Glass Miss Jan

Page 46 practical 1. Cut glass – use file 2. “Melt” glass and smooth the end of the tube 3. Heat the middle of the tube, then put the two unheated ends to make the middle thinner 4. Bend glass ► Complete the table at the bottom of page 46 WEAR SAFETY GLASSES AT ALL TIMES ALL glass must return to the container

Natural glass: Obsidian

Relay reading – NMS 2 pages ► Work in pairs ► Person on the left read page 50 – write down 3 important points ► Person on the right read page 51 – write down 3 important points

Glass – solid…??

Compare the plastics with glass Plastic Glass

NMS 2 p51 1. Glass was first made when soda (sodium carbonate) was accidentally heated with sand (silicon dioxide). These compounds react like this: sodium carbonate+silicon dioxide  sodium silicate+ carbon dioxide Na 2 CO 3 +SiO 2  Na 2 SiO 3 +CO 2

2. The raw materials used in making glass are: silicon dioxide sodium oxide calcium oxide Other compounds can be added to make glass with different properties (such as colour).

3.Different types of glass include: Soda glass – the “ordinary” glass used for most purposes Borosilicate glass – which contains boron, is tougher and is able to resist higher temperatures and so is used in cookware and lab equipment Cut glass – which contains lead, is more “sparkly” and is used in ornaments and costume jewellery Fibreglass – consists of a bundle of glass fibres embedded in plastic and is used to support and strengthen the plastic Safety glass – consists of a layer of plastic used to hold two sheets of glass together so that the glass doesn’t shatter when it’s broken

4.Properties and uses of glass include: PropertyUse Reasonably low melting pointcan be easily shaped into different objects Transparent to lightglasses (both kinds) Attractive shiny appearanceornaments Electrical insulatorheavy duty electrical fittings Insoluble in waterhold drinks like wine and beer Chemically unreactivecan be safely used with a wide range of materials

5 a.Light bulbs – transparent, easily moulded, doesn’t react with oxygen, even at high temperatures b.TV screens – transparent, easily moulded c.Telescopes – transparent, easily moulded into different shapes of lenses d.Drink bottles – transparent, easily moulded, doesn’t react chemically with water and dilute solutions of weak acids (fruit juices) e.Acid bottles – transparent, easily moulded, doesn’t react even with concentrated solutions of strong acids