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updated:100107 GJGjr

Light Soda ( Density)

Be sure that both of the cans of soda are the same brand. Since this is a scientific investigation, we want to control the variables .
What is a variable?
It is something that changes. For example, if you were comparing a can of regular Coke with a can of diet lemonade, you would have several variables. Besides the fact that one has sugar and the other has artificial sweeteners, one is carbonated, while the other is not. Also, there is a big difference between the recipe for Coke and the recipe for lemonade. If you found a difference in the properties of the two drinks, you might not know whether the difference was due to the sweetener, the carbonation, or the recipe. Controlling the variables is very important in science.
The regular soda sinks, while the diet soda floats.
What is the difference?
Both cans are the same size, but one floats and one sinks. The contents of the regular soda must be heavier than the contents off the diet soda.
The variable that we are looking at is the sugar and artificial sweetener. Is sugar that much heavier than aspartame, which is the most commonly used diet sweetener? No, there is not enough difference between the two to cause one can to sink and the other to float. The clue to the difference can be found by looking at the sweetness of the two chemicals. Aspartame is more than one hundred times sweeter than sugar. That means that if you want the two cans of soda to have the same sweetness, you must put one hundred times as much sugar in the regular soda. Adding that much more sweetener makes the difference between floating and sinking .
To get an idea of how more sugar is used, look at the ingredient list on each can. The ingredients are listed in order by amount, with the most abundant ingredient first. Sucrose and high fructose corn syrup are both sugars. Even dividing the sugar into these two groups, you will still see both near the top of the list for any regular soda. Compare that with where aspartame is listed on the diet drink. If you are using a cola, you will notice that the sugar comes before the caramel coloring and that the aspartame comes after it. It varies from brand to brand, but some use more than 400 times as much sugar.

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Ice Race

(Surface Area)

The water in the wide container froze much faster. Why? Even though they both have the same amount of water, they are in very different shapes. The water in the wide container is much more spread out. It has a much larger surface. The surface is where the heat is transferred, so the more surface area, the faster the heat will be transferred and the faster the water will freeze.

You can see the same thing in reverse. Let the cup and the wide container stay in the freezer overnight, to be sure they are both well frozen. Remove them and place them on the table. Wait and check them periodically, to see which one melts first. Which do you think it will be? Right! The wide container melts faster, again because it has more surface area.

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Hot Air Bottle (Thermal Conductivity)

When you put the bottle into the hot water, the air in the bottle gets warmer. As it warms up, the molecules move around more energetically. The molecules bounce against the bottle and the water with more force. This forces some of the air out of the bottle. As the air gets warmer and warmer, the air in the bottle pushes outwards more and more, causing more and more bubbles to come from the bottle.
When the air in the bottle had expanded all it is going to, you put the cap on the bottle and removed it from the water. At that point, the air in the bottle began to cool. The molecules moved less energetically, causing the air to exert less force on the sides of the bottle. The stronger pressure on the outside of the bottle crushes it inwards.
You can take this experiment a step farther by using a balloon. Put the balloon over the mouth of the bottle before you put it into the hot water. As the air heats up, it will inflate the balloon. Then remove the balloon to equalize the pressure. Put it back on the bottle and then remove it from the water. Now as the air in the bottle cools, it will exert less force and the stronger pressure on the outside will force the balloon into the bottle. Keep playing and you can discover all sorts of things, as well as having some fun.

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Picking up an Ice Cube with a String
(Freezing Point)

Lift up on the string, and you should find that the string has frozen to the ice. What happened?
Pure water freezes at 32 degrees F. Adding salt lowers its freezing point, allowing it to be a liquid when it is colder than 32 degrees. Making the change from solid to liquid requires energy. The atoms in the liquid are moving much more than the atoms in the solid. That movement requires energy, so the melting ice absorbs heat from the water around it. That chills the water to the point where it will freeze, sticking the string to the ice cube.

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Egg Bubbles (Thermal Conductivity)

You should see one or more thin streams of bubbles rising from the egg. The bubbles will continue for quite a long time. If you listen carefully, you may also hear a tiny squeaking sound that sounds almost like a baby chick.
What is happening? If you have ever peeled a boiled egg, you know that there is an air bubble inside the shell. As we have seen in past experiments, when you heat air, it expands and takes up more space. The air bubble inside the egg is expanding as it is heated by the water. It is pushing outwards, and it has to go somewhere.
The streams of bubbles were coming from microscopic holes in the egg shell. Those holes are too small for the liquid part of the egg to flow through, but they let air get in, so the developing chick can breathe. As the air inside the shell expands, it flows out through the tiny holes. If the water is too hot, then the air will expand faster than it can flow through the tiny holes, and the shell will crack. That sometimes happens when you are boiling eggs.
The air forcing its way through the tiny pores sometimes makes a tiny whistling or chirping sound. I tried several eggs, and it did not happen with all of them. The eggs might spoil if you put them back in the refrigerator, so only experiment with eggs that you are ready to eat.

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Scaring Pepper(BOO) (Surface Tension)

Instantly, all of the pepper will rush away from your finger, towards the sides of the bowl. At this point, the magician would go on to the next trick, but the scientist is just getting started. Why does it work? We start with an understanding about water. Water molecules are very sticky. They have a strong attraction to other water molecules. In the center of a glass of water, the molecules are sticking to other water molecules in all directions.
At the surface, there are no water molecules above for them to stick to, so they stick even more to the molecules beside them. All of the water molecules are pulling towards each other, much like a lot of magnets attracting each other. This forms a "skin" at the surface of the water that we call surface tension. This surface tension is strong enough to support insects like the water strider. They actually walk on the surface of the water.
There are ways to break this surface tension. One way is by using soap. A soap molecule will stick to a water molecule, keeping it from sticking to other water molecules. That is what happens when you stick your soapy finger into the water. The water molecules beside your finger suddenly stick to the soap molecules instead of each other. The other water molecules on the surface are still pulling, so it is much like a game of Tug-of-War where one side suddenly lets go of the rope. The water at the edges is still pulling, but the water in the center is not pulling back. The surface molecules and the pepper floating at the surface are all pulled quickly to the sides. It is important to remember that even a tiny bit of soap will cause this to happen, so if you want to let your audience try it themselves, you can't reuse the same bowl, unless you rinse it very well and start with fresh water.

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Lumpy Squishy Liquids (non-Newtonian Fluids)

As long as you keep pressure on it by rubbing it between your hands, it stays solid. Stop rubbing, and it “melts” into a puddle in your palm.
Why does the cornstarch mixture behave like this?
Think of a busy sidewalk. The easiest way to get through a crowd of people is to move slowly and find a path between people. If you just took a running start and headed straight for the crowd of people, you would quickly slam into someone and you wouldn't get very far. This is similar to what happens in the cornstarch mixture. The solid cornstarch acts like a crowd of people. Pressing your finger slowly into the mixture allows the cornstarch to move out of the way, but tapping the mixture quickly doesn't allow the solid cornstarch particles to slide past each other and out of the way of your finger.
We use the term “viscosity” to describe the resistance of a liquid to flow. Water, which has a low viscosity, flows easily. Honey, at room temperature, has a higher viscosity and flows more slowly than water. But if you warm honey up, its viscosity drops, and it flows more easily. Most fluids behave like water and honey, in that their viscosity depends only on temperature. We call such fluids “Newtonian,” since their behavior was first described by Isaac Newton (when he wasn’t discovering the laws of gravity or developing the calculus). The cornstarch mixture you made is called “non-Newtonian” since its viscosity also depends on the force applied to the liquid or how fast an object is moving through the liquid.
Other examples of non-Newtonian fluids include ketchup, silly putty, and quicksand. Quicksand is like the cornstarch mixture: if you struggle to escape quicksand, you apply pressure to it and it becomes hard, making it more difficult to escape. The recommended way to escape quicksand is to slowly move toward solid ground; you might also lie down on it, thus distributing your weight over a wider area and reducing the pressure. Ketchup is the opposite: its viscosity decreases under pressure. That’s why shaking a bottle of ketchup makes it easier to pour.

Disposal: First dilute the cornstarch mixture with plenty of water before pouring it down the drain. Why? What do you think would happen to the semi-solid, semi-liquid form that you prepared if pressure were applied to it by water in the drain? Yes – a plugged drain.

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Rainbow in a Glass (Density)

The amount of sugar dissolved in a liquid affects its density. The blue solution has the most sugar dissolved in it and is therefore the densest. The other solutions are less dense than the blue solution, so they float on top of it. The densities of the solutions should be very close however, and the solutions are miscible,or will mix with each other, so you will see that the layers do not form well defined boundaries as in the first experiment. If done carefully enough, the colors should stay relatively separate from each other.
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Cartesian Diver (Density)

The packet has a small bubble of air trapped in it. When you squeeze the outside of the bottle, you increase the pressure inside the bottle. This will compress the air inside the packet, which changes the overall density of the packet. When the air is compressed enough, the density of the packet will be greater than the density of the water in the bottle, and the packet will sink. When you release the pressure on the outside of the bottle, the air in the packet will expand, increasing the buoyancy of the packet, and the packet will rise to the top. If you are using a clear soy sauce packet, you may even be able to see the size of the air bubble change as you squeeze on the bottle.
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Soft water and suds (Density)

Tap water in many parts of the country contains minerals that can interfere with the cleaning ability of detergents. That's why water softeners are popular in these locations. Water softeners remove these minerals. In this experiment, you will make "hard" water from distilled water, which contains no minerals, and is therefore "soft." You can then compare the sudsing ability of a detergent in soft and hard water.
A large amount of suds will form in the bottle without epsom salts. Far fewer suds will form in the bottle containing the epsom salts.
The suds formed in this experiment are made of tiny bubbles. The bubbles are formed when air is trapped in a film of liquid. The air is trapped when it is shaken into the water. The film of liquid surrounding each bubble is a mixture of water and detergent. The molecules of detergent form a sort of framework that holds the water molecules in place in the film. If there were no detergent, the bubbles would collapse almost as soon as they are formed. You can see what this would look like by repeating the experiment, but leaving out the detergent.
This experiment will not produce suds if detergent for a dishwashing machine is used. (Try it and see.) No suds are formed because automatic dishwasher detergent is formulated so that it does not form suds. Suds create problems in a dishwasher. They interfere with the movements of the washing arms, and they are difficult to rinse off of the dishes.
The minerals that make water hard usually contain calcium and magnesium. In this experiment, you made water hard by adding epsom salt, which is magnesium sulfate. Calcium and magnesium in water interfere with the cleaning action of soap and detergent. They do this by combining with soap or detergent and forming a scum that does not dissolve in water. Because they react with soap and detergent, they remove the soap and detergent, thereby reducing the effectiveness of these cleaning agents. This could be overcome by adding more soap or detergent. However, the scum that is formed can adhere to what is being washed, making it appear dingy.
Water can be softened in a number of ways. An automatic water softener connected to water supply pipes removes magnesium and calcium from water and replaces them with sodium. Sodium does not react with soap or detergents. If you don't have an automatic water softener, you can still soften laundry water by adding softeners directly to the wash water. These softeners combine with calcium and magnesium, preventing the minerals from forming a soap scum.
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Lightning in Your Mouth (Density)

. Charge separation is produced as the candy fragments, and the discharge produces light. This phenomenon is called triboluminescence and can be observed with other flavors of hard candy--or even sugar cubes, but wintergreen flavor seems to work best.
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Rubber Bones (Chemical Reaction)

So what happened? What is so special about vinegar that it can make a hard bone squishy? Vinegar is considered a mild acid, but it is strong enough to dissolve away the calcium in the bone. Once the calcium is dissolved, there is nothing to keep the bone hard - all that is left is the soft bone tissue.
Now you know why your mom is always trying to get you to drink milk - the calcium in milk goes to our bones to make our bones stronger. With some effort and you can really get the bone to bend.

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Pushing Air (Thermal Coductivity)

The air inside the bottle heats up. It is gaining energy from the hot water. This energy causes the air molecules to move about more, which means they press outwards with more force. Since the pressure inside the bottle is higher, the balloon is pushed outwards, just like if you squeezed the bottle. The difference is , you are increasing the pressure by adding heat energy instead of by making the available space smaller.
When you put the bottle in the freezer the balloon is now inside out, inside the bottle. It may even be partially inflated inside the bottle. What has happened? As the air inside the bottle got colder, it contracted and pulled the balloon into the bottle, right?
No. Air can't pull things. It can push more or push less, but it can't pull. As the air inside the bottle gets cold, it loses heat energy. That causes the molecules in the air to move about less, so they push on the balloon with less force. Now the air pressure on the outside is greater, so the balloon is pushed inwards.
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Oil and Water and Static, Oh My! (Polarity)

Bring the balloon near the stream of water, and you should see that it bends towards the balloon. You may even see drops leap from the stream to the balloon.
The same thing with a thin stream of oil.This time it did not bend or react to the static charge.
That was because water is polar and oil is nonpolar. What in the world does that mean? No, it doesn't mean that you don't find oil at the North Pole. If a molecule is polar, then one part of the molecule will have a positive charge and another part will have a negative charge. Nonpolar molecules have a neutral charge all over. That should mean that the polar molecules will be pushed or pulled by the electrostatic charge on our balloon. To test that, youdid the experiment again, using some SYRUP Since it is water based, it is also a polar liquid. The charge of the balloon did the same thing to the syrup that it did for the water, showing me that even thick liquids are bent by the static charge.
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Static in a Balloon (Static Electricity)

Even before you touch the balloon, some of the pepper jumps away. When you touch the balloon, more of the pepper jumps away. As you move your finger along the surface of the balloon, the pepper will jump from place to place. Why is it doing that?
In some ways, static charges are like magnetic charges. With magnets, a North Pole and a south pole will stick together, while two north poles or two south poles will push away from each other. In other words, opposites attract and like charges repel. The same is true for positive and negative static charges.
When you rub the balloon against your hair, electrons (tiny, negatively charged pieces of atoms) move from your hair to the balloon. The balloon winds up with extra electrons, giving it a negative charge. Your hair winds up missing some electrons, leaving it with a positive charge.
The grains of pepper start balanced, with their positive and negative charges canceling each other out. The negative charge of the balloon pushes some of the electrons in the pepper to the far end of the grain. That gives the grain of pepper two charged ends. The end towards the balloon is positive, and the end away from the side of the balloon is negative. The positive end is attracted to the negatively charged rubber, causing the pepper to stick.
When you move your finger up to the balloon, you change things. As your finger gets near the balloon, your finger is charged; in the same way the pepper was. The tip of your finger takes on a positive charge. Since your finger is larger than the pepper, it pulls more of the negative charges in the rubber to the outside of the balloon. That leaves a positive charge on the inside of the rubber. The positive charge on the rubber and the positive charge on the pepper will now push away from each other. At the same time, the surrounding parts of the balloon are still negative,so they attract the pepper and it jumps to them. After you play with the balloon for a while, it will have a mix of positive and negative charged spots scattered on its surface. That can lead to all sorts of strange behavior, giving you all sorts of challenges to figure out what is going on.Just remember that like charges repel and opposite charges attract, and you should be able to reason out what is happening. C

Boat Puzzle (Sink and Float)

Those of you that actually tried the experiment know the answer. The water level dropped. Why? Think about why things float or sink.
In The boat floats because the combined weight of the boat and its contents weighs less that the amount of water which would take up the same space. If you put the boat into the water and then put the anchor in the boat, what happens? The boat sinks a little lower, due to the added weight of the anchor, right? How much lower? That depends on the weight of the anchor. If the anchor weighs as much as a gallon of water, then the boat will sink until it has pushed aside one gallon of water. This anchor weighs as much as 5 gallons of water, so the boat will sink until it has pushed aside 5 gallons of water.
What would happen to the water level in the pool when you put the anchor into the boat? It would rise, right. The boat is sinking lower, which means it is taking up more space in the pool. The water that it pushes aside has to go somewhere. The water level in the pool rises by 5 gallons, the amount of water you pushed out of the way by adding the anchor.
Now, lets take the anchor out of the boat and put it into the water. When you take the anchor out of the boat, the boat floats higher again. It is no longer pushing aside those 5 gallons of water, so the water level in the pool drops by 5 gallons back to where it was at the start.
But, then we put the anchor into the pool. Our anchor is heavier than water. It weighs as much as 5 gallons of water, but it only takes up as much space as one gallon of water. When it sinks to the bottom, it pushes aside only one gallon of water.
So when we move the anchor from the boat to the pool, two things change the water level. Removing the anchor from the boat causes the water level to drop by 5 gallons. Adding the anchor to the water causes the water level to rise by one gallon. That means that the total impact is that the water level in the pool would drop by 4 gallons.
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