Science Organisms & Life Processes Conceptual 12–13 yrs

How Diffusion Works

扩散原理

Description

Explain diffusion as the net movement of particles from a region of higher concentration to lower concentration, and describe its role in moving materials (oxygen, carbon dioxide, glucose) in and between cells

Mastery Evidence

✓ Defines diffusion using particle theory
✓ Explains the direction of diffusion of oxygen and carbon dioxide at the alveoli
✓ Explains how cells get glucose from the blood using diffusion
✓ Identifies factors that affect the rate of diffusion (concentration gradient, surface area, distance)

Assessment Prompt

If your child was asked why oxygen moves from the lungs into the blood without the body needing to pump it, could they explain what diffusion is and why it always moves in one particular direction?