Thinking and Investigating 1. A chef shouts at his staff because they cannot prepare the food fast enough in his kitchen.
The assistant chef suggests the following menu modifications: (a) Serve ‘skinny fries’ instead of potato wedges. (b) Cook the food at 200o
C instead of 180o C. Explain why these suggestions would make the assistant chef ’s job easier.
2. Biological washing powders contain enzymes to break down grease on clothes. Manufacturers advertise these as being energy-saving washing powders because they work at lower temperatures. What do you think would be the ideal temperature to wash clothes at with a biological washing powder? What would happen if you used one of these washing powders on a very hot (90o
C) wash?
3. Why does it take a few seconds for magnesium ribbon to light when held in a flame? 4. When a person has a fever their body temperature rises. The reason for this is that the higher temperature should help to defeat invading infections. However, this affects all the reactions in the body and causes the person to feel very unwell. Explain the reason for this.
