tips See photo. electricity darkness

Transcription

1 Air Pressure There are two setups for this. Ask for assistace puttig them together. Blowig up a balloo Pump the syrige attached to the cotaier holdig the balloo. What happes to the balloo? Is the syrige attached to the balloo? Are you pushig air i or pullig air out? Magdeburg Spheres This was origially doe with metal hemispheres sealed with grease. However, acrylic plates sealed with a o-rig works quite well. This really requires two people, at least briefly. Oe perso should hold the two plates with big, black hadles o them together with the thick o-rig betwee them. The other perso should pump 2 the syrige. Try to pull the two plates apart after dup you ve 3 pumped oce 4or twice. Ca you? Air Pressure -- Explaatio We mostly are ot aware of the ormal atmospheric air pressure aroud us. These activities highlight its existece by removig air creatig a vacuum from a small regio so the pressure does ot exist. I the case of the balloo, removig air from aroud the balloo permits the air withi the balloo to expad to occupy the space abadoed by the air we ve removed. I the case of the Magdeburg spheres, removig the air betwee the plates removes the balace of pressures o the two sides of each plate resultig i a very large force from the air outside the plates pressig the plates together. explaatio 3 acrylic plates (2 w/ hadles) ad a acrylic cylider pressure box 1 pressure 3 large o-rigs pressure box 2 pressure balloos ad small plastic cup pressure box 3 pressure large, plastic syrige (o eedle) pressure box 4 pressure plastic tubig with coectors ad valves pressure box pressure tips See photo. darkess

2 Are Slugs Makig Them Sluggish? Pick two of the three cyliders. Which oe do you thik will wi a race dow the iclie? Try it. Were you right? Are there slugs iside the slow oe? Are Slugs Makig Them Sluggish? -- Explaatio Where the mass is affects how thigs roll. The closer the mass is to the ceter, the less eergy it takes to get it rollig. The oisy oe is about 1/2 full of salt. The salt slides aroud ad steals eergy from the rollig so it goes slower. Try aother pair of the cyliders. What is the coectio betwee the way the cyliders behave ad what happes i Goig for a Spi? explaatio 2 dup ramp by prep room door to hallway 1 o box hoops, solid disk, salt-filled disk ( blue tape) zip-lock bag i Optics I 2 optics 1 blocks for proppig ramp up oscillatios box 3 oscillatio 4 sake - purple flael filled with plastic beads (short with o head or tail) double pedulum dble ped. tips See photo. Sake goes at bottom of ramp to stop thigs. darkess

3 Blowig Up a Really Big Balloo Put your fist aroud the ope ed of the sack ad hold it up close to your mouth ad blow i like blowig up a balloo. How may times to you have to blow to blow the whole thig up. Now use two hads to hold the bag all the way ope ad away from your face. Now blow towards the opeig of the bag. What happes? How may times do you have to blow to blow it up completely? Ca you explai why oe way works better tha the other? Blowig Up a Really Big Balloo -- Explaatio Whe you blow directly ito the bag, all the air i it has to come out of you. That takes a lot of huffig ad puffig. Whe you hold it out away from you, you create a curret that pulls more air i with it. This is like the draft i your shower (especially whe you re ot stadig i the water blockig the flow). The air you blow, tugs o the air immediately ext to it which tugs o the air ext to it ad so o. explaatio 2 dup plastic sack about 6 log ad 1 diameter optics 2 1 optics tips darkess

4 Boilig by Had Hold the ball with more liquid i it i the palm of your had. What happes? How do you udo it? Does it work upside dow? How about sideways? If othig happes, you may have cold hads, or the liquid may already be well-heated from someoe else s hads. Boilig by Had -- Explaatio The liquid i the glass has a very low boilig poit - much lower tha water. The boilig poit is low eough that the heat from your body will cause the liquid to boil. The liquid that boils away turs ito gas that fills the rest of the bulb. The gas pushes the remaiig liquid out ito the other bulb the same way that you ca push all the liquid out of a straw by blowig air (a gas) through the straw. explaatio 2 dup blow glass with colored liquid iside optics 2 1 optics tips Mout some way so its ot so breakable? Avoid with small childre? Have broom ad dustpa hady? Not good outside if hot (too little temperature cotrast) or widy (blows over). darkess

5 Boucig Magets See if you ca stack the magets so that they do t stick to oe aother. How may magets ca you stack so oe of them touch each other? What happes whe you jiggle the stack up ad dow? Try makig pairs of magets ot stick to other pairs of magets. Is the spacig the same as with sigle magets? Boucig Magets -- Explaatio Magets have two sides called poles (usually labeled North ad South for geographic reasos). Like poles repel ad opposite poles attract. Magets have poles because there are electros goig aroud i little circles iside the material. explaatio 2 dup dowel rods o a woode base - paited white ad red E&M shelves - usually up high 1 va de Graaff plastic covered dout magets zip-lock back i optics I 2 optics tips darkess

6 Bug s Eye View of the World Look through the set of small squares. What do you see whe you hold it very close to your face? What do you see if you hold it farther away? What happes if you look at thigs close up? What happes if you look at thigs far away? Try rotatig the sheet as you look at someoe or somethig. Try getly bedig the sheet as you look at somethig. Now try lookig through the large rectagle o the sheet. What do you see whe you hold it very close to your face? What do you see if you hold it farther away? What happes if you look at thigs close up? What happes if you look at thigs far away? Try rotatig the sheet as you look at someoe or somethig. Try getly bedig the sheet as you look at somethig. Is there a differece betwee the frot side ad the back side of the sheet? Try bedig the sheet eough so that you ca 2look through both the large rectagle ad the squares at the dup same time 3 (oe behid the 4 other). What do you see? Bug s Eye View of the World -- Explaatio Lookig through the squares you see multiple copies of the same thig. This is the way most isects see the world through their compoud eyes. Lookig through the squares, thigs are right-side-up ad smaller. This is what a cocave les does. (Cocave meas it is hollowed out o oe or both sides istead of beig flat.) Lookig through the rectagle, thigs are up-side-dow ad somewhat smaller whe your eyes are far from the sheet. If you get up close to the rectagle, thigs will appear right-side-up ad big. This is what a covex les does. (Covex meas explaatio it bulges o oe or both sides istead of beig flat.) Notice above that the leses are t supposed to be flat, but the plastic sheet is defiitely flat. Feel the sheet. These are Fresel leses, the thi ridges you ca feel as roughess o oe side of the plastic are little slices of a curved les. ~8.5x11 plastic sheet of Fresel leses Leore/ optics 1 1 optics tips darkess

7 Capture Your Shadow Put your had over the paper, ad the move it away. What happes? Does it matter how log you leave your had there? Does it matter if you re touchig the paper? Capture Your Shadow -- Explaatio The paper is glow-i-the-dark paper. Whe you shie light o it, it keeps the light, so the paper glows. Your had blocks the light ad stops the paper from glowig, util the light from the lamp recharges it. How do you thik it works? What do you thik the light is for? Take a look at Ghostwritig ad Glow-i-the-Dark Pictures. How are they similar? How are they differet? explaatio 2 dup Gree paper mouted o board optics 1 box 1 optics 1 Desk lamp with UV CF bulb lights box 2 lights 3 4 tips darkess

8 Cartesia Divers Squeeze the bottle. What happes to the colored fish iside? Ca you make oe hover? What causes the up ad dow motio? Look at what happes to the shape of the fish whe you squeeze the bottle. Cartesia Divers -- Explaatio Water does t squeeze very well, so whe you squeeze the bottle, the geies get squished a tiy bit. This squishig reduces the space the air occupies iside the fish. This makes the geie heavier relative to its size tha it used to be. It ow siks. If you squeeze just right, you ca make a geie hover i the middle of the bottle. You ca try this effect at home with balls of alumium foil. You will probably have to work a bit to get the fish s weight ad size correct. Some fish have air sacs. The fish ca use its muscles to chage the size of the air sacs which chages the buoyacy of the fish so it ca swim dow or up easily. explaatio 2 dup soda bottle with 3 colored fish iside fluids shelf/pressure box 1 pressure tips darkess

9 Casper the Friedly Ghost BE CAREFUL NOT TO HIT PEOPLE AROUND YOU WHILE DOING THIS. Wave the woode wad with a black tip vertically over the blue tape lie o the floor. Stad so that you are o the same side of the wad as the projector. What do you see? What do people stadig other places i the room see? Does it matter how fast you move the wad? What happes if you move closer to the projector or farther from it? How do you thik this works? Casper the Friedly Ghost -- Explaatio The projector is showig a slide of Casper. The light bouces off the wad ad back to your eyes. You see the whole image istead of just a slice of it because your eye retais iformatio for a little while (persistece of visio). explaatio 2 dup Casper slide otebook 1 otebook Slide projector o carousel or cotrol cords eeded metal cabiet by hall door 2 oscillatio woode poiter lights box 3 lights 4 tips darkess

10 Climbig a Sad Due Hold the tube vertical like a telephoe pole with the ball bearig at the bottom of the tube. Ca you make the ball bearig climb to the top of the sad? (It s o fair just turig the tube over!) Climbig a Sad Due -- Explaatio This is oe of may examples of large objects risig to the top of a collectio whe shakig. It s a little surprisig because the ball bearig is defiitely heavier tha the grais of sad. However, it s also much larger so the sad ca fall dow i holes made by the big ball bearig, but the big bearig is ulikely to fid a hole made by the sad s movemet that is big eough for it to fall dow. explaatio 2 dup ~12 log tube filled with gree sad ad a ball-bearig tips This is aother good oe for the adults. oscillatios i tube with stadig wave bars oscillatio darkess

11 Corrallig Your Voice Fid both eds of the phoe (woode pieces attached to a red tube). Fid someoe to use the phoe with you. Try talkig oe at a time. How softly ca you talk ad still be heard? Ca you hear if you talk this softly without the phoe? Try talkig at the same time. Ca you still hear each other? Corrallig Your Voice -- Explaatio The air i the room carries your voice. (Could you talk to someoe o the moo without a radio?) Normally, whe you speak your voice fills the room. By speakig through the tube, your voice oly has to fill a small space, so the perso o the other ed ca here you whisperig. Whe Mark Twai worked o steam ships, speakig tubes were used so that the captai at the top of the boat could sed orders to the egieer three stories dow at the bottom of the boat. explaatio 2 dup two woode hadles with few meters of corrugated red plastic tubig Tom 1 optics tips Separate the two eds of the phoe ad put two sets of istructios out. darkess

12 Crazy Mirrors Stad a polished pipe sectio ear various objects, icludig the cartoos o the table. How does the image i the pipe compare to the real object? What happes if you tip a pipe a little? What happes if you tur a pipe o its side? Crazy Mirrors -- Explaatio Whe light hits a polished surface like these pipes it bouces off at the same agle it hit like a ball bouced off the floor. Because the pipes are curved, this seds light i strage directios so the image is distorted. This distortio is related to the distortio produced by makig a flat map of the Earth, which is really roud. explaatio 2 dup Chrome pipe about 1.5 diameter ad 8 log up to 4 sectios optics 1 box 1 optics 1 4 Hallowee images that will come out ormal reflected i the pipe otebook 2 otebook 3 4 tips darkess

13 Dead Ball Which ball does t act like a ball you d wat to play baseball with? Are there ay other differeces you ca detect betwee the two balls (without breakig them or ayoe or aythig)? I geeral, what sorts of thigs just lie there whe you drop them o the groud? What sorts of thigs bouce? What does this tell you about the isides of the balls? Dead Ball -- Explaatio The ball that does t bouce is slushy iside. Whe part of it is ready to bouce back from the floor, the other part is still headig toward the floor. the two parts get tagled up ad the ball does t get aywhere (sort of like whe your feet ca t decide which way they re goig). The ball that does bouce is hard iside. Whe part of it is ready to bouce back up from the floor, the other part kows this ad bouces back too (sort of like whe two dacers both kow where they re goig ext). explaatio 2 dup pair of black boucig ad o-boucig balls ow zip-lock bag i ball sectio 1 optics tips The boucig ball bouces quite well, so watch out for it strayig or breakig thigs. darkess

14 Disappearig Colors Take the frot sheet of gray plastic ad rotate (as though it were the had of a clock) it i frot of the jar slowly. What happes to the light comig through the two gray sheets aroud the bottle? What happes to the light comig through the bottle? Disappearig Colors -- Explaatio The gray sheets are polarizers. They oly let light through if it s lied up the right way like pickig up a log stick through a picket fece ad tryig to brig it back through. Whe the sheets are at right agles to each other almost o light gets through. Whe they are lied up the same directio, all the light that gets through the first sheet also gets through the secod sheet. The fluid i the beaker is cor syrup - dextrose. It rotates the light the way you rotate your had to pull a stick through a picket fece. The cor syrup rotates differet explaatio colors of light differet amouts. The color that is lied up with the sheet i your had is the oe you see because more of it gets through. As you rotate the sheet, differet colors are lied up so you see differet colors. 2 dup jar of Karo without a label ad with lid taped o with blue tape (straw-colored) 2 polarizers - heavy, gray plastic optics 1 box optics 1 box 1 optics 1 2 optics 1 desk lamp with CF bulb lights box 3 lights 4 tips Tape back polarizer to bottle. Eve with CF bulb, try ot to have the bulb too close to the polarizer lest it melt. Prop the other polarizer i frot of the bottle. See photo. darkess

15 Doppelgagers Use the protractor at the top of the mirrors to set the mirrors 90 apart. How may dice do you see? Which directio are the dots: all the same, opposite, rotated? Brig the mirrors closer together. What happes to the umber ad directio? Move the mirrors back farther apart. Now what happes? Look at Seeig Ifiity. What differeces do you see? What similarities do you see? Doppelgagers -- Explaatio Light from the room bouces off the dice ad hits oe of the mirrors. Some of the light that bouces off that mirror the hits the other mirror. Sice the mirrors are t exactly opposite each other, the image rus off the edge. How fast depeds o the agle betwee them. explaatio 2 dup protractor 2 square mirrors taped together at oe edge pig or ghost optics 1 optics 1 zip-lock bag i optics 1 1 optics 1 2 optics 1 3 optics 1 4 tips Balace the protractor o the top of the mirrors. Mirrors store i flael sack. See photo. darkess

16 Evaescet Colors Pick up the pompom. Tilt it aroud i the light while you re lookig at it. What do you see? Is it the same all the time? Where are the colors comig from? Try to figure out how the colors you see are related to what you re doig with the pompom. Evaescet Colors -- Explaatio These colors come from iridescece. Ordiary, white, light is made of may colors. Whe the light hits a thi layer of somethig, like oil o water i the street after it rais, some colors bouce towards your eye ad some do t ad you see colors. Iridescece is ofte evaescet (fleetig) because the agle you look at the film from chages its apparet thickess. explaatio 2 dup effective thickess thi film -- thickess greatly exaggerated effective thickess thi film -- thickess greatly exaggerated had sized plastic pompom optics 1 1 optics tips darkess

17 Eye of the Storm DON T TOUCH THE GLASS SPHERE WITH METAL. Move your figers aroud ear the surface of the sphere. What happes to the colored lies? Put your had behid the globe? What do you see? Sap, clap, say Boo. What happes? Hold the fluorescet tube up to the globe. Does it matter where you hold the tube? Eye of the Storm -- Explaatio This works like lightig. The globe is filled with gases. Small sparks jump from the ball at the ceter to the outer globe. As they ru ito the gas molecules, they cause them to emit light. The lies ted to be attracted to your had because you re stadig o the groud ad makig the jump easier for the sparks. explaatio 2 dup Eye of the Storm fluorescet tube optics 2 box i its ow foam est optics 2 box i pipe isulatio 1 optics 2 2 optics tips Watch out for kids wavig the tube aroud. darkess

18 Fa Cotrol By adjustig the strobe light but ot touchig the fa: Ca you chage the fa s directio? Ca you make it go forwards, backwards, forwards? Ca you make it stop? Fa Cotrol -- Explaatio You ca oly see whe there s light. Strobe lights tur o ad off very quickly. Your eye ca t see that fast. (This is why motio pictures are possible.) If the strobe light matches the fa s speed, you will always see the blades i the same positio so it looks like it s stadig still. However, you ca still feel the air beig moved by the fa, so you kow the fa is still ruig. If the strobe light is a little slower, the fa appears to spi forward slowly because the light turs o whe the fa has moved past its previous positio. If the strobe is a little faster, the fa appears to spi backwards slowly. This is why explaatio car wheels i movies ofte seem to go the wrog way. 2 dup strobe light light sources 1 oscillatio fa cart (or box fa) shelves over carts 2 oscillatio 3 4 tips The strobe is less aoyig i a lit room. darkess

19 Firefly Pick up the gree stick i your had. Is it hot, warm, or cool? Ca you see it i the dark? Ca you see it i the light? Ca you see to read with it? Firefly -- Explaatio This is called chemilumiescece meaig chemical light. The ame shows its differece from ordiary light bulbs ad firelight. Chemilumiescece produces visible light without heat. The most famous example of it is the firefly or lightig bug. So far people are poor imitators of the firefly: fireflies are 88% efficiet but so far the best people ca do is 23% efficiecy. explaatio 2 dup glow stick top of shelves ear PPLAY stuff 1 optics tips Stock up o glow sticks aroud Hallowee although they ca usually be foud with campig stuff. Break the stick at the begiig of the evet; oe stick should last plety log. darkess

20 Floatig Face Start out by stadig directly i frot of the face. Now walk from sideto-side while watchig the face. How does the face look as you move? Where do the eyes appear to be lookig as you stad i differet spots? Now try the same thigs with oe eye shut (or covered). Do you get the same effects? Floatig Face -- Explaatio The face is reversed from a real face (the ose is farthest from you) ad the light placed below it so that the shadows chage i ways we are t used to seeig. This gives the illusio of the eyes watchig wherever we stad. explaatio 2 dup Floatig face self cotaied i ow box optics 1 box 1 optics tips The bulb i this has bee kow to wader from its socket i trasport. You ll hear it rattlig if this has happeed. Uscrew the back plate ad retrieve as ecessary. darkess

21 Freezig a Liquid with a Maget Pick the jar up ad tilt ad shake it. What do you observe? Now hold the maget agaist the jar ad tilt ad shake agai. How does the stuff i the jar behave ow? What happes if you rub the maget aroud agaist the side of the jar? What happes to the surface? Freezig a Liquid with a Maget -- Explaatio The jar cotais oil (motor oil) mixed with tiy pieces of iro. I the Earth s weak magetic field, the mixture flows like a liquid - there is eough oil that the bits of iro slide by each other easily. Whe you put the maget ear the jar, the filigs lie up ad are attracted to each other because the maget magetises them. If you move the maget aroud, the iro bits move aroud some too ad ca lie themselves up better so you ca see patters like you ca sometimes see i ice. Geerally, the iro explaatio bits do t stay magetized whe you move the maget away, but if they have bee held i positio for a log time, they may stay a little magetized - like paperclips holdig o to each other briefly after you remove the maget you used to pick them up. 2 dup small glass jar (foutai pe ik jar) with sludge at bottom moderately strog maget optics 1 optics 1 1 optics 1 2 optics tips Shake this up whe you set it out as the iro filigs will settle ad ot move much util they get stirred back ito the oil. darkess

22 Ghostwritig Hold the flashlight vertically over the paper ad write with it. Ca you leave a mark o the page? Ca you write your ame? Does it matter how fast you move the flashlight? Why do you thik we have this i the dark room? How do you thik it works? Take a look at Capture Your Shadow ad Glow-i-the-Dark Pictures. How is it similar? How is it differet? Ghostwritig -- Explaatio The light from the flashlight is stored i the coatig o the paper. The coatig emits light (ot ecessarily the same color) later. The loger you hold the flashlight i oe place, the more light is absorbed so that the spot will glow brighter ad loger after you move the poiter away. If the paper were i a brightly lit room, all of it would be charged up ad the releasig the light so you could t tell a differece betwee where the flashlight had bee ad where it had t bee. Notice that the flashlight shies very blue. Blue light is more eergetic tha the red light of a laser poiter ad so works better to stimulate the paper. explaatio 2 dup blue flashlight with blue LED i it Gree paper attached to board batteries optics 1 box optics 1 box optics 1 1 optics 1 2 optics 1 3 optics 1 4 tips darkess

23 Glow-i-the-Dark Pictures Take the crayos ad draw a picture o a piece of white paper. Hold your picture uder the light bulb. What happes to your drawig? What colors show best? What happes to the white paper? What happes to white clothig? Compare this to Capture Your Shadow ad Ghostwritig. How are they similar? How are the differet? Glow-i-the-Dark Pictures -- Explaatio The crayos cotai a material that stores light ad releases it as a differet color light. The black light bulb is sedig out ultraviolet light. Huma eyes do t detect ultraviolet light, so it gets called black light. Some isects do detect ultraviolet light. The crayo i your drawig stores the ultraviolet light ad the releases it as light that we ca see. The crayos ad the paper for Ghostwritig ad Capture Your Shadow work o similar priciples. The primary differece is how log the light is stored. As soo as you take explaatio your drawig out from uder the black light, it stops glowig. 2 dup Stack of ordiary paper UV crayos optics 1 zip-lock bag i optics 1 box 1 optics 1 2 optics 1 desk lamp with UV CF bulb lights box 3 lights 4 tips darkess

24 Goig for a Spi Part 1: Stad o the platform. Hold the bicycle wheel upright by its two hadles ad have someoe get it spiig for you. Slowly, tip the wheel to oe side. What do you feel? What happes to you? Tip the wheel back. What happes? Part 2: Now sit o the platform with oe weight i each had i your lap. Have someoe give you a getle spi. Now raise your hads, with the weights i them, away from your body slowly. What happes? What happes whe you put your hads back 2i your lap? dup Goig for a Spi -- Explaatio Both of these activities deped o coservatio of agular mometum. Agular mometum is a combiatio of your shape ad your spi. I part 1, while you have o spi, the wheel does have spi. Whe you chage the directio it is spiig, you have to spi the opposite way to balace thigs out. I part 2, chagig your shape forces a chage i your spi. explaatio Bicycle wheel with hadles rotatioal motio shelves 1 o box Spiig platform (the cast iro oe is better) rotatioal motio shelves (bottom shelf!) 2 o box Had weights purple for little kids, blue-gree for the rest rotatioal motio shelves 3 heavy stuff 4 tips Have small kids ad the timid sit dow to do this rather tha stadig. For small people who are strog eough to hold the wheel but whose arms are t log eough, have them hold oe hadle with both hads with the axle perpedicular to their body ad the raise the wheel over their heads so the axle is vertical to make themselves spi. darkess

25 Have the Borrowers Stole Your Pellet? Race the pellets through the two copper tubes. What happes? (Have patiece!) Does either pellet stick to the copper pipes? Does either pellet stick to the base holdig the copper pipes? Drop the two side by side over the foam, but ot through pipes. What happes? Hold the gree strip alog oe of the pipes. What do you see whe each pellet falls through that pipe? Compare this to Jumpig Rigs. Have the Borrowers Stole Your Pellet? -- Explaatio Oe of the pellets is a strog maget ad the other is ot. As the maget moves through the copper tube it causes electros i the copper to move i circles aroud the pipe. The movig electros behave like a secod maget, which pushes the first maget back up the tube so that it falls much more slowly. Without the tube, the maget falls the same way the o-maget does. Try it. explaatio 2 dup copper tubes attached to blue blocks mouted o a rig stad slugs stored i capped pipe large gray square of foam with a hole i its middle magetism va de Graaff box 1 2 heavy stuff va de Graaff blue, Ceco rig stad base rig stad bases 3 heavy stuff magetic field imagig film - log gree strip about 1 wide i white box optics 1 4 optics 1 tips Check that pipes are both vertical or the slugs may hag up iside. Uscrew the pipe from its base, thread the foam oto the pipe ad reattach to base. darkess

26 Ivisible Lake Blow bubbles over the opeig to the box ad let them fall ito it. What happes? Compare the behavior of the bubbles before they get ito the box ad after they get ito the box. What makes thigs float? Ivisible Lake -- Explaatio Carbo dioxide is atural ad you exhale it all the time. Usually it makes up a small fractio of the air. At the bottom of the tak there is a layer of air that is almost pure carbo dioxide. Like a boat floatig i water, the bubbles, which weigh less tha the carbo dioxide, float o the layer of carbo dioxide. Evetually the bubbles will freeze ad most of them break the, but a few survive. What happes to the bubbles iside the box over time? What do they look like just before they break? explaatio 2 dup dry ice chemistry freezer 1 oscillatio bubble stuff ad ati-spill bubble cotaiers cooler pocket oscillatio box 2 oscillatio 2 AA batteries optics 1 3 optics 1 small flashlight with tiltig head cooler pocket oscillaito box 4 oscillatio soft-sided cooler to trasport all of the above oscillatio oscillatio tips Set up i the Lights box with oe side of the lid closed. Make sure kids do t touch the dry ice. If they blow ito the cotaier, it will take a while for the carbo dioxide to accumulate. Use the hammer i the tool kit to break up the dry ice if ecessary. A cooler full will usually easily last for 3-4 hours. darkess

27 Jumpig Balls Rub the rabbit fur, fur side dow, o the clear top of the box. Rub fairly fast. What do the balls iside do? What happes if you pick the fur up ad move it over a ball but ot touchig the box? What happes if you put a figer over a ball but ot touchig the box? Jumpig Balls -- Explaatio Rubbig the fur geerates static (like walkig o carpet i the witer). The rubbig moves charges betwee the plastic of the box ad the fur so that both ed up charged. The styrofoam beads become polarized - oe side positively charged ad the other egatively charged. They are attracted to the charged plastic ad jump up to hag from it (because they are very light weight). Touchig the plastic ucharges it where you touch it which causes the balls to move aroud. explaatio What happes if you touch the top of the box with your figer? Do the balls attract or repel each other? 2 dup ~1ft square, 1.5 deep woode box with plexiglas lid taped o ad grey beads iside oscillatios box 1 oscillatio ziploc bag with rabbit fur oscillatios box 2 oscillatio 3 4 tips This works better i dry weather. It ca become too charged so that othig more happes. Try wipig with a had. darkess

28 Jumpig Rigs RINGS MAY BE HOT DO THIS ONLY WITH ADULT SUPERVISION. DO NOT FIDDLE WITH ANY OF THE ELECTRICAL CONNECTIONS. WATCH OUT FOR FALLING RINGS. Fid the dial with umbers aroud it. Tur the dial. What happes to the rigs? Try turig the dial to the same settig at differet speeds. Try turig the dial to differet settigs at the same speed. Try differet rigs. Ca you make a rig hover? Jumpig Rigs -- Explaatio Whe you tur the dial, you sed electros through the gree cord. This makes a electromaget - a maget made from movig electros istead of specially treated iro or other material. This kid of maget ca be tured o ad off. As the maget is tured o ad off, it pushes electros i the alumium rigs aroud the rigs i circles (oe directio for o ad the other for off). The electros push back, but sice the maget is sittig o the table, the maget does t move ad the rigs do. This is like pushig off from the wall of the swimmig pool - you push o the wall ad it does t move ad istead you move explaatio away from the wall. If the dial is at the right settig, the rigs push themselves up just as much as gravity pulls them dow, so they hover. Notice that the rig that does t jump has a break i it. This prevets the electros from goig aroud i circles, so that rig does t jump. Hold a piece or two of broke maget towards where the rigs jump from. What do you feel? 2 dup 3 4 Compare this to Have the Borrowers Stole 2 your Pellet? metal, plastic, ad cut rigs stuff 1 heavy stuff gree electromaget with its cord stuff 2 heavy stuff roud, gree variac power supply stuff 3 heavy stuff broke magets ziploc bag i optics 1 4 optics 1 tips The iro core of the electromaget ca be exteded or retracted. The rigs ca be stored trapped o the core whe it is retracted. Needs a adult to moitor sice it uses 110V with exposed plugs ad coectio ad the rigs ca get hot eough to bur. See photo. darkess

29 Newto s Pedulum Start by makig sure the 5 balls are ot movig. Pull oe ball away from the others ad let it go. What happes? Pull two balls away from the others ad let it go. What happes? Pull three balls away from the others ad let it go. What happes? Newto s Pedulum -- Explaatio This is like boucig balls off the floor. If you drop oe ball, oe ball will come back up to your had. If you drop two balls, you would expect two to bouce back up. I this case the balls i the middle acts like the floor ; they move istead of stayig still like a regular floor though, so the balls come out the other side. explaatio 2 dup Woode cradle with 5 steel balls suspeded mechaics shelves 1 va de Graaff tips See photo. darkess

30 Phatom Ghost Try to pick up the ghost or pig. (Ca you fid where it is hidig?) Look iside the saucer. What are the iside walls made of? Why do you thik you see a ghost o top? What do you thik the ghost o top is made of? Phatom Ghost -- Explaatio The iside of the saucer is made of curved mirrors. The mirrors reflect the light from the plastic ghost to the top to form a ew ghost made out of light. Do you thik this will work with ay object? explaatio 2 dup black flyig-saucer shape mirrored o iside small pig small ghost optics 1 zip-lock bag i optics 1 zip-lock bag i optics 1 1 optics 1 2 optics 1 3 optics 1 4 tips Trasport mirror with top flipped over ad a square of flael betwee two halves. darkess

31 Rattlebacks Set oe of the rattlebacks curved surface dow. Give it a spi? Whe it stops spiig, spi it the other directio. What do you otice? Does it matter which had you use? Try rockig the rattleback. What happes? Now tur the rattleback over, flat side dow, ad put it over the words o this page. What do you otice about the words? What does this tell you about the shape of the Rattleback? Rattlebacks -- Explaatio Now tur the rattleback over, flat side dow, ad put it over the words o this page. What do you otice about the words? explaatio 2 dup Rattleback(s): trasparet plastic, ~3 log, ovalish shape sliced through the middle zip-lock bag i optics 1 1 optics tips Place o a smooth surface for best results. darkess

32 Ruig i Circles (This requires a bit if a kack, so try several times. If you still ca t get it to work, ask a voluteer for help.) Hold the large rig i oe had. Give the colored rigs a good spi with your free had. Assumig oe or more start really spiig, walk the big rig aroud by grabbig its top ad pullig towards you. You do t eed to do this very fast. Try to keep the colored rigs about half way up the far side. Ca you do this with the colored rigs spiig either directio? Do they keep spiig if you do t keep rotatig the rig? Ruig i Circles -- Explaatio Oce the colored rigs are spiig, they wobble like a top or a frisbee. This makes them rub agaist the big rig. The colored rigs keep goig because you keep puttig eergy ito them by liftig them with every rotatio of the big rig. explaatio 2 dup Large steel rig with much smaller colored rigs threaded o it optics 1 1 optics tips darkess

33 Seeig Ifiity Put your head ito the box eough to look ito oe of the mirrors. What do you see? How may of you are there? Getly tilt oe of the mirrors up/dow ad frot/back. What happes to what you see i the mirror? Whe ca you see the most copies of yourself? How is this related to Doppelgagers? Seeig Ifiity -- Explaatio The light i the room bouces off you. Some of it hits oe mirror. The light bouces back off the mirror ad some of it hits the other mirror. Back ad forth the light goes like a edless pig-pog game. Each time some of the light also hits your eyes - this is why you see the images of yourself. explaatio 2 dup square mirrors optics 1 box 1 optics tips Set up i the empty Optics box. Mirrors store i flael sack. See photo. darkess

34 Shrikig Pey Drop a pey iside the box. What happes to it? Is this possible? Tryig to figure out how this works: With the pey iside, tip the box getly frot to back. What happes to the pey? Now tip the box getly upside dow so that the pey disappears agai. Tip the box aroud getly this way ad try to determie the shape of the area the pey ca move aroud i. Look very carefully at the corers of the box ad at the patters there. What do you otice? Shrikig Pey -- Explaatio There are two mirrors ruig diagoally from the back corers of the box to meet at the ceter of the box. You are t seeig the etire iside of the box eve though it looks like you are. explaatio 2 dup a few peies small, rectagular, plastic box with silver fuel iside ad coi slot o top iside box optics 1 1 optics 1 2 optics tips This is a especially good oe to ecourage adults to work o figurig out by tippig the box aroud. darkess

35 Smoke Rigs Flip the switch to o util you see the chamber fill with smoke. Tur the switch back off. Pull the small trigger to release the smoke rigs. How big a smoke rig ca you make? Watch how the smoke rigs fall apart. Smoke Rigs -- Explaatio Pullig the trigger thumps the drum, which seds a smooth puff of air out. The air drags some smoke with it. As smoke comes through yellow hole i the frot, some of it gets caught o the edge ad curls uder, formig the smoke rig. The wid i the room mixes the smoke up so the rig disappears. explaatio 2 dup smoke gu - bulky pistolish, trasparet plastic va de Graaff 1 va de Graaff smoke fluid - had-sized, rectagular, traslucet white, plastic, bottle va de Graaff 2 va de Graaff AA batteries optics 1 3 optics 1 4 tips darkess

36 Stadig Waves There should be a wire loop or a set of thi metal strips attached to a machie to shake them. You ca cotrol how hard ad how fast they are shake by adjustig the left two kobs o the attached sigal geerator (blue box). How fast is the left kob. You ca see how may times per secod they are beig shake o the display scree. If you tur this kob fast, that umber will chage quickly too. If you tur it slowly, the umber will chage slowly. The kob labeled amplitude cotrols how hard they are shake. You probably do t eed to adjust this kob. Try adjustig the left kob util you see iterestig patters. Stadig Waves -- Explaatio The iterestig patters show up at resoace. This is the same thigs as what you do automatically whe you push someoe else i a swig at the park: you oly push forwards as they start to move forwards otherwise you make them stop istead of makig them go higher. explaatio Ca you get the rig to show three lobes? How may differet ways ca you get this to happe? Does the rig always move the same directio it is beig pushed? 2 dup geerator ad its power cord oscillatios shelves or E&M stuff 1 oscillatio osculoop ad oscillator bars oscillatio box 2 oscillatio oscillator oscillatio shelves 3 oscillatio 2 baaa to baaa wires wire rack by door to oscillatio tips The loop works better tha the bars. ~19Hz ad ~78Hz are iterestig for horizotal forcig of vertical loop. A bright light (e.g. the su) reflectig off a atiode will show the trajectory of the wire (a double figure 8 at 78Hz). Put stad o top of geerator to get height to clear table. See photo. darkess

37 Stadig Waves II Getly hold the base of the goblet with oe had. Dip a figer of the other had i the water ad the ru your figer aroud the rim. Experimet with speed ad pressure util you get a soud. Chage the amout of water i the goblet. What happes to the soud? Look at the water carefully while you re makig the goblet rig. What do you see? Stadig Waves II -- Explaatio The iterestig patters show up at resoace. This is the same thigs as what you do automatically whe you push someoe else i a swig at the park: you oly push forwards as they start to move forwards otherwise you make them stop istead of makig them go higher. Your figer sticks ad the slides (stick-slip). Whe it does so at the correct frequecy it sets up a wave i the goblet which i tur sets up a wave i the air which you hear. explaatio 2 dup goblet optics 2 1 optics tips Goblet has foam est ad bubble wrap i the oscillatio box. darkess

38 Step Right Up ad Shake Your Ow Had Stad (or keel) o the tape lie. Get your head cetered i the mirror. Reach your had out toward the mirror as though shakig hads. What happes? Ca you shake hads? Step Right Up ad Shake Your Ow Had -- Explaatio The mirror is a cocave mirror. Cocave meas that the middle is carved out like lookig ito a cave. The poit where your had gets blurry ad chages from beig right-side-up to up-side-dow is the focal poit which defies how curved the mirror is. explaatio 2 dup large cocave mirror with its ow base top of optics shelves 1 o box tips Do t take this out i the wid it ca crack the moutig as well as tip over. Still eeds a box - or just reiforce the curret box ad use it. darkess

39 Tadem Swigs Getly hold oe hagig rod still as it hags straight dow. Equally getly, pull the other rod back a little ad let it go of both rods. Do ot let the rods hit each other. What happes? Watch for a while ad see if you ca see a patter. Try movig the elastic bad up or dow o the rods. What happes ow whe you swig oe rod? What happes if you tighte or loose the bad? Now try movig the big washers so they do t match o the two rods if they did before or so they do match if they did t before. To do this twist the wig uts to loose them ad the adjust oe up or dow the tighte the other agaist it with the washers cetered. What happes ow if you swig oe rod? 2 dup Tadem Swigs -- Explaatio The swigig mass pulls o the other mass through the elastic bad. The other mass pulls back, slowig the first mass dow. Evetually the secod mass will be swigig ad the first mass will be at rest. The the process repeats itself. The positio ad tightess of the bad cotrols how strogly the swigig rod pulls o the o-swigig oe. The locatio of the washers cotrols the time it takes the rod to make oe swig - if the two rods are t matched well it s like pushig someoe o a swig at the wrog time. explaatio coupled pedulum assembly - woode frame with metal rods uder PPLAY table 1 o box tips darkess

40 Taz s Tops They spi like crazy, just like the Tasmaia devil i cartoos. If you spi these tops quickly eough, they will tip themselves over ad the stad back up agai -- up-side-dow. Start with a top roud ed dow ad give it a good spi. If you re lucky it will tur upside dow without ruig off the edge of the table or ito somethig first. Taz s Tops -- Explaatio Have you ever tried to throw a Frisbee up-side-dow? If you have, you kow it does t spi very well. Some thigs, based o their shape, have a preferred directio to spi. These tops like to spi lookig like mushrooms -- so much so that they will stad o their heads to do so. If you d like a more detailed explaatio, ask oe of the voluteers explaatio 2 dup tops: small sliced-off spheres with dowel rods zip-lock bag i optics 1 1 optics 1 sake to corral the tops (purple with stars) va de Graaff box 2 va de Graaff 3 4 tips The smoother the surface these spi o, the better. darkess

41 Tilt-a-Reed Pick up oe tube ad tilt it. What happes? Pick up a differet tube ad tilt it. Are the results the same or differet? Try tiltig 2 or more tubes at the same time. Ca you chage how loud the soud is? Ca you chage the pitch other tha by usig a differet tube? Look iside the tube? What ca you see? How do you thik this works? Tilt-a-Reed -- Explaatio Each tube has a thi sheet of material (the reed) iside stretched across a rig. Whe you tilt the tube, the rig slides dow the tube. This pushes air past the thi sheet (like wavig your hads i the air to dry them) which makes the sheet vibrate. The tube makes it easier to hear this vibratio, which is fast eough that humas hear a pitch rather tha a rattle. explaatio 2 dup plastic tubes over a foot log music shelves 1 optics tips darkess

42 va de Graaff Use plastic grabber to maipulate the small ball o a stalk. va de Graaff -- Explaatio Electrostatic repulsio of like charges. Tur o ad off with small ball touchig large ball. Tur off to set thigs o sphere. Move small ball away to see small lightig. Move away ad towards slowly to make bat flap wigs. If day is dry, bat may be iduced to fly off. explaatio Tape pompom to top of big sphere. Move small sphere away ad watch hair stad o ed. Stack alumium pas o top of large sphere. 2 Pull small sphere away slowly ad watch pas float up ad dupfly away va de Graaff woode shelves 1 va de Graaff fur bat, blue pompom woode shelves ear va de Graaff 2 va de Graaff small alumium pie pas woode shelves ear va de Graaff 3 va de Graaff plastic grabber woode shelves w/ va de Graaff 4 va de Graaff high voltage sig woode shelves w/ va de Graaff va de Graaff tips This is a demo lest kids get shocked. darkess

43 Vaishig Bulb Hold the white butto dow util the light bulb lights up. Release the butto ad getly uscrew the light bulb. Look through the eye hole. Hold dow the white butto. Do you see a light bulb? What happes if move your head aroud? Put the bulb back i ad look through the eye hole while holdig the butto dow. Does it look the same as before? See if you ca figure out how you ca see somethig that is t there. Vaishig Bulb -- Explaatio There is a secod bulb mouted up-side-dow directly below the visible bulb. Whe you look through the eye hole, you see the reflectio of the secod bulb i the mirror exactly where the first bulb ought to be. If you move your head aroud, the positioig is t quite so good. explaatio 2 dup Woode cube w/ 2 sides ope ad 2 light sockets optics shelves 1 cocave mirror o top of optics shelves 2 two idetical light bulbs light sources o optics shelves 3 4 tips Needs to be rebuilt before it ca be used. This eeds to be adjusted for both height ad distace so that the effect works. The viewer s height matters too (?). darkess

44 What Color is Your Shadow? DON T LOOK DIRECTLY AT THE LIGHTS FOR LONG. DON T TOUCH THE LIGHTS OR TOUCH THINGS TO THEM. Stad with a had very close to the wall. Move your had aroud ad look at the shadows it creates. How may colors ca you get? Try chagig the space betwee your figers ad the distace of your had from the wall. What Color is Your Shadow? -- Explaatio White light is made up of may colors. Here we make white light with just three colors: red, gree, ad blue. Whe you stad i frot of oe color, you block this color from reachig the wall so your shadow is a combiatio of the two remaiig colors. How may differet colors ca you make o the wall? Try stadig closer to the lights ad i frot of each oe. What color shadows does this produce? explaatio 2 dup red, blue, ad gree bulbs mouted o bases (alumium reflectors) lights box 1 lights tips Set up the lamps so the ceter of the field is as close to white as possible. These get quite hot, so try to place them out of the traffic path. See photo. darkess

45 ZZ ew experimets magic wad (maget through coil) had geerator cor starch ad water tape tree for polarizers lucite force to squeeze betwee polarizers ramp versio of ewto s pedulum revise bug s eye view to use two leses chatter stoes ZZ ew experimets -- Explaatio explaatio 2 dup tips darkess

46 ZZ Stuff ot to forget ZZ Stuff ot to forget -- Explaatio explaatio 2 dup tool kit (black plastic box), otebook PPLAY stuff 1 o box 1 white extesio cord - 2 wire lights box 2 lights 1 orage ad 3 white extesio cords - 3 wire, 3 plugs lights box 3 lights 1 white power strip lights box 4 lights blue tape, electic tape tape shelf heavy stuff tips darkess