Sugar Rush: The Science of Sweet

Transcription

1 Sugar Rush: The Science f Sweet FRAMEWORK I. Scientific and Engineering Practices II. Crss-Cutting Cncepts III. Physical Sciences SKILLS/OBJECTIVES T bserve the results f hands-n experiments and make inferences/draw cnclusins T understand that sugar cmes in different frms which affect the bdy in different ways. Nt all sugar is bad fr yu. T use learned infrmatin t have a better understanding f the sugar in fds the children cnsume n a daily basis. MATERIALS Clear beakers/cntainers Crn Syrup Red Fd Clring Measuring spns (tea spns) Sugar Flur Stirrers Timers Idine Slutin* Varius apples (e.g. Red Delicius, Glden Delicius, Gala etc) Knife (t be used by instructr nly) Petri dishes Paper Plates Ptat Chips Cheeris White Flur Sweet Ptates Ripe bananas American cheese Butter Egg whites NOTES

2 The idine slutin is t be prepared befrehand, material and instructins fr preparatin are fund n the final page. Activity #1 is mst apprpriate fr yunger children. Activity #3: The knife shuld be handled nly by the instructr. BACKGROUND Ask children basic questins related t the tpic: What is sugar? What fds is it in? What des it d fr ur bdies? Explain that sugar is ne f the main ways that humans get energy (they need t eat it because they cannt make within themselves, like plants) Explain that sugar is in lts f things besides candy and sda, it is fund in fruit, ygurt, bread, rice Hwever, it is ften called by it s scientific name carbhydrate (shw nutritin label, if handy) Explain that these carbhydrates cme in different frms; sme are big lng chains f mlecules (plymers, plysaccharides, starch) which are fund in bread and ptates vs. ther smaller mlecules (fructse, sucrse ) which are fund in fruit and table sugar. Activity # 1 Materials Wrksheet Absrbing Sugar Nne N Our bdy breaks big chains f sugar int smaller units f sugar (like the nes in fruit and candy) s that it can be digested Ptates have lng chains f sugar. We are ging t act ut hw these chains brken dwn. Chse ne child t be the enzyme amylase fund in the muth and anther child t be the enzyme maltase fund in the small intestine. Have the maltase stand n ther side f the rm. Stand in a line and jin hands. Explain t the children they are a lng chain f sugar (a plysaccharide). Mve twards the amylase. When yu reach the amylase, split int pairs. Tell them they are entering the muth and the enzyme amylase is breaking them int maltse, which cme in pairs. In pairs, mve twards the maltase n the ther side f the rm. When yu reach the maltase, break yur link with yur partner. Explain that they are passing dwn the thrat, thrugh the stmach until they reach the small intestine where they meet maltase. Maltase splits the pairs int individual sugars. Tell everyne that they are nw glucse, the same sugar fund in plants and a lt like the sugar they find in fruits, candy, juice etc

3 Activity # 2 Absrbing Sugar Demnstratin Materials Tw 500 ml beakers (r ther clear cntainer) Crn Syrup Red Fd Clring Measuring spns (tea spns) Sugar Flur Stirrers Timers Wrksheet N Explain that we will d an experiment t shw hw ur bdies react differently t tw kinds f sugar (starch vs. sucrse). Fill tw 500ml beakers half-way with crn syrup. Add a few drps f red fd clring t each beaker and stir t create the effect f artificial bld. Shw ne child hw t use the timer. Place ne teaspn f sugar n tp f the slutin in ne glass. Have the child recrd with the timer the rates at which the sugar is absrbed. Place ne teaspn f flur n tp f the slutin f the ther glass. Have anther child recrd with the timer the rate at which the flur is absrbed. Have the children cmpare the rates at which the sugar vs. the flur was absrbed. The reasn fr the different rates is because f the length/cmplexity f the mlecule we can readily absrb refined sugar int ur bld but cmplex starches take lnger. Talk abut the feeling f a sugar rush such as n Hallween this happens because it s the cnsumptin f a lt f refined sugars Activity # 3 Sweet Apples Materials Idine Slutin* Varius apples (e.g. Red Delicius, Glden Delicius, Gala etc) Knife (t be used by instructr nly) Petri dishes Paper Plates

4 Wrksheet N Nw we will shw that apples cntain sugar (starch) thrugh an idine test and cmparing the different distributins f starch in different types f apples. Present different types f apples that have been sliced and explain that apples have bth starch (cmplex sugars) and simple sugars, and as they ripen mre f the cmplex sugars becme simple sugars Try the different apples and predict which nes will have the mst starch. We can use idine t see which apples have the mst starch since idine turns blue/black when it reacts with starch. S, idine acts as a starch indicatr. Pur idine slutin int petri dishes s that they are abut 0.25 inches full Cut each apple in half and put the expsed surface face-dwn int the petri dish with the idine slutin. Let the apple sit fr 1 minute. Cmpare the different starch patterns represented by the black/blue pattern left n the different apples. If n black/blue pattern is left, yu can assume that all f the starch has been cnverted simple sugars. The apples with the mst starch shuld be less sweet since mre f the starch has nt been cnverted t simple sugars, des this match the predictins the children made? *Extra: See what happens when apples are left t react in idine lnger. Als, yu can test the difference between very ripe apples and rtting apples. Activity # 4 Extra Starch Tests Materials Ptat Chips Cheeris White Flur Sweet Ptates Ripe bananas American cheese Butter Egg whites Wrksheet N Present the children with a variety f fds and ask them which fds they think have starch in them (lng chains f sugar) and which have refined sugars Test it! Dip samples in petri- dishes cntaining the idine slutin r they can use pipettes. Discuss why their predictins were right/ wrng (The n/lw starch fds are cmpsed f fats, prtein r simple sugars). The kids may be surprised that sugar is fund in salty fds like ptat chips r fds that d nt seem sweet like flur.

5 *Extra: If there are fds left ver frm lunch/snacks the kids may test these fds t, fr further explratin f sugar cntent in fd. Hwever, it is ntable that nce the fd is tested, it may NOT be cnsumed. Instructr Cheat Sheet: Starch Ptat Chips Cheeris White Fur Sweet Ptates Ripe Banana American Cheese N r Lw Starch Butter Egg Whites *Idine Slutin Preparatin: Materials: Ptassium Idide Water Idine crystals Graduated Cylinder Large Bttle (capacity f abut 1.5 Liters) Aluminum fil Beaker Prcedure: In the beaker disslve 10 grams f ptassium idide in 10ml f water When it has disslved, add 2.5 grams f idine crystals Stir the mixture until the crystals have disslved Pur the mixture int the bttle Dilute the mixture with 1.14 Liters f water Cver the bttle in aluminum fil fr strage t minimize light expsure, and stre in a dark space Make sure the slutin is cmpletely mixed by shaking the bttle everyday fr several days CONCLUSIONS Clsing pwww with grup t reinfrce the basic take hme message r final discvery (in bld r therwise easily bservable) the lessn shuld help kids get t. Any cntinued investigatins prjects shuld be sent hme with them n paper in an easily fllw-able fr guardians. Shuld cntain basic highlighting f the lessn name and big message fr guardians as they nt be able t get all that infrmatin ut f the kids.