60 likes | 207 Views
Fresh Smell Put your hand up when you can smell the spray. Lesson 1 : Diffusion. Objectives: Define diffusion in cells List factors that affect the rate of diffusion Describe how cells may be adapted to facilitate diffusion. Experiment #1: Balloon
E N D
Fresh Smell Put your hand up when you can smell the spray.
Lesson 1: Diffusion Objectives: Define diffusion in cells List factors that affect the rate of diffusion Describe how cells may be adapted to facilitate diffusion
Experiment #1: Balloon • Smell the box and the balloon. Record observations in your notebook. • Smell the box and balloon again at the end of class. • Explain what happened and why. Experiment #2: Salt • Fill the beaker with water. • Test the water for salt with silver nitrate in a test tube. • Place a solution of salt in visking tubing and place it in a beaker of water. • Test the water for salt with silver nitrate after 20 minutes. • Draw the salt particles in the beaker at the beginning and after 20 minutes.
Experiment #3: Ammonia • Wet the cotton with the ammonia solution and then place it in a cork at the end of a glass tube. • Start the stopwatch and record in a table how long it takes to turn the litmus paper blue every 2cm until 14cm. • Graph your data. Remember graphs need the following: • use pencil and ruler. • use the whole page. • axis must be linear • label axis with units • write a title • plot the data correctly • draw a curved line • of best fit Answer: Why does the litmus paper change colour? Why do the different tubes have different results? Be sure to talk about particles.
Whatisdiffusion? • It is the random, passive movement of particles from an area of high concentration to an area of low concentration until the concentration is equal http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html Factors affecting diffusion: a) Concentration gradient: the greater the difference in concentration the faster the rate of diffusion. b) Temperature: An increased temperature will cause particles to move faster, hence diffuse faster c) Surface area: Increased surface area creates more space for diffusion. Example: lungs, small intestine
Summary _________is the net movement of a ______ or a ________ from an area of _________concentration to an area of _________ concentration as a result of the __________ movement of the particles. Diffusion gas high lower random solute Name 3 substances that move across your body’s cell membranes by diffusion.