Ask Mr Brain....all will be explained

PUBLISHED : Wednesday, 03 November, 1999, 12:00am
UPDATED : Wednesday, 03 November, 1999, 12:00am

Some fax machines do not use ink so how do they produce printouts? JOYCE CHAN Facsimile or fax machines consist of a scanner, a transmitter and a printer. The scanner scans a page to make an electronic representation of text or graphics. It turns the information on the original into a series of dots, each represented by a bit that has a value of either one (on), or 0 (off). This data is then sent along telephone lines to another fax machine.

When it receives data, a fax machine can use a variety of methods to print out. Thermal printers do not use ink. Instead they use heat to print out the information on heat- sensitive paper. However, a drawback with the paper is that it turns brown and the print fades after a while.

The thermal printer produces images and text by pushing electronically heated pins against the paper which then turns black.

Why do you never find a spider in old cobwebs? Because the spider has usually moved out by the time a web is easily visible.

Some species of spiders build fresh webs every morning to trap small insects for food and destroy them again in the evening. Other species build new webs when their present ones are no longer effective.

When the old dusty webs can been seen they are already abandoned. Fresh webs are almost invisible and very sticky.

Why do my muscles hurt after doing exercise? The pain is caused by inflammation of the muscles. Over-exercising or exercising improperly causes small tears in the muscle fibres. Various proteins and other materials can leak from inside cells which the immune system tries to destroy.

With training, muscles should become less likely to tear or get damaged.

People who exercise regularly should not feel pain.