Relate observations regarding the addition of energy to particle motion.
view of students, there are two 1000 ml beakers, one filled with cold water, and the other filled with hot water. The
instructor dropped a drop of food coloring into each beaker at the same time. Students observed and recorded a minimum
of three macroscopic drawings of the contents of the beaker at given time intervals. Students recorded data in this
way so they could see how each beaker looked after the same amount of time.
After examining the drawings and collaborative discussions, students drew storyboards of
what they believed was happening at the particle level (microscopic) to explain their macroscopic observations.
Almost all students said that they had prior knowledge that warm water moves
faster than cool water (fluids). When asked how they knew this and what evidence they had to support this claim, they
said they learned this idea in middle school, but couldn’t site any evidence to support the idea.
After some questioning by the instructor, one student finally realized that the evidence that particles of warm fluids
have greater motion than cold fluids was how the food coloring diffused at different speeds.
Since particles of food coloring mixed at different speeds in water of
different temperatures, this must indicate that the particles of warm water are moving faster, or with greater motion (greater
and more frequent particle collisions), than the cold particles.