Overall Expectations
- demonstrate an understanding of the properties and uses of fluids.
Specific Expectations
- explain the difference between solids, liquids, and gases in terms of density, using the particle theory of matter
- explain the difference between liquids and gases in terms of their compressibility
- explain in qualitative terms the relationship between pressure, volume, and temperature when a liquid (e.g.,
water) or a gas (e.g., air) is compressed or heated - explain how forces are transferred in all directions in fluids (Pascals law)
Materials
a large open space, eg gym, school yard, cleared space in classroom
Important Terminology
gas, liquid, solid, particle, heat, volume, pressure, temperature, condensation, evaporation, freezing, thawing, sublimation,
Background Knowledge
- basic postulates of particle theory of matter
- How heat affects the motions of particles
- How heat affects the volume of solids
- conduction, convection, radiation
Hook
Due to a lab accident, your science teacher and your drama teacher have switched bodies, so, until your science teacher can find a cure, we are going to do an interpretive dance about the particle theory of matter.
Lesson Sequence
Find or create a large open space.
Explain to the students that they shall be playing the part of particles of matter. Review the basic postulates of the particle theory of matter, and Newtons laws of motion. Remind the students that for safety, all collisions should be interpretive, and not real. They have a force field that will not let another particle get closer than a foot. Their speed should be a normal walk for hot, a slow walk for room temperature, and baby steps for cold.
Starting as a gas, they have to walk around the room in a straight line, and can only change direction when they hit something. Let this go for about 30s, then ask the students what they observed regarding how much of the room they visited, how easy it was to move, how close they were to other particles, and how much space they had, and how often they "hit" the walls of the room. Remind them that when they "hit" another particle, they can transfer energy (heat), and that they number of times they hit is the temperature.
The teacher should take a walk through the gas, and ask the students how easy it is for the teacher to move through the gas, how often the object contacted a particle of gas. Ask them if the teacher is "hit" on all sides equally.
Using your teacher powers, create an invisible wall and compress the gas for 30s and repeat the questions. Point out that both pressure and temperature are dependent on the number of hits, compare these with the uncompressed state.
Pick one corner to be "down". Using your teacher powers, cool the room. Ask the students how often they hit the invisible wall compared to when they were hot. Explain that there is less pressure on the wall now so it will start to fall to the bottom of the room.
Keep cooling until the gas liquefies and flows to the bottom of the room. Remind them that as a fluid, there's still enough room (elbow distance) between them so they can still move around, but are attracted to each other so they can't go beyond the "surface". Re-ask the questions.
Try to compress the fluid, ask the students to compare how easy it is to compared to when they were a gas.
The teacher can then move through the fluid, showing how liquid flows around objects. The teacher should ask the same questions as when he moved thought the gas.
The teacher should now use his powers to slowly freeze the liquid by having the student put their elbows down, right hand on the shoulder of the student in front of them and their left hand on the shoulder of the students to their left. Ask the students to compare the volume they occupied as a warm fluid and a cold one. Repeat the demonstration of compressing the solid and moving through it and re-ask the questions.
Culmination
Review what we've learned on an overhead.
Break the class into heterogeneous groups and assign each one of the following questions and have them create anchor charts to answer them.
- What is the relationship between temperature, pressure, and volume.
- Explain compressibility by the particle theory of matter.
- Show the different properties of solids, liquids and gasses.
- Explain density using the particle theory of matter.
- Explain Pascal's Law using the particle theory of matter.
Key Questions
How much of the room they visited as particles when they were solid liquid and gas. How easy it was to move in these states. How close they were to other particles? How much space they had? How often they "hit" the walls of the room? How compressible are gasses, liquids and solids? How are volume, temperature and pressure related to the particle theory of matter?
Assessment
Use an anecdotal assessment of the children during the exercise to see if they can stay in character.
Use the anchor charts they create to assess their understanding of the particle theory of matter. This is a formative assessment.
Enrichment
Since this is mostly groupwork and whole class activities, there is little room for enrichment
Remediation
As a mostly kinisthetic exercise, no remediation should be needed. The assessment is done on groupwork, so the stronger children in the group will help the weaker.
References
Bubbles in the hot tub : a guide to getting in and out of hot water : an integrated unit for Grade 7/8 / written by Derek Totten ... [et al.] ; Kyn Barker (project lead).
Publisher [Ontario : s.n. ; Waterloo, Ont. : distributed by Graphics Visual Solutions, University of Waterloo], 2001.