Diffusion

• Diffusion

  The spreading out of particles from an area of higher concentration to an area of lower concentration
• Diffusion happens in both solutions and gases because the particles in these substances are free to move about randomly
• Types of diffusion

  • Diffusion of different gases through each other
  • Diffusion of perfume particles through the air
• The bigger the concentration gradient (the difference in concentration)

  The faster the diffusion rate
• Higher temperature

  Faster diffusion rate because the particles have more energy and move around faster
• Cell membranes

  • Hold the cell together
  • Let some substances move in and out of cells by diffusion
• Dissolved substances can move in and out of cells by diffusion

  Only very small molecules can pass through the cell membrane
• Big molecules like starch and proteins can't pass through the cell membrane
• Particles move through the cell membrane

  From where there's higher concentration to where there's lower concentration
• Particles move both ways through the cell membrane, but if there are a lot more particles on one side, there is net (overall) movement towards that side
• Larger surface area of the cell membrane

  Faster the diffusion rate, because more particles can pass through at once
• Diffusion of ink in water

  • Ink drop in cold water
  • Ink drop in warm water
• It would be great if all the ideas in this book would just gradually drift across into your mind by diffusion