Standard 2/Middle School/Benchmark 3
Benchmark Question: How does heat energy change the
physical arrangement and motion of atoms and molecules?
Focus Question: How can bbŐs in a petri dish be
manipulated to model the arrangement and motion of atoms/molecules when
heat energy is added and removed?
The teacher should place
about one hundred bbŐs in a petri dish with a lid and place the dish on the
overhead projector. The teacher should roll the bbŐs, so they clump in one
spot. The teacher should discuss with students that this represents the
arrangement and motion of atoms/molecules in a solid.
The teacher should tell
students that heat energy is being added as he or she gently wiggles the
petri dish (the teacher should use enough movement to make the bbŐs move
freely but not wildly). The teacher should discuss that this change
represents a solid to liquid phase change.
Finally, the teacher will
shake the petri dish more rapidly while keeping the dish flat on the
overhead projector. BbŐs should rapidly ricochet off the sides and off each
other. The teacher should discuss with students that this represents more
heat being added and a phase change from liquid to gas.
Reverse the process to show
heat energy being removed.