Good Luck !

Mechanism of Ozone Formation and Ultraviolet Absorption

Mechanism of Ozone Formation and Ultraviolet Absorption
Kredit : http://www.youtube.com/user/Hendorr

This video demonstrates how oxygen gas in the atmosphere becomes ozone and how ozone protects us from ultraviolet radiation.

Food Web and Food Chain

Chapter 3 - Form 5

What's Eating You: Producers, Consumer, Decomposers
Kredit : http://www.youtube.com/user/mrsefdubose

Food web: Visualizing and Understanding Interdependence in Nature
Kredit : http://www.youtube.com/user/foodwebhead

Energy Pyramid and Food Web
Kredit : http://www.youtube.com/user/dmickowski

Food Chain and Web
Kredit : http://www.youtube.com/user/EZRenewalCredit

Ecosystem

Chapter 3 - Form 5

What is an Ecosystem?
Kredit : http://www.youtube.com/user/mrsefdubose

Radioactive Isotopes

Chapter 6 -Form 4 : Nuclear Energy

Radioactive Isotopes
Kredit : http://www.youtube.com/user/msnye

Alpha particles, beta particles and gamma rays.
Alpha particles are helium nuclei with a +2 charge, Big, heavy and slow moving, don't penetrate into materials, Very ionising, Blocked by paper.

Beta particles are high-energy electrons with a -1 charge; Quite small, move quite fast, Penetrate materials moderately, Ionise moderately, for every beta particle emitted, a neutron turns into a proton in the nucleus, some are blocked by thin Aluminium, but certainly blocked by tissue.

Gamma rays are electromagnetic waves with shorter wavelength (higher frequency) than x-rays, Opposite to alpha, Penetrate materials well, Weakly ionising, blocked by 7 cm of lead.

Differentiating Alpha, Beta and Gamma Waves

Chapter 6 - Form 4 : Nuclear Energy

Differentiating Alpha, Beta and Gamma Waves
Kredit : http://www.youtube.com/user/Hendorr