1) Why is Kevlar used to make bullet-proof vests? Weight for weight is five times as strong as steel.

2) Thinsulate material is good insulator because its very thick/thin fibres trap more air/water.

3) Sunblock with nanoparticles does not leave white streaks because the nanoparticles are too small/big to reflect/absorb the light.

4) The main products you get when you electrolyse salt water are...

Chlorine, hydrogen and sodium hydroxide

GCSE workshop: today, 7th November, 4:15 pm, N303.

How alcohol affects the human body?

L.O.: How beer and wine are made. How yeast can be used to ferment. what alcohol does to the human body. How the excessive use of alcohol can cause harm to society

Beer and wine are alcoholic drinks made by fermentation reactions that use yeast to convert sugars into ethanol.

sugar → alcohol + carbon dioxide

To get stronger alcohol, the alcohol must be concentrated by distillation.

• Ethanol is a depressant - it slows down signals in the nerves and brain.

• Small amounts of alcohol help people to relax, but greater amounts lead to a lack of self-control and loss of judgement.

Damage done by alcohol:o Brain: clouds judgemento Liver: can be damagedo Brain: shrinks and cause headacheo Heart: loss of potassium lower blood pressure,

cause irregularities.o Kidneys: pass too much urine

Intelligent packaging

L.O.:

How intelligent packing is used to keep food fresh.

Why wrapped food keeps longer than ‘open’ food?

Food goes off because of:

o bacteria and fungi that grow on or in the food

o chemical reactions that take place in the food, such as fats reacting with oxygen to make rancid products

The air in modern packaging is often replaced by gases such as nitrogen

Water can be removed by drying the food. Modern ‘freeze-drying' methods allow many food items to be dried so that they last longer.

How does mayonnaise work?

L.O.:

How emulsions are formed.How they are used in the food industry.

Immiscible liquids do not mix together

To stop the two liquids separating, we need a substance called an emulsifier.

The emulsifier in mayonnaise is egg yolk, which contains a chemical called lecithin

• Emulsion: mixture of oil and water than do not separate out

Lecithin

• Emulsifiers are molecules that have two different ends:

• a hydrophilic end - water-loving - that forms chemical bonds with water but not with oils

• a hydrophobic end - water-hating - that forms chemical bonds with oils but not with water

Examples of other emulsions:o mil (oil in water)o Creamo Butter

Emulsifiers:o egg yolk (contains lecithin)o Soup and detergent.