Thermal energy and its transferIB MYP Sciences: Mind map

Exam questions on Thermal energy and its transfer

1. A mountaineering team in Nepal carries hot soup in a vacuum flask. The flask has two glass walls with a vacuum between them. The surfaces facing the vacuum are coated with shiny silver, and the stopper is made of plastic.
   Explain why the stopper is made of plastic rather than metal.2 marks
2. Fatima in Dubai heats a pan of water on a hob. She notices that the handle of a metal spoon left in the pan becomes warm, and that tea leaves in the water move around in circles.
   Explain how the convection currents that move the tea leaves are formed.2 marks
3. Students in Lima investigate how the surface of a can affects how quickly hot water cools. They fill a matt black can and a shiny silver can with 200 g of water at 80 °C and measure the temperatures after 10 minutes. The water in the black can was at 52 °C and the water in the silver can was at 63 °C. All other conditions were kept the same.
   Explain, using ideas about radiation, why the water in the black can cooled more than the water in the silver can.3 marks