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What happens if you chew gum and chocolate at the same time? You'll find out in this sweet candy science experiment while learning an important concept in chemistry: solubility. Click and expand the tabs below to get started What you'll need
experimental procedure
what's happening
This is a chemistry experiment, even though you are doing it in your mouth! It illustrates a very important concept in chemistry called solubility, which is the ability of one substance to dissolve another substance. Chemists say that “like dissolves like” and this is an example of that. If your gum was candy coated, like a Chiclet or gum-ball, you should have noticed that the candy coating dissolved or disappeared as soon as you began chewing. This is because the candy coating was made of sugar, which easily dissolves in water (try adding a spoon full of table sugar to a glass of water and watch what happens), and the saliva in your mouth is mostly water. Chemists would say that sugar is soluble in water. Saliva and chewing are the first steps in digesting or breaking down your food into simpler components that your body can use for energy. Your saliva does not dissolve the gum, however, because most modern chewing gums are made of a synthetic rubber (i.e. man-made, not natural), which is a type of oil-based polymer, such as butadiene-styrene, vinyl acetate, or polyethylene (the same material in plastic grocery bags). You may have already learned that oil (as well as oil-based substances) and water don't mix- they are not alike. But chocolate does contain oil-based fatty substances, so the chocolate dissolves the gum. Like dissolves like. After adding the first piece of chocolate and chewing you should have noticed that the gum was much softer and stickier, and maybe much smaller than it was after you first chewed the gum alone. If you add enough chocolate to the gum in your mouth (you may need 3 or 4 pieces) and continue chewing you should be able to make the gum disappear completely! variations and related activities
If you're not allergic to peanuts, try chewing a spoon full of peanut butter with your gum instead of chocolate. Does the peanut butter also make the gum disappear? Why do you think that is? Instead of doing the entire experiment in your mouth, just chew the gum for a minute or two in your mouth, then put it in a cup or small bowl instead. Add a couple spoonfuls of vegetable oil to the cup and use a spoon to stir and grind the gum. Does it dissolve? If not, add a little more vegetable oil. Try repeating ths experiment with some other liquids. Is gum more or less soluble in other liquids? Solubility has it's limits, however, and you can easily test this. Add one or two spoonfuls of sugar to a glass of water and observe what happens. Does all of the sugar dissolve immediately? Observe for a minute or two, has more dissolved? Use a spoon tp stir the water and sugar. Does it dissolve more easily? Try adding more spoonfuls of sugar and stirring. Does the sugar continue to dissolve? Keep adding sugar until it will no longer dissolve in the water. Now you have reached the solubility limit- the water simply can't hold any more sugar and we say it is saturated. What would happen if you added more water to the glass? Solubility also depends temperature. With the help of an adult try repeating this experiment with warm or hot water. Is sugar more soluble in hot water, i.e. can you make more spoonfuls of sugar dissolve? Coming soon: make rock candy float letters off M&M's pop rocks dancing raisins carbonated soft drinks Lava Lamps Dissolve egg shell in vinegar Underwater fireworks (food coloring dissolves in water but not oil) Oil-based and water-based paints references and links to more information
Journal of Chemistry Education Classroom Activity #105. A Sticky Situation: Chewing Gum and Solubility Learn more about solubility: Coming soon: Saliva Digestion Solubility experiments
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What you'll need
experimental procedure
what's happening
You may have heard someone say that water and oil don't mix. The molecules (the arrangement of atoms that make up these chemicals) that make up water are very different from molecules that make chemicals like vegetable oil. Water molecules (or H2O) attract other water molecules and oil molecules can (weakly) attract other oil molecules, but water molecules strongly repel oil molecules, kind of like the way magnets repel each other if you point the north pole of one towards the south pole of the other. Thus when you add oil to water they will separate into different layers, and the oil layer will float to the surface because oil is less dense than water. This is the scientific term which means that a cup of water has more mass (and is therefore heavier) than the same cup filled with oil. The force that causes the oil to float above the water layer is called the buoyant force or just buoyancy. Since the food coloring is dissolved in water, these drops also will not mix with oil and sink to the bottom of your cup where they burst and mix with the water to color it. The solid Alka-Seltzer pieces are more dense than the oil or the water, so they sink all the way to the bottom. As soon as they reach the water they begin to dissolve and a chemical reaction takes place between two of the ingredients that produces carbon dioxide gas bubbles. As these bubbles rise they pull some of the water along with them and have enough buoyancy to rise through the oil layer, but once they reach the surface the bubbles pop and the gas escapes. Now the water droplets are too heavy to float, and they fall back through the oil where they may pick up another gas bubble to rise again. This process resembles the rising and falling bubbles in a Lava Lamp, but it works a little differently. A real Lava Lamp also contains two immiscible liquids (i.e. they don't mix) with different densities, but it uses the energy from a light bulb underneath to warm the lower liquid. As it warms it expands and its density decreases, allowing bubbles to rise up through the upper liquid. As these bubbles float higher (and farther away from the heat source) they cool down, become denser once again, and fall back into the lower layer where the process can repeat. The upper liquid also warms during this process, but it was carefully chosen so that its density does not decrease as much, so that it still provides enough buoyant force to push the bubbles from the lower liquid upwards. See the reference link below for a more detailed explanation. variations and related activities
references and links to more information
Alternative Lava Lamp experiments:
How real Lava Lamps work: More about the differences between and oil and water molecules:
Try some cool density column experiments:
More about density and buoyancy:
More cool buoyancy experiments:
Click and expand the tabs below to get started. What you'll need
experimental procedure
What's happening
You may have heard someone say that water and oil don't mix. The molecules (the arrangement of atoms that make up these chemicals) that make up water are very different from molecules that make chemicals like vegetable oil. Water molecules (or H2O) attract other water molecules and oil molecules can (weakly) attract other oil molecules, but water molecules strongly repel oil molecules, kind of like the way magnets repel each other if you point the north pole of one towards the south pole of the other. Thus when you add oil to water they will separate into different layers, and the oil layer will float to the surface because oil is less dense than water. This is the scientific term which means that a cup of water has more mass (and is therefore heavier) than the same cup filled with oil. The force that causes the oil to float above the water layer is called the buoyant force or just buoyancy. Since the food coloring is dissolved in water, it also will not mix with oil and sinks to the bottom of your cup. When you gently pour the oil and color droplets from your cup onto the surface of the large container they first mix with the rest of the oil floating on the surface and the color droplets start to sink. As they reach the bottom of the oil layer they cling there for a few seconds until they can finally break through into the water below. Once they make it into the water the food color droplets can begin to dissolve, and because they are just slightly more dense that the rest of the water (the food coloring chemicals give it a little more mass) they slowly sink and create the beautiful color streaks that look sort of like fireworks exploding in slow motion! variations and related activities
What difference does it make if you use hot water instead of cold water? For a bigger "explosion", try carefully adding a drop of food color directly to the oil puddle on the surface, but don't get too much color in the water or you won't be able to see what's happening. You can learn more about density and buoyancy by making a density column, where several different (usually colorful) liquids are carefully poured into a tall container where they separate into many layers. Check out the links below to try this experiment for yourself. There are several other fun activities and experiments which demonstrate buoyancy, like the Cartesian Diver bottle and Dancing Raisins. See the links below to have some fun. references and links to more information
More about the differences between and oil and water molecules:
Try some cool density column experiments:
More about buoyancy:
Try some cool buoyancy experiments:
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