I need help with my Biology lab please see the attached files

Diffusion and Osmosis Lab Page 1 of 8 Student Name: _________________________ Diffusion and Osmosis Lab NOTE: This lab requires waiting periods that span 4 DAYS for completion! A llow enough time to finish all steps of the 4 -day process before the lab is due! Don’t forget to take pictures of yourself performing the experiments. Supplies Needed: 2 similar, clear glasses 2 tea bags Tap water Tincture of iodine (or Providone Iodine – Betatdine) Cornstarch Plastic sandwich bags Camera Clear plastic cups 2 eggs White vinegar Corn syrup (Karo syrup) Liquid measuring cup 3 jars with covers Online Discussion Topic : What was the reason you soaked the eggs in white vinegar? Give a general overview of your experimental results and why the egg increased and decreased in size when moved between the water and corn syrup. Disc ussion R equire ments : 1 original new posting that contains your response to the assigned topic of discussion (Start a new thread, don’t hit reply to the assigned original topic post); 2 replies to coursemate’s posts. Introduction : Diffusion is the movement of a substance from an area of high concentration to an area of low concentration. Osmosis is a specific type of diffusion dealing with the diffusion of water across a semi permeable membrane from an area of high concentration to an area of lower concentration. To review the concepts of diffusion and osmosis, visit the following website s: http://www.northland.cc.mn.us/biology/Biology1111/animations/passive1.html http://www.biology.ualberta.ca/facilities/multimedia/uploads/alberta/dif.html Diffusion and Osmosis Lab Page 2 of 8 Student Name: _________________________ Part 1 : Temperature and Diffusion : When making tea, tea bags are always added to hot water…why? What effect does temperature have on diffusion? W rite your hypothesis before you begin the experiment below . Write Your Hypothesis (use the if -then format described in the Scientific Method lab ): __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ Supplies Needed for this section :  2 similar, clear glasses  2 tea bags  Hot and cold tap water (see details below) Complete each of the following steps: 1. Fill one glass with 237 mL ( 1 cup ) of hot tap water (this should be water that is as hot as you can get it from the tap without additional heating ). 2. Fill a second glass with 237 mL ( 1 cup ) of ice -cold water (to get water ice cold, place several ice cubes in a cup of water and allow the water to chill, then, right before going to the next step, remove the ice cubes with a spoon and use only the chilled water for the experiment s, so that the ice cubes do not interfere with your results ). 3. Place one tea bag in each glass . 4. Make observations at one minute intervals for 15 minutes . 5. Record your observations in the table below: Diffusion and Osmosis Lab Page 3 of 8 Student Name: _________________________ Table 1 : Observe the differences between the 2 glasses…be sure to include color(s) and the distribution/locati on of the colors. Time (minutes) Hot Water & Tea (Glass 1) Cold Water & Tea (Glass 2) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 6. Answer the following questions: A. Describe the rate of diffusion in the two glasses. __________________________________________________________________________ __________________________________________________________________________ B. Was your hypothesis correct? __________________________________________________________________________ __________________________________________________________________________ C. What does this experiment tell you about how temperature affects the rate of diffusion? __________ ________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ Diffusion and Osmosis Lab Page 4 of 8 Student Name: _________________________ Part 2: Diffusion across a Semi -Perm eable Membrane : In this experiment you will observe the diffusion of a substance across a semi -permeable membrane. Iodine is a known indicator for starch. Remember that an indicator is a substance that changes color in the presence of the substance it indicates. So… if iodine permeates the membrane ( passes through the plastic bag), then the iodine will cause the white starch inside the membrane to turn a dark purple -black color. Supplies Needed for this section :  Tincture of iodine (available in the first aid section of any pharmacy or store, a small bottle should cost about $3.00) You can also use Providone Iodine (Betadine) if necessary.  Cornstarch  Plastic sandwich bags  Clear plastic cups  Tap water Complete each of the following steps: 1. Fill a plastic sandwich bag with 5 cc ( 1 teaspoon ) of corn starch and 120 ml ( ½ cup ) of water . 2. Seal the bag ( Note: cheaper, thinner bags actually work best ). 3. Fill a plastic cup half full with water and add ~3 0 drops of iodine . 4. Place the bag in the cup so that the bag of cornstarch is submerged in the iodine/water mixture. 5. Wait 15 minutes and then make observations. Do not touch the bag during the 15 minutes. 6. Answer the questions below : A. Define permeability. __________________________________________________________________________ __________________________________________________________________________ B. Define semi -permeable. __________________________________________________________________________ __________________________________________________________________________ Diffusion and Osmosis Lab Page 5 of 8 Student Name: _________________________ C. Record your observational results ; be sure to describe any changes that occurred during the experiment. __________________________________________________________________________ _______________________________________________________________________ ___ D. To which substance is the plastic bag permeable? __________________________________________________________________________ __________________________________________________________________________ E. Why did the iodine enter the bag? __________________________________________________________________________ __________________________________________________________________________ F. Why didn’t the starch pass through the bag in to the water/iodine solution in the cup ? ____________ ______________________________________________________________ __________________________________________________________________________ G. How is the plastic bag like a cell membrane? __________________________________________________________________________ __________________________________________________________________________ Part 3: Osmosis Supplies Needed for this section :  2 eggs  White vinegar  Corn syrup (Karo syrup)  Tap water  Liquid m easuring cup  3 jars with covers Diffusion and Osmosis Lab Page 6 of 8 Student Name: _________________________ Complete each of the following steps: 1. Place 2 raw eggs in a glass jar. 2. Pour enough white vinegar into the jar to completely cover the 2 egg s. 3. Cover the jar and allow i t to sit for 1 -2 days (until shell s are dissolved ). ONCE THE SHELL IS DISSOLVED: 4. Fill a liquid measuring cup with 150 ml of tap water. 5. CAREFULLY remove 1 egg from the jar with a spoon, drain away all vinegar from the egg and spoon, and then gently place the egg in the measuring cup of tap water. (Note: Be very careful not to puncture or break the membrane of egg! ) 6. Observe the size and how the egg feels without the shell…be careful and gentle! 7. Record the total volume of the egg and the tap water in the table below . 8. Gently remove the egg from the measuring cup of water, drain any excess water and place the egg in a clean empty jar. 9. Add enough corn syrup to the jar to completely cover the egg and loosely cover the jar using a lid or paper towel . 10. Repeat the volume -measuring process (steps 4-7) for the second egg. 11. After recording the volume of the second egg and the water in the measuring cup, gent ly remove the egg from the measuring cup of water, drain any excess water and place the egg in a clean empty jar. 12. Add enough tap water to the jar to completely cover the egg and loosely cover the jar using a lid or paper towel. 13. Allow the eggs to sit undisturbed in the jars for approximately 1 day. AFTER 24 HRS: 14. CAREFULLY remove egg from the corn syrup jar. Record your observations in the table. Diffusion and Osmosis Lab Page 7 of 8 Student Name: _________________________ 15. Repeat the volume -measuring process (steps 4 -7) for the egg in the jar of corn syrup and for the egg in the jar of water. 16. Swap! Place the egg from the syrup jar in the water jar and let sit for 1 day. Place the egg from the water jar in the syrup jar and let it sit for 1 day. AFTER ANOTHER 24 HRS: 17. Repeat the volume -measuring process (steps 4 -7) for the egg in the jar of corn syrup and for the egg in the jar of water. Volume of Egg & Water - Volume of Water = Volume of Egg Egg #1 without Shell (day 1) - = Egg #1 after corn syrup (day 2) - = Egg #1 after water (day 3) - = Egg #2 without shell (day 1) - = Egg #2 after water (day 2) - = Egg #2 after corn syrup (day 3) - = 18. Answer the following questions: A. Describe the size of the eggs, comparing their original size to their size after the shells were dissolved and they were removed from the vinegar. __________________________________________________________________________ __________________________________________________________________________ B. Describe the changes you observed in the volume of Egg #1 when it was removed from the jar of corn s yrup. __________________________________________________________________________ __________________________________________________________________________ Diffusion and Osmosis Lab Page 8 of 8 Student Name: _________________________ C. Describe the changes you observed in the volume of Egg #1 when it was removed from the jar of tap water. __________________________________________________________________________ __________________________________________________________________________ D. Describe the changes you observed in the volume of Egg #2 when it was removed from the jar of tap water. __________________________________________________________________________ __________________________________________________________________________ E. Describe the changes you observed in the volume of Egg #2 when it was removed fro m the jar of corn syrup. __________________________________________________________________________ __________________________________________________________________________ F. What changes did you notice about the consistency of the corn syrup from th e beginning of the experiment to the end? How can you explain these changes? __________________________________________________________________________ __________________________________________________________________________ G. When the egg was placed in the water after being removed from the syrup, in which direction did the water move (in relation to the egg)? __________________________________________________________________________ ___________________________________________________________ _______________ H. Why do grocery store owners spray fresh fruits and vegetable with water? __________________________________________________________________________ __________________________________________________________________________ I. Roads ar e sometimes salted to melt ice. What does this do to plants around the roadside and why? __________________________________________________________________________ __________________________________________________________________________ J. If a bowl of fresh strawberries is sprinkled with sugar, a few minutes later the berries will be covered with juice. Why? __________________________________________________________________________ __________________________________________________________________ ________