Y5 children have been learning about materials which conduct heat and materials which can act as insulators to prevent heat from escaping. They were challenged to use this knowledge to make a flask to keep 200ml of water as warm as possible for as long as possible. Water in the control flask (a plain beaker with no insulation) lost 9 degrees of heat in only eight minutes. Some of the Y5 flasks were so good they only lost 1 or 2 degrees of heat in TWELVE minutes. Pretty impressive.