1. © Oxford University Press 2009 10.6 Using lasers Laser pointers A laser pointer uses a low power laser. Teachers and lecturers sometimes use them to point out things of special interest.

2. © Oxford University Press 2009 More laser pointers A laser level projects lines onto surfaces to help builders keep things level. You use the spirit level to get the device level and then a laser projects a straight line onto the surface you need to work with. 10.6 Using lasers

3. © Oxford University Press 2009 More laser pointers The machines which scan barcodes at the supermarket use low-power lasers. The light does not spread out so each set of strips, representing a number, can be read. 10.6 Using lasers

4. © Oxford University Press 2009 Playing compact discs (CDs) A compact disc (CD) stores audio data such as music as a series of tiny pits which is read by a low- power laser. The laser light does not spread out so can shine on an individual pit. 10.6 Using lasers

5. © Oxford University Press 2009 Cutting CDs A CD-ROM works in the same way as a compact disc except the data read by the laser is converted into a range of things such as instructions and graphics for a computer game. A more powerful laser is used to burn the pits into the CD or CD-ROM. 10.6 Using lasers

6. © Oxford University Press 2009 High power lasers High power lasers can cut out a shape or drill holes in metals. The machine here is cutting a sheet of steel according to a pattern. 10.6 Using lasers

7. © Oxford University Press 2009 Cutting metal A firefighter uses a high power laser to free a person trapped in a vehicle, following a road traffic accident. It produces an intense beam of light that heats up the metal so that it can be cut away. A second firefighter holds the victim still to prevent him aggravating any injuries he might have. 10.6 Using lasers