Diffusion and Osmosis Andreescience.com

Outline Learn the concepts of: –Passive Transport –Active Transport –Diffusion –Osmosis Observe Diffusion –How does temperature of water affect the rate of diffusion? Identify in writing the difference between passive and active transport; diffusion and osmosis, in cells. IWBAT

Transportation of Molecules Passive Transport -Movement of molecules across a semi-permeable membrane - no energy required Active Transport -Movement of molecules across a semi-permeable membrane against a concentration gradient with a protein - ENERGY – ATP

Diffusion Molecules of a substance moving from an area of high concentration to an area of low concentration –Random motion drives diffusion –Movement is based on kinetic energy (speed), charge, and mass of molecules –Example? (water)

Osmosis Diffusion of water through a semi-permeable membrane –Semi-permeable: permeable to solvents (WATER), but not to large molecules –High [water] to low [water] –Example? –What is “Reverse Osmosis”?

What is the Affect of the temperature of Water on the rate of diffusion? See Lab Sheet for procedure and data Chart HotCold

Procedure & Data Chart Initial Observations After 10 minutes Cold Water Hot Water Procedure 1.Use two clean glasses of equal size. Label one Hot, then fill it until half full with very warm water. Label the other Cold, then fill it until half full with cold water. WARNING: Do not use boiling hot water. 2. Add one drop of food coloring to each glass. Carefully release the drop just at the water's surface to avoid splashing the water. 3. Observe the water in the glasses. Record your observations immediately and again after 15 min.

Constructed Responses (in journal) 1.Describe with detail, what happened when food coloring was added to each glass. 2.How does temperature affect the rate of diffusion? 3.What is the difference between passive and active transport? What is the difference between diffusion and osmosis? This presentation was adapted from Diffusion and Osmosis and Osmosis