SCIENCE INFO

11. Microorganisms live in a humid place which contains more water vapour.

12. The presence of water can be tested by using Cobalt chloride paper (changes from blue to pink) and dehydrated copper sulphate (white powder changes blue).

Cobalt chloride paper

13. Electrolysis technique can be used to coat a cheaper metal with a a layer of more expensive metal, like gold and silver.

Dechlorination with electrolysis treatment applied to an emblazoned bronze cannon

Cannon before treatment.

Applying electrolysis: the cannon is enclosed in a wire mesh.
Three steel cathodes (negative pole) are placed in contact with the cannon through a wire mesh, serving as anode (positive pole).

Cannon after treatment.

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1. The unit Kelvin is named after a Scottish physicist, William Thomson 1st Lord Kelvin (1824-1907)

William Thomson 1st Lord Kelvin

2. Sir Isaac Newton (1642-1727) discovered the gravitational force. The unit newton (N) is named after him.

Sir Isaac Newton (aged 46)

Sir Isaac Newton (old age)

3. The human body consists of about 50,000 million cells. Gene is a part of chromosome. It controls a particulars characteristics of an organism such as height, skin colour and shape of the nose.

Cheek cells

4. Cellulose which is a carbohydrate makes up most of the materials in the cell wall. Humans are unable to digest cellulose. Animals like sheep, cattle, and rabbit have bacteria in their digestive systems to break down the cellulose into simple sugars.

4. Density of an object helps us to determine whether the object is pure or not, as the density of pure substance is fixed. e.g. Pure gold has a density of 19.3 g/cm3. A piece of gold is not pure if the density is either higher or lower than the fixed density. So it is better to check the fixed density before deciding to buy a pure and precious substance like gold.

5. Do you know that a glass is not a solid? A glass is a super cooled liquid and the raw materials of glass are melted at 1400oC. Then, the liquid glass is cooled.

Hermit crap in a glass shell

6. Oxygen is the most abundant element found on Earth.

Oxygen molecule

7. Carbon is a non-metallic element, carbon has a very high melting point (over 3000oC ) and is also a good conductor of electricity.

8. Nuclear energy are also used to empower large ships and submarines. Some nuclear-powered ships need to be refueled after several years of journey or operations.

A ship empowered by neclear energy

9. James Prescott Joule (1818-1889), an English Physicist discovered that heat was a form of energy. The unit of measuring heat, Joule (J) was named after him.

10. The Sun is about 5000000000 years old and it contains hydrogen and helium.