1. © KCL/PENTECH/WCED 2000 Day length Conduction 1. The conductivity tells you how bad a material is at keeping the heat in. A big value for conductivity means heat is lost easily. A small value means warmth is kept in. Here are some conductivities for different materials DESCRIBE in your own words what the data in the table implies in terms of designing clothes to keep people warm. Material Comparative conductivity Paper 60 Cotton shirt 50 Cotton vest 48 Wool pullover 37 Air 24

2. © KCL/PENTECH/WCED 2000 Day length Conduction 2. A group of students decided to test some fabrics for their suitablility as a material to make warm jackets. They set up an experiment using tin cans that have been filled with hot water. On different tin cans they stick little jackets cut from different fabrics. They record the time it takes for the temperature of the water to drop from 50 to 30 degrees celsius. GIVE REASONS why you think this is a good or bad experiment. One can with the jacket made from a test material.

3. © KCL/PENTECH/WCED 2000 Day length Conduction A student discovered some apparatus in an old cupboard at school that could be used to compare the way different metals conduct heat. Here is a description of the apparatus. DRAW the apparatus. 3. There is a rectangular metal tank that is 15cm long, 7cm wide and10cm deep. On one of the long (15cm) sides are four holes in a line, 2cm up from the bottom of the tank. Into each of the four holes are inserted rubber bungs that have metal rods through them. The metal rods are 15cm long and approximately 0.3cm diameter. The rods are made of copper, aluminium, iron and brass.

4. © KCL/PENTECH/WCED 2000 Day length Conduction 4. Rods of different metals DESCRIBE in your own words how you think the apparatus is used. Thumb tacks held in place with wax Tank to hold hot water PREDICT what would happen.