Concord: Understanding Diffusion

Everyday Diffusion

Display the following question:

"How can you smell popcorn or perfume before you see it?"

Students brainstorm possible explanations.

Other examples:

• Food coloring spreading in water
• The smell of coffee in a room
• Air freshener dispersing through a house

Co-Use Activity

Partners discuss one example and develop a simple explanation for how the smell or color spreads.

What Is Diffusion?

Explain:

Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration due to random molecular motion.

Introduce vocabulary:

• Diffusion
• Concentration
• Equilibrium
• Molecule
• Membrane
• Random motion

Show a simple diagram of particles spreading out over time.

Co-Use Activity

Student A explains diffusion in their own words.

Student B creates a real-world example.

Partners switch roles.

Guided Exploration of the Simulation

Students access the Concord Consortium Diffusion simulation.

Teacher demonstrates:

• Particle movement
• High and low concentration areas
• Equilibrium
• Random molecular motion

Ask:

• What happens when molecules start crowding together?
• Do molecules ever stop moving?
• What happens after equilibrium is reached?

Students record observations.

Co-Use Activity

Partners share a computer.

• Student A = Navigator
• Student B = Recorder

After several minutes, students switch roles.

Diffusion Investigation Teams

Divide students into teams.

Team 1: Concentration

Investigate:

• High concentration vs. low concentration
• How concentration affects diffusion speed

Team 2: Temperature

Use the temperature activity to determine:

• What happens when the temperature increases?
• What happens when the temperature decreases?

Team 3: Molecular Mass

Investigate:

• How molecule size affects movement
• Which molecules diffuse faster?

Team 4: Cell Membranes

Explore diffusion across a membrane.

• Which molecules move through?
• How does diffusion support living cells?

Teams complete an investigation sheet:

Variable               Prediction           Observation             Conclusion

Team Report-Out

Each team presents:

• Their investigation
• Evidence collected
• Conclusions

Exit Ticket

1. What is diffusion?
2. Why does diffusion occur?
3. What happens when equilibrium is reached?
4. How does temperature affect diffusion?
5. Give one real-life example of diffusion.

Success Criteria

Students can:

✓ Define diffusion.

✓ Explain molecular movement.

✓ Describe factors affecting diffusion.

✓ Use evidence from the simulation.

Co-Use Activity

Partners compare responses before submitting individual answers.

Diffusion in the Human Body
Discuss:

• Oxygen moves from the lungs into the bloodstream
• Carbon dioxide leaving the bloodstream
• Nutrients entering cells
• Waste products leaving cells

Co-Use Activity

Partners choose one body process and explain how diffusion is involved.