Lesson Plan for 8th Grade Physical Science
Duration: 46 minutes
Chapter 3: Solids, Liquids, and Gases
will be able to explain what happens to a substance during changes between a
liquid and solid state.
California Content Standards Addressed:
3. Each of the
more than 100 elements of matter has distinct properties and a distinct atomic
structure. All forms of matter are composed of one or more of the elements. As
a basis for understanding this concept:
d. Students know the
states of matter (solid, liquid, gas) depend on molecular motion.
e. Students know that in
solids the atoms are closely locked in position and can only vibrate; in
liquids the atoms and molecules are more loosely connected and can collide with
and move past one another; and in gases the atoms and molecules are free to
move independently, colliding frequently.
reactions are processes in which atoms are rearranged into different
combinations of molecules. As a basis for understanding this concept:
d. Students know
physical processes include freezing and boiling, in which a material changes
form with no chemical reaction.
progress is made by asking meaningful questions and conducting careful
investigations. As a basis for understanding this concept and addressing the
content in the other three strands, students should develop their own questions
and perform investigations. Students will:
e. Construct appropriate graphs from the data and develop
quantitative statements about the relationships between variables.
worksheet (see attachment)
the concepts of the molecules discussed the day before, pass out lab
worksheet, and explain important points to be careful of in the lab.
students will go to their previously assigned lab group and start the lab.
Lab equipment is already out for them. See lab worksheet attachment (35
minutes). The following is the procedure of the lab, note these are
the lab equipment. (5 minutes)
beaker of ice, salt, water and test tube. Clamp and start recording
temperature at start and every 30 seconds. (3 minutes)
beaker of salt water until it reaches +2°C.
Continue to record temperature, but stop stirring. (2 minutes)
the temperature reaches -2°C, carefully lift test tube
with clamp and drop a small ice cube in liquid water. (5 minutes)
test tube back in water, like before, and continue to stir and record
temperature. When the temperature reaches -4°C
stop recording. (8 minutes)
the remaining time in class, students will clean up, work on results,
conclusion, graph, and questions to answer. After the lab groups have
cleaned their station, then I will dismiss them by group. (12 minutes)
Student Prior Knowledge:
students have been learning about the nature of matter and the changes of
state. This lab helps to supplement their understanding of the different states
of matter and allow them to interpret a different type of graph. Furthermore,
students understand the differences between endothermic and exothermic
the temperature of the solid is decreasing within the test tube, it is unable
to find a pattern for the molecules to align and change its matter of state
from a liquid to a solid. Like magnetic marbles rolling too fast past each
other, they are unable to align until you slow them down and they can connect.
The marbles are like the molecules moving within the test tube. By adding the
ice cube, you are allowing the molecules to align and form a pattern.
Questions and Answers:
what happened to the temperature when the ice crystal was added to the
water when the temperature of the water was -2.5°C.
A: The temperature jumped up to 0°C.
temperature does your graph show for the freezing point of water? How can
you tell from your graph that this is the freezing point of water?
A: My graph shows that the freezing
point of water is at 0°C, as the water is freezing, the temperature of the
water stays constant at 0°C.
the temperature began to decrease below zero, was the water in the test
tube completely frozen? How can you tell from the graph?
A: Yes because once the temperature
of the water was completely frozen, the temperature began to decrease below 0°C.