Leonardo da Vinci was born on April 15, 1452 in Vinci, Italy. He was the illegitimate son of Ser Piero, a Florentine notary and landlord, but lived on the estate and was treated as a legitimate son. In 1483, Leonardo da Vinci drew the first model of a helicopter. It did not look very much like our modern day “copter,” but the idea of what it could do was about the same. Leonardo was an artist and sculptor. He was very interested in motion and movement and tried to show it in his art. In order to show movement, he found it helpful to study the way things moved. One subject he liked to study was birds and how they flew. He spent many hours watching the birds and examining the structure of their wings. He noticed how they cupped air with their wings and how the feathers helped hold the air. Through these studies, Leonardo began to understand how birds were able to fly. Like many other men, Leonardo began to dream of the day when people would be able to fly. He designed a machine that used...
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PENYAKIT JANTUNG Jantung manusia berdenyut 70 kali setiap minit atau 140,000 kali sehari. Kepentingan jantung tidak boleh dianggap mudah. Fungsi jantung terbahagi kepada beberapa bahagian: 1) membekal darah bersih kepada seluruh sistem anggota. 2) mengambil balik darah-darah yang digunakan. 3) menghantar ke paru-paru untuk diberikan udara bersih (oxygen). Dalam proses darah beredar, darah itu sekali lagi dibersihkan oleh buah pinggang (kidney). Buah pinggang menapis darah dari segala kotoran. Kotoran atau bahan terurai dibuang melalui urea (air kencing). Daripada statistik yang diperolehi, penyakit jantung adalah pembunuh utama penduduk di negara ini dan jumlah pesakit tidak pernah berkurangan sejak dua dekad lalu. Terdapat ciri-ciri yang mudah untuk mengenal pasti tahap kesihatan jantung individu adalah seperti: *Mudah lesu *Dada terasa sesak hingga menghadapi kesukaran untuk bernafas. *Aktiviti semakin terhad serta buku lali membengkak. ...