Lab: Observing Osmosis in Gummi Bears



Name Block Date Lab: Osmosis & Diffusion in Gummi BearsPurpose: To investigate the movement of water into and out of a Gummi Bear.Problem: Where is the concentration of H2O molecules highest: tap water, salt water, sugar water, or in the gummi bears? And where will it move because of that? How will we calculate if the water moved at all?Background Information:Gummy Bears are made of gelatin, starch, and sugar. Gelatin is a polymer (a huge molecule made of many monomers) that forms large three-dimensional matrices which give structural support to jellies and jams, and lots of other things that you use every day. Molecules are in constant motion, and tend to move from areas of higher concentrations to lesser concentrations. Diffusion is defined as the movement of molecules from an area of high concentration to an area of low concentration.The diffusion of water molecules through a selectively permeable membrane is known as OSMOSIS. Selectively permeable means that some molecules can move through a membrane while others cannot. Movement through membranes is called transport. Diffusion and osmosis are forms of PASSIVE TRANSPORT; this means that they do not need energy to move from areas of high concentration to areas of low concentration. ACTIVE TRANSPORT requires energy to transport molecules from low concentration to high concentration. OSMOSIS is the movement (transport) of water (small dots) through a selectively permeable membrane from an area of high concentration to an area of low concentration.Hypothesis:Circle your choices for each of the following: If the H2O concentration in tap water is (higher/lower) than the H2O concentration in a Gummi Bear, then Gummy Bears placed in tap water will (increase/decrease/remain the same) size. Circle your answers.If the H2O concentration in salt water is (higher/lower) than the H2O concentration in a Gummi Bear, then Gummy Bears placed in salt water will (increase/decrease/remain the same) size. Circle your answers.If the H2O concentration in sugar water is (higher/lower) than the H2O concentration in a Gummi Bear, then Gummy Bears placed in sugar water will (increase/decrease/remain the same) size. Circle your answers.13652534671000Materials: (3) 50mL beakers 399034048260Masking tapePermanent markerPlastic forkPlastic SpoonWaxed paper(3) Gummy Bears Tap waterSaltSugarRulerProcedures:Day 1-Obtain 3 beakers, 3 different colored Gummy Bears, and a ruler.Do NOT eat!!! If Mrs. Cooper sees you eat a gummy bear you will receive a zero!Label each of your beakers with masking tape (water/sugar/salt)Write your group member’s names and block on the label for all 3 beakers!Measure your gummy bears (in centimeters): from top to bottom (length), from side to side (width), and from front to back (height).Record the dimensions in centimeters in the data table on the next page.Find the mass of each bear (in grams). Record in data table. Use decimals to 100th.Determine which color bear you will place in which beaker (indicate in your chart).Set up your 3 beakers, each with 40mL of water. Add ? tsp salt to one, add ? tsp sugar to another, plain H2O in the last. Add one bear (should be completely covered) to the salt water beaker – write which color bear is submerged in salt water in your data table.Add the next bear (should be completely covered) to the sugar water beaker – write which color bear is submerged in sugar water in your data table.Add the last bear (should be completely covered) to the plain H2O beaker – write which color bear is submerged in plain tap water in your data table.Fill out the “predictions” column for each of your 3 bears. What do you think will happen?Place the beakers together up in the open cabinet above your lab station.Let them sit overnight until your next class period.Day 2-On the next class day, gently pour the water out of each beaker into the sink.Catch each bear using a plastic fork/spoon. Place the bear gently on a paper towel to blot dry; do NOT rub the gummy bear to dry it! It will disintegrate if handled roughly! They are very fragile after soaking!Measure the new length, width, and height of each gummy bear. Record in data tables.Find the mass of a piece of wax paper, then zero out your scale, place the dried gummy bear on the waxed paper to weigh in grams to the 100th decimal.Carefully find the mass of each of the 3 bears. Record in your data chart. When all data has been found, dispose of gummy bears in the trash can.Do NOT eat!!! If Mrs. Cooper sees you eat a gummy bear you will receive a zero!Calculate the volume (L × W × H). Round your answers to the nearest hundredth. 31750-49212500Data Table for Volume:Solution Tap WaterSalt WaterSugar ColorDimensionsGummy 1 color _______Gummy 2 color _______Gummy 3 color _______InitialBefore Soaking (day 1)PredictionFinal After Soaking(day 2)InitialBefore Soaking (day 1)PredictionFinal After Soaking(day 2)InitialBefore Soaking (day 1)PredictionFinal After Soaking(day 2)Length (cm)Width (cm)Height (cm)Volume (cm3) LxWXHData Table for Mass:Solution Tap WaterSalt WaterSugar ColorMass (grams)Gummy 1 color _______Gummy 2 color _______Gummy 3 color _______InitialBefore Soaking (day 1)PredictionFinal After Soaking(day 2)InitialBefore Soaking (day 1)PredictionFinal After Soaking(day 2)InitialBefore Soaking (day 1)PredictionFinal After Soaking(day 2)Gummy Bear massAnalysis:Calculate the percent changes in volume and mass that occurred after this experiment.% Change in Volume =(Final volume - Initial volume)/ Initial volume × 100 =%(-/) × 100 =% Change in Tap Water(-/) × 100 =% Change in Salt Water(-/) × 100 =% Change in Sugar Water% Change in Mass =(Final mass - Initial mass)/ Initial mass × 100 =%(-/) × 100 =% Change in Tap Water(-/) × 100 =% Change in Salt Water(-/) × 100 =% Change in Sugar Water042437300Make a BAR graph of the percent of change you calculated: Title the graph (what is being compared?) Place the data for all 3 bears on the same graph. Use the corresponding color of the actual gummy bear for your bars. Ex: Yellow gummy bears are represented by a yellow bar. Include a Key if needed. Title: ____________________________________________________2001751501251007550251%Change in Volume%Change in MassTap Water Gummy Bear%Change in Volume%Change in MassSalt Water Gummy Bear%Change in Volume%Change in MassSugar Water Gummy Bear Analysis questions: Answer the following: What happened to the bears when placed in tap water? Why?What happened to the bears when placed in salt water? Why?What happened to the bears placed in sugar water? Why? ____________________________________________________________Were your predictions accurate? Why or why not? ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________0282989007.Conclusion:Write 2 paragraphs which explain the results of this experiment using the concepts of osmosis and diffusion. Use the vocabulary you learned and be thorough in your explanations. Include specific data to explain your results and support your conclusions. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download