خورشید فایل صوتی ندارد The Sun Ever since early humans first became aware of their environments, they have recognized the importance of the sun’s heat and light to life on the earth. People around the… خورشید

ترکیب زمین فایل صوتی ندارد The Composition of the Earth As a child, you might have wondered what you would find if you could dig a hole deep into the center of the earth. Scientists… ترکیب زمین

تاریخ حیات بر روی زمین فایل صوتی ندارد The History of Life on Earth For centuries, people have found fossils-the remains of organisms that once lived on the Earth. But it has only been in… تاریخ حیات بر روی زمین

میمون های بزرگ فایل صوتی ندارد The Great Apes If you have ever visited a zoo, you have probably noticed that people seem to be fascinated by the great apes. This fascination is probably due… میمون های بزرگ

فتوسنتز فایل صونی موجود نیست Photosynthesis Did you know that plants can “eat” light? Green plants obtain their energy directly from the sun, by converting light energy into chemical energy. This process is called photosynthesis.… فتوسنتز

وراثت و آزمایش مندل فایل صوتی موجود نیست Heredity and Mendel’s Experiments For thousands of years, people have understood that many characteristics of plants or animals are transmitted from parent to offspring. Because of this… وراثت و آزمایش مندل

جدول تناوبی عناصر فایل صوتی ندارد The Periodic Table of the Elements Every chemistry student is familiar with the periodic table of the elements. This famous chart arranges the elements-that is, the different varieties of… جدول تناوبی عناصر