could write an arithmetic sequence like ... Continue Reading
complex numbers multiplication A сomplex number is represented by z=a+bi , a and b are real numbers and i is the imaginary unit ,satisfying the equation i2 = −1.
For more information about complex numers link to:
http://blossoms.mit.edu/videos/lessons/comple... Continue Reading
معادلة الغاز المثالي يصف قانون الغاز البسيط العلاقة المتضمّنة ما بين الضّغط، الحجم، درجة الحرارة وكمّيّة الغاز.
قانون بويل ينصّ على: عند وجود كمّيّة ثابتة من الغاز تحت درجة حرارة ثابتة، يكون حجم الغاز بعلاقة معاكسة مع الضّغط.
قانون أفوغادرو ينصّ على: حجم الغاز يكون في ملاءمة مع كمّيّة الغاز تحت درجة حرارة وضغط ثابتين.
قانون تشارلس ينصّ على: مع حجم كميّة ثابتة من الغاز تحت ضغط ثابت يكون في م... Continue Reading
Polymers in our lives - Expanded Polystyrene
Ninth grade students have got
a project task about polymers, their importance in our everyday life and impact
on the environment.
One group has chosen to
concentrate on the Expanded Polystyrene (EPS) or by its trademarked br... Continue Reading
בולענים בולען הוא שקע הנפער בקרקע, בדרך כלל בפתאומיות. תופעת הבולענים עלתה לאחרונה לכותרות עקב היווצרות בולענים רבים באזור ים המלח.
בולענים נוצרים כתוצאה מזרימת מי תהום מתחת לפני הקרקע, שגורמת להמסת שכבות גיר או שכבות מלח, הגורם להווצרות לחללים ריקים (מערות) או חללים המכילים בוץ. לאחר היווצרות החללים בכמה מקומות בשכבה שמתחת לפני הקרקע, נוצרים סדקים ההולכים ומתרחבים בשכבת פני השטח, ולבסוף קורסת השכ... Continue Reading
Fossils arround the world What are fossils?
Fossils are traces of plants, animals, fishes, and other organisms from the remote past.
Scientists have learned that rocks are stacked in layers containing fossils with the oldest fossils at the deepest layers, and the ... Continue Reading
Sea level rise and its impact on Israel’s beach and coastal cliffs. Some 40 percent of the world's population lives within 62
miles (100 kilometers) of seashore, putting millions of lives and billions of
dollars' worth of property and infrastructure at risk.The biggest impact is expected to be on areas situated nex... Continue Reading
Question in C3 (Advanced) כתוב תוכנית אשר קולטת מערך דו מימדי דינמי בגודל NXN כאשר N חייב להיות מספר חיובי בין 5-10 כולל.
התוכנית תקלוט מספרים למערך.
התוכנית תדפיס את אורך הסדרה הגדול בכל השורה שמכילה איברים בסדר עולה.
לדוגמא:
5 3 2 1 1
8 7 8 7 8
9 8 7 9 1
4 5 4 2 5
1 2 3 4 5
יודפס:
4
2
3
3
1
... Continue Reading
Plastic recycling Plastic is manufactured by the polymerization
process, which connects monomers to create polymers. Common types of polymers in
our lives are presented in the table below:
Example... Continue Reading
Sea level rise risk Sea level is a term describing the altitude of the water at sea(Haifa) picture taken by :dina izGlobal warming due to human activity has countless examples all over the world.Global warming is basically the constant rise of the world average temperat... Continue Reading
Multimedia Questions
Inquiry Questions
