As students keep track of the time it takes for 100 g and 500 g of water to reach 50 C, have them relate the heat energy gained to mass. They may continue heating the water to 80 C and relate the mass and temperature changes to heat energy. Have students mix equal quantities of cold and hot water in a styrofoam cup and relate the initial and final temperatures to the transfer and conservation of energy. Set up a demonstration where one student uses a short piece of wood to push two students of different masses at the same time on in-line skates. This ensures the same force is applied to both students.
Students discuss the differences between force, motion, and mass.
Ask students to lift different masses through varying heights. This is an opportunity to infer the concept that work is related to force and distance. Have students brainstorm uses of simple machines. As they use different machines under varying conditions, they can relate load and effort forces and compare efficiencies. Have students discuss the scientific use of the term power compared with the common use of the term powerful .