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Awesome Osmosis. Really smelly demonstration…. Put a few drops of vanilla in a balloon Shake the balloon, then wait about 30 seconds Smell the outside of the balloon. What’s going on?.
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Really smelly demonstration….. • Put a few drops of vanilla in a balloon • Shake the balloon, then wait about 30 seconds • Smell the outside of the balloon
What’s going on? A drop of vanilla was added to the inside of a balloon and soon the aroma could be detected on the outside of the balloon. EVIDENCE INFERENCE
Remember Diffusion? • What is the definition of diffusion? The movement of particles From an area of high concentration To an area of low concentration
Osmosis is a special kind of diffusion • WATER molecules move across a membrane • The movement is still from an area of high water concentration to an area of low water concentration
Guess which way the water will move… 75% water molecules 25% water molecules
Correct-a-mundo! 50% Water Molecules 50% Water Molecules
Meanwhile, back at the smelly balloon……. A drop of vanilla was added to the inside of a balloon and soon the aroma could be detected on the outside of the balloon. EVIDENCE INFERENCE
Infer why the balloon smells Osmosis made the “smell particles” move through the balloon membrane because they crashed into the inside of the balloon and accidentally fit through the tiny holes.
Notice that only the WATER molecules move Salt doesn’t cross Proteins don’t cross
Shaker cube demo… Start with all of the red and white beads on the same side. Shake the cube a bit. OBSERVE: • Which beads, or particles, fit through the holes? INFER: • Why won’t the red beads move? APPLY: Which color beads would represent water molecules “doing” osmosis? What would represent the cell membrane?
When talking about cells, osmosis means water molecules crossing the Cell Membrane
Picture this…. • You and your friend are alone in a small boat in the middle of the ocean • There is no fresh drinking water • Your friend decides to just drink ocean water • You decide to just wait for some rainfall
Osmosis says….. • 85% water in the cells lining the stomach • 75% water in ocean water • Which way will the water molecules move? • Your friend loses & is • Even more dehydrated !
Picture this… • You are snowboarding at Powder Mountain. • There are 20 centimeters of fresh, sparkling powder under you. • The day is sunny, but only -10o C that’s cold! • You forgot your chapstick…
Osmosis says… • 15% water in the air • 85% water in your lip cells • Which way will the water molecules move? • Can you say chapped lips?
Osmosis… The movement of WATER molecules across a cell membrane.
Quick Quiz Question 1 What will happen when a cell that is 75% water is placed into a beaker of salt water that is 65% water? • The cell will shrivel because water will move out of the cell • The cell will shrivel because salt will move out of the cell • The cell will plump because water will move into the cell • The cell will plump because salt will move into the cell
Quick Quiz Question 2 What is the difference between osmosis and diffusion? • In diffusion, particles move from high concentration to low concentration. In osmosis, particles move from low to high. • In osmosis, salt particles move across a membrane, making things swell. In diffusion, only water particles move. • Osmosis is a special type of diffusion where water moves across a membrane.