Standard 1/Middle School/Benchmark 4
Benchmark Question: How are molecules arranged in
Focus Question: What is the molecular motion and
arrangement of the molecules in the states of matter: solid, liquid, and
Students will observe models
of molecular motion in solids, liquids, and gases. The teacher will
demonstrate each state of matter and discuss the motion and arrangement of
molecules with the class.
For a gas, the teacher will
pour peppermint extract into a petri dish placed on the overhead projector.
Note the time it takes for everyone in class to notice the smell.
For a solid, the teacher
will pre-make a petri dish with clear, thick gelatin*. During the
demonstration, the teacher will drop dark food coloring around the inside
wall of the dish. Note the time it takes to evenly color the gelatin.
For a liquid, the teacher
will place a water-filled petri dish on the overhead projector and drop
food coloring into the water. Note the time it takes to color the water
Students will record their
observations on data tables during the demonstration. As a class, students
will compare the rate of movement to the molecular motion in different
states of matter and discuss real-world observations (e.g., room
fresheners, scratch and sniff magazine advertisements).
Alternative activity: Students may demonstrate solids, liquids,
and gases by using their bodies as molecules. In a solid, students should
be shoulder-to-shoulder and slightly vibrating. In a liquid, students must
be arm-to-arm, vibrating, and moving randomly but close together. In a gas,
students should take on the shape of the room by moving in straight lines
until they bounce off someone or something.
Extension: Students may design an experiment to
test the effects of temperature by using cold and warm water.
*Note: Gelatin is a suspension/mixture
called a colloid, but it can be used in this demonstration to exhibit
properties that are similar to a solid.