Monday, June 25, 2012

Happy Birthday Series: Part 1 Science Edition

Okay, I know that many people feel that kids' birthdays have gotten out of hand, and while you aren't going to see us on some "My Sweet 16" type reality show any time soon, in our family we like to really do up the birthday parties.  It's not about spending a lot of money, or getting lots of presents, it's more about celebrating these childhood years.  Soon enough they'll be teenagers who'd just assume I pay for the pizza and scram; so, I pour plenty of time and effort into each party.

I really enjoy home parties. It probably is because that's how I grew up, but I just like memories being created at home (or at Mimi and Grandpa's as we often do).  Parties at jump places, pizza arcades, and such are fun but sometimes they just feel a bit generic.

Each birthday around here starts with a theme.  This year, my oldest son, Brooks, turned 7.  In the past we've done themes such as basketball, Star Wars, Superheros, safari, Bob the Builder, etc.  This year I just knew he was going to pick a football party.  However, I timidly suggested a Mad Science theme and was thrilled when he said yes! Theme chosen, I picked a color scheme and moved forward.  Here's how it all went down:


The hand-assembled invitaions (made easier thanks to my mom and her Cricut!)


As they arrived, each child was given a white bag to use to hold their experiments.  The experiments were set up in stations manned by helpful friends and family. We encouraged the kids to go to which ever they wanted in whatever order they chose--this kept things more spread out.



This was the slime making table.


Insta-Snow from Steve Spangler Science was so, so cool! Easy to do but made a huge impact on the kids. You can buy it on-line from several sources.



The kids had fun makng their own "lava lamps" here. I did realize too late that I should have gotten an actual lava lamp to show them since none of them really knew what one was!



I ordered these geodes from Oriental Trading Company. They were really neat and the kids LOVED them even more than I anticipated. I would recommend ordering more than you need because some proved impossible to break.

 
 


In my opinion, the coolest thing we did was Naked Eggs.  Because these take a few days to prepare, I made them all ahead if time and had them on display for the kids to touch and look at and then take home.  On another table we had various insects in little jars with magnifying glass lids; these were displayed with Brooks's academic fair project for which he had taken various pictures with his computer microscope and then made a lift-the flap style guess what this picture is game.




What can I say, kids + exploding Diet Coke= chaos. The Diet Coke/Mentos geyser was really a blast (pun intended). We did it several times using the different tips in the geyser tube kit--you can order it on-line, but I later saw them at Hobby Lobby as well. Just a word of caution: The unexploded portion of the Diet Coke quickly became used ina Diet Coke battle of sorts--it gets messy. That, by the way, is the reason for Diet--it's less sticky.


Up until this point, I will take credit, but not for this one. My husband declared that there was going to be a volcano at the party. I agreed and began talking paper mache and baking soda and vinegar. He said no--he wanted a big, giant volcano. I told him it was his baby--count me out. Well, in collaboration with his dad, I will say that they produced one heck of a volcano. It had recorded eruption sounds, popping streamers, dry ice steam, and spewing "lava" made of jello. It was a huge hit. Come to think of it, I think it deserves a video segment. Watch the fun:
video

We also had fun with the food. A chocoalte fountain was filled with toxic slime (white chocolate and food coloring) for dipping pretzels and fruit. Petri dishes were filled with specimens (gummy critters) and green jello Dishes of gummy worms sat ready for disection. Peanut Butter in celery topped with raisons were "Ants on a Log". I ordered a set of cookie cutters from ebay and used the beaker one to cut PB&J sandwiches. Water, labeled H2O was available to drink.

The next activity took some advance planning and got messier than I anticipated but it was worth it. I split the kids into pairs and they made their own ice cream to go along with the cake. It really tasted good and even the adults were impressed.


The party favors were a science book that I got at the 99 cent store, a sparkly green test tube full of nerds, and a booklet giving instructions for each experiment and explaining the "why" behind each one. I found the test tubes without lids at the Dollar Tree (they were supposed to be shot glasses; believe me I got a weird look when I said they were for my 7 year old's party). I also got coordinating plastic shot glasses there which were the perfect size for the Insta-Snow experiment. The test tubes with lids, petri dishes and plastic beakers were purchased on-line. 

I'm going to be honest; this was the most exhausting party to plan, prepare for, and execute. It required help from our families and a whole bunch of work. But it was totally worth it. More than one child told me it was, "the best party ever." And more importantly, Brooks was happy, and we created a wonderful childhood memory as we celebrated my first baby boy.



I'm going to post my entire party planning list with the recipes I used and the explanations I published in the party favor book.  Please understand that I gathered this info and ideas from all over the place--internet, books, experience. Just click on see more to view the entire document:

BROOKS’S SCIENCE PARTY
ACTIVITIES: & Shopping List
·         Slime Making
1)      Borax- 4 cups
2)      Clear Elmer’s Glue- 30 tbsp
3)      Food Coloring
4)      Clear cups and plastic spoons
·         Lava Lamp Making
1)      Empty Water Bottles
2)      Vegetable Oil- 360 oz/45 cups
3)      Food Coloring
4)      Alka-Seltzer- 30 tablets
·         Geode Breaking
1)      30 socks
2)      A few hammers
·         Play with Naked Eggs
1)      3 dz eggs
2)      Clear Cups in Plastic Bags
·         Mentos Geyser
1)      5 tubes of mentos
2)      5 2 liters of diet coke
·         Insta-snow
1)      Insta-Snow
2)      Clear Cups
3)      Bathroom cups
DISPLAY:
·         Naked Eggs
·         Bugs in Magnifying Jars
·         Microscope pictures (fair project)
FOOD/DRINK:
·         Chocolate Fountain: White Chocolate, Food Coloring, Oil
·         Strawberries, Cherries, Bannannas
·         Marshmallows
·         Pretzels
·         Petri Dish Bugs: Jello, Candy bugs
·         Colored Celery ants on a log: Celery, food coloring, peanut butter, raisins
·         Ice Cream in a bag: 60 tbsp sugar, 30 c half and half, 15 tsp vanilla, 15 cup kosher salt, 15 gallon ice, 60 pint ziplocks, 30 gallon ziplocks
·         Cake:
·         Beaker shaped Finger Sandwiches-PB & J
·         Water
·         Capri Suns
Ice Cream in a Bag
Ingredients
2 tablespoons sugar
1 cup half and half
1/2 teaspoon vanilla extract
1/2 cup salt (The bigger the granules, the better. Kosher or rock salt works best, but table salt is fine.)
Ice cubes (enough to fill each gallon-size bag about half full)
1 pint-size ziplock bag
1 gallon-size ziplock bag
Instructions
1. Combine the sugar, half and half, and vanilla extract in the pint-size bag and seal it tightly.
2. Place the salt and ice in the gallon-size bag, then place the sealed smaller bag inside as well. Seal the larger bag. Now shake the bags until the mixture hardens (about 5 minutes). Feel the small bag to determine when it's done.
3 .Take the smaller bag out of the larger one, add mix-ins, and eat the ice cream right out of the bag. Easy cleanup too!
Serves 1.
How Does it Work?
Salt lowers the freezing point of the ice and creates an extra-cold brine that absorbs heat from the milk mixture, causing the mixture to freeze.
Why shake the bag?
The motion creates smoother ice cream by breaking up large ice crystals and allows the ice cream to freeze uniformly.




Slime (Fake Snot) Making
What You Need:
•Borax Powder
•Elmer's Glue
•Water
•Food Coloring
•Measuring Cups
•Baggies or Bowls
Directions:
1. Stir 1/8 cup borax into 500 ml warm water. It's okay if some borax remains undissolved. Allow solution to cool to room temperature.
2 .In a separate container, stir 2 spoonfuls of glue into 3 spoonfuls of water. White glue will give you opaque snot (more booger than snot); glue gel will produce you translucent slimy snot.
3 .Stir a couple of drops of food coloring into the glue mixture.
4 .Add a spoonful of the borax solution to the glue mixture. Stir (if in a bowl) or squish (if in a baggie).
5 .Have fun with your snot!
Tips:
1 .Elmer's glue is a non-toxic, water-based white glue or a non-toxic blue or clear gel. Another brand may be substituted.
2 .A little yellow food coloring could be added for that extra sickly touch.
3 .Don't eat or inhale the snot. Borax isn't particularly toxic, but isn't good for you either.
4 .Borax is found in the household cleaner or laundry section of the store. It's commonly used as a detergent booster.
5. Wash your hands after playing with your snot.
How does it work?
The mixture of Elmer’s Glue with Borax and water produces a putty-like material called a polymer. In simplest terms, a polymer is a long chain of molecules. You can use the example of cooking spaghetti to better understand why this polymer behaves in the way it does. When a pile of freshly cooked spaghetti comes out of the hot water and into the bowl, the strands flow like a liquid from the pan to the bowl. This is because the spaghetti strands are slippery and slide over one another. After a while, the water drains off of the pasta and the strands start to stick together. The spaghetti takes on a rubbery texture. Wait a little while longer for all of the water to evaporate and the pile of spaghetti turns into a solid mass -- drop it on the floor and watch it bounce.
Many natural and synthetic polymers behave in a similar manner. Polymers are made out of long strands of molecules like spaghetti. If the long molecules slide past each other easily, then the substance acts like a liquid because the molecules flow. If the molecules stick together at a few places along the strand, then the substance behaves like a rubbery solid called an elastomer. Borax is the compound that is responsible for hooking the glue’s molecules together to form the putty-like material. There are several different methods for making this putty-like material.  http://www.stevespanglerscience.com/experiment/glue-borax-gak

Lava Lamps
Materials
• Clean, plastic soda bottle, glass, jar, or Baby Soda Bottle Test Tube
• Soda bottle cap
• Vegetable oil (the cheaper the better)
• Food coloring
• Alka-Seltzer tablet or Fizzy Tablets
• Flashlight
• Water
Directions
1. Fill the bottle 3/4 full with vegetable oil.
2. Fill the rest of the bottle with water (almost to the top but not overflowing).
3. Add about 10 drops of food coloring. Be sure to make the water fairly dark in color. Notice that the food coloring only colors the water and not the oil. Hmmm...
4. Divide the Alka-Seltzer tablet into 8 pieces.
5. Drop one of the tiny pieces of Alka-Seltzer into the oil and water mixture. Watch what happens. When the bubbling stops, add another chunk of Alka-Seltzer. It’s just like a lava lamp!
6. If you want to make it even more "lave-like," put your bottle on a flashlight and turn the room lights off.
7. When you have used up all of the Alka-Seltzer and the bubbling has completely stopped, screw on the soda bottle cap. Tip the bottle back and forth and watch a wave appear. The tiny droplets of liquid join together to make one big lava-like blob.
 How does it work?
First of all, you confirmed what you already knew... oil and water do not mix. The molecules of water do not like to mix with the molecules of oil. Even if you try to shake up the bottle, the oil breaks up into small little drops, but the oil doesn’t mix with the water. Also, food coloring only mixes with water. It does not color the oil.
When you pour the water into the bottle with the oil, the water sinks to the bottom and the oil floats to the top. This is the same as when oil from a ship spills in the ocean. The oil floats on top of the water. Oil floats on the surface because water is heavier than oil. Scientists say that the water is more dense than the oil.
Here’s the surprising part... The Alka-Seltzer tablet reacts with the water to make tiny bubbles of carbon dioxide gas. These bubbles attach themselves to the blobs of colored water and cause them to float to the surface. When the bubbles pop, the color blobs sink back to the bottom of the bottle.  http://www.stevespanglerscience.com/experiment/bubbling-lava-lamp


Geodes
What are Geodes?
Geodes are like the Tootsie Roll Pop of the geology world because underneath the hard exterior lies a surprise center!
Hollow Rocks
So, let’s start at the beginning: how do you get a hollow rock with lots of sparkling crystals inside? First you need a hollow rock. Geodes start their lives as a hollow bubble inside a layer of rock. The bubble could be from air inside explosive volcanic rock or it could come from the hollow remains of animal burrows or tree roots.
What About The Crystals?
When these rocks form from air bubbles inside of volcanic rock it is pretty easy to picture. Think about the small air bubbles you see in pumice. Now, imagine just one of those bubbles completely surrounded by black or red volcanic rock. As rain pelts down on the hot bubble, the chemicals in the rock are slowly released into the water. Some of the water soaks through the hard, rocky outside of the bubble and is trapped for a moment on the inside. As the mineral-rich water moves on through the bubble, tiny crystals are left behind, clinging to the sides of the bubble. Millions of years pass while this in and out flow of water gradually builds crystals inside the empty space. The crystal formations might become large single crystals or tightly packed micro-crystals, so small that you can’t even distinguish one from another. An Animal‘s Home
Let’s check out the development of our animal burrow bubble… Long after the animal has moved on or the tree has died and its roots have rotted away, the sediments that surrounded the hollow are being covered up by layers and layers of sediment hundreds of feet think. Eventually the weight of these layers has caused the sediments to turn into rock: sedimentary rock. Just like our volcanic bubble, this animal burrow bubble is host to mineral-filled water flowing in and out through the hollow space. And just like the volcanic bubble, a wide variety of crystals are taking shape inside the animal’s former home.
Time Marches On
Fast forward to modern times. The water-soaked land where our bubbles began has become a vast desert where wind howls and the sun beats down. The ground, covered by rocks and scrubby brush yields up unusually shaped rocks. Today, you’ve found a good field of them and have three nearly-round specimens to crack open when you get home.
All Geodes Are Not Created Equal
The first one is quite hollow but for a nice layer of medium-sized blue crystals. These dugway geodes have bands of blue and pink. The colors come from the different minerals that flowed through the bubble so many millions of years ago. Another specimen is nearly solid all the way through. The microcrystals have formed wide bands of different colors and the tiny opening at the center has a thin ring of pointed crystals. Yet another is completely filled with solid rings of browns, reds and pinks. So, you’ve really found two geodes and one nodule. Nodule is the name for these round forms when they are filled solid.
They Come In Colors
As each specimen offers up a different interior, you wonder, “What causes all the colors?” So you head to the computer and you’ve arrived at this page, so I’ll need to tell you.
Trace Elements
Remember the mineral-rich waters that flowed through the bubbles forming crystals inside? There is a variety of elements that can be present in mineral water. It would all depend on the type of rocks the water passed over and through on its way to the geode. Rocks contain iron, magnesium, sulfur or a host of other elements.
Now, think about the variation that can occur in terms of saturation amounts of the different minerals. You can imagine that the different rocks forming from all these variations could be limitless. But there is some consistency that makes it easier for us.
Quartz, Calcite, Or What?
Most geodes have interiors made of either quartz or calcite. Quartz crystals are silicates. Silicates are the most common mineral in the crust of the earth. Over 90% of the minerals present in earth’s crust are silicates. With this said, you can imagine that silicates are a pretty big group with lots of variation in terms of specific chemical composition.
Calcite’s main ingredient is calcium carbonate CaCO2: dissolved calcium and carbon with some of the oxygen from the water thrown in.
Small variations Can Make A Big Difference
Now, add in a trace of iron or magnesium or copper and, voila, you have color variation. Magnesium traces in calcite forms a nice pink dolomite layer, while magnesium in silicate accounts for the purples of amethyst.
Heat Can Change It
Now if your geode was close to a lot of heat, that could change the color, too. An amethyst that gets a lot of heat loses its purple color and becomes a soft yellow or citrine. You can see why there are so many color possibilities.
A Day In The Life
So, that little geode you’re holding has had quite a journey getting to your hand. Treasure it for its beauty, but also for its history and the complex composition of minerals that made it. You’re holding millions of years of work in your hand…enjoy touching the miracle of our earth’s creation. http://www.rocksandminerals4u.com/geodes.html


Insta-Snow
How does it work?
Insta-Snow® is actually derived from the superabsorbent polymer found in baby diapers. The only difference (and it’s a big one) is that the Insta-Snow polymer not only absorbs water but the long chains of molecules swell to an enormous size. The polymer soaks up water using the process of osmosis (water molecules pass through a barrier from one side to the other). When water comes in contact with the polymer, it moves from outside the polymer to the inside and causes it to swell. The polymer chains have an elastic quality, but they can stretch only so far and hold just so much water.
 The Insta-Snow reaction is a great example of a physical reaction - a reaction where the substance itself does not change. When an ice cube melts, a physical reaction takes place where the solid ice turns into a liquid, but the substance (water) never changes - it's still water! However, in a chemical reaction, a new substance is formed and energy is either given off or absorbed.
 If you think of the Insta-Snow powder as millions of tiny sponges, it's easy to see that neither the Insta-Snow powder or the water was changed. If you allow the water to evaporate, the Insta-Snow powder dries out and returns to its previous state, ready to be used again. http://www.stevespanglerscience.com/experiment/insta-snow-polymer


Mentos Geyser
What you Need:
• A roll or box of Mentos® mints
• 2-liter bottle of diet soda (diet or regular soda will work, but diet soda is not as sticky)
• Piece of paper (or for a perfect drop every time, check out Steve Spangler's Geyser Tube)
1. This activity is probably best done outside in the middle of an abandoned field, or better yet, on a huge lawn.
2. Carefully open the bottle of soda. Position the bottle on the ground so that it will not tip over.
3. Unwrap the whole roll of Mentos. The goal is to drop all of the Mentos into the bottle of soda at the same time (which is trickier than it looks). One method for doing this is to roll a piece of paper into a tube just big enough to hold the loose Mentos. You'll want to be able to position the tube directly over the mouth of the bottle so that all of the candies drop into the bottle at the same time.
4. Don't drop them into the bottle just yet! Warn the spectators to stand back. Okay, you're going to drop all of the Mentos into the bottle at the same time and then get truckin' (move out of the way... so long... bye- bye... hasta la vista!)
5. It's just like fireworks on the 4th of July. The spectators erupt, of course, in a chorus of ooohs and ahhhs. Someone yells out, "Do it again" and you do.
 The Geyser Tube Variation
 1. You’ll need a 2-liter bottle of diet soda (diet doesn’t make a sticky mess) and an outdoor location for your geyser. Select a flat surface on the lawn or driveway to place the bottle.
2. Start by tying one end of the string to the trigger pin (the string might already be attached to the pin) on the Geyser Tube.
3. Open the bottle of soda and attach the Geyser Tube. Put the trigger pin into the hole at the base of the Geyser Tube.
4. Twist off the top cap on the Geyser Tube and drop 7 MENTOS® candies into the tube. The trigger pin will keep the candy from falling into the soda before you’re ready. Replace the twist-on cap.
5. Warn everyone to stand back. Countdown… 3-2-1… and pull the trigger. The MENTOS will drop and the soda will go flying into the air!
6. Pour out the remaining soda and take a look at the MENTOS®. You can see where the soda has eaten away at the surface of the candy. No need to waste the candy… they still taste great.
 How does it work?
Here's the question of the day... Why does mixing Mentos with soda produce this incredible eruption? You should know that there is considerable debate over how and why this works. While we offer the most probable explanations below, we also understand and admit that other explanations could be possible... and we welcome your thoughts.
 As you probably know, soda pop is basically sugar (or diet sweetener), flavoring, water, and preservatives. The thing that makes soda bubbly is invisible carbon dioxide gas, which is pumped into bottles at the bottling factory using tons of pressure. Until you open the bottle and pour a glass of soda, the gas mostly stays suspended in the liquid and cannot expand to form more bubbles, which gases naturally do.
 But there's more... If you shake the bottle and then open it, the gas is released from the protective hold of the water molecules and escapes with a whoosh, taking some of the soda along with it. What other ways can you cause the gas to escape? Just drop something into a glass of soda and notice how bubbles immediately form on the surface of the object. For example, adding salt to soda causes it to foam up because thousands of little bubbles form on the surface of each grain of salt. Many scientists, including Lee Marek, claim that the Mentos phenomenon is a physical reaction, not a chemical one.
 Water molecules strongly attract each other, linking together to form a tight mesh around each bubble of carbon dioxide gas in the soda. In order to form a new bubble, or even to expand a bubble that has already formed, water molecules must push away from each other. It takes extra energy to break this "surface tension." In other words, water "resists" the expansion of bubbles in the soda.
When you drop the Mentos into the soda, the gelatin and gum arabic from the dissolving candy break the surface tension. This disrupts the water mesh, so that it takes less work to expand and form new bubbles. Each Mentos candy has thousands of tiny pits all over the surface. These tiny pits are called nucleation sites - perfect places for carbon dioxide bubbles to form. As soon as the Mentos hit the soda, bubbles form all over the surface of the candy. Couple this with the fact that the Mentos candies are heavy and sink to the bottom of the bottle and you've got a double-whammy. When all this gas is released, it literally pushes all of the liquid up and out of the bottle in an incredible soda blast. You can see a similar effect when potatoes or pasta are lowered into a pot of boiling water. The water will sometimes boil over because organic materials that leach out of the cooking potatoes or pasta disrupt the tight mesh of water molecules at the surface of the water, making it easier for bubbles and foam to form.
When a scoop of ice cream is added to root beer, the float foams over for essentially the same reason. The surface tension of the root beer is lowered by gums and proteins from the melting ice cream, and the CO2 bubbles expand and release easily, creating a beautiful foam on top.
 Next question... Why should you use diet Coke or diet Pepsi? The simple answer is that diet soda just works better than regular soda. Some people speculate that it has something to do with the artificial sweetener, but the verdict is still out. More importantly, diet soda does not leave a sticky mess to have to clean up. Hey, that's important. http://www.stevespanglerscience.com/experiment/original-mentos-diet-coke-geyser


Naked Egg
What Do I Need? .
• a few eggs  
• white vinegar
• a container big enough to hold all your eggs and a cover for the container
• a big spoon
 What Do I Do? 
 Here’s how you dissolve the shell from your eggs:
 1. Place your eggs in the container so that they are not touching.   
 2. Add enough vinegar to cover the eggs. Notice that bubbles form on the eggs. Cover the container, put it in the refrigerator, and let the eggs sit in the vinegar for 24 hours.
 3. Use your big spoon to scoop the eggs out of the vinegar. Be careful—since the eggshell has been dissolving, the egg membrane may be the only thing holding the egg together. The membrane is not as durable as the shell.
4. Carefully dump out the vinegar. Put the eggs back in the container and cover them with fresh vinegar. Leave the eggs in the refrigerator for another 24 hours. 
5. Scoop the eggs out again and rinse them carefully. You might have to rub gently to get all the shell off.  If any of the membranes have broken, letting the egg ooze out, throw those eggs away. 
6. When you’re done, you’ll have an egg without a shell. It looks like an egg, but it’s translucent—and the membrane flexes when you squeeze it. Very cool! 
 What’s Going On?  
When you submerge an egg in vinegar, the shell dissolves. Vinegar contains acetic acid, which breaks apart the solid calcium carbonate crystals that make up the eggshell into their calcium and carbonate parts. The calcium ions float free (calcium ions are atoms that are missing electrons), while the carbonate goes to make carbon dioxide—the bubbles that you see.
Things to do with Naked Eggs
What Do I Need? .
• at least 2 naked eggs  
• containers large enough to hold a single egg and some liquid (coffee mugs or tumblers work fine)
• corn syrup  
• water
• a big spoon      
What Do I Do? 
1. Put one of your shell-less eggs into a small container and add enough corn syrup to cover the egg. Put another egg in a small container and add enough water to cover the egg. Put both eggs in your refrigerator for 24 hours.
2. After 24 hours, take a look at your eggs. What’s happened?
 What’s Going On?  
The egg that was in the water is plump and firm. The egg that was in the corn syrup is shriveled and flabby.
After you dissolve the eggshell, the egg is surrounded by a membrane. (Actually, it’s two membranes, but they are held tightly together.) This membrane is selectively permeable—which means it lets some molecules move through it and blocks other molecules.
Water moves through the membrane easily. Bigger molecules—like the sugar molecules in the corn syrup—don’t pass through the membrane.
When you put a naked egg in corn syrup, you are creating a situation where the egg membrane separates two solutions with different concentrations of water. The egg white is about 90% water; corn syrup is about 25% water. In this situation, random movements of water molecules cause them to move from the side of the membrane where they are more abundant to the side where they are less abundant. So water migrates from inside the egg to outside the egg, leaving the egg limp and flabby.
 What Else Can I Try? .
• Can you think of a way to take that flabby egg and make it plump again? Here’s what we did.
Experiment with putting naked eggs into other solutions. What happens if you put the egg into water colored with food coloring? Or salty water? Experiment and see. Carefully lift the flabby egg from the corn syrup and place it into a container of water. Leave the egg in the water for 24 hours. The water will migrate from the side of the membrane where water molecules are abundant (outside the egg) to the side where water molecules are less abundant. After 24 hours, the egg will be plump again.







1 comment:

makesnowmagic.com said...

Thanks for writing, I very much liked your newest post. I think you should post more frequently. you evidently have natural ability for blogging! Now you can have instant snow anywhere on demand even where it never snows, Kwik-Snowc an make artificial snow or fake snow even in the middle of the desert.

Regards,
snow magic