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Faraday At Home

The following content is provided by University of Utah student Anastasia Borodai as an Honor's Thesis in collaboration with Professor Thomas Richmond.

ABSTRACT

Michael Faraday is a well-known name in the field of science, known for his discoveries in electromagnetic induction, electro-magnetic rotations, the magneto-optical effect, diamagnetism and field theory, (6) he remains a name discussed in many Chemistry and Physics lectures to this day. However, one of his lesser known prized accomplishments is a series of lectures given to audiences of all ages, which to this day remains relevant.

read the full abstract

Experiments

 Ice Cream Title

Materials:

  • 1 cup half & half or milk
  • ½ teaspoon vanilla v
  • 2 tablespoons sugar
  • 4 cups crushed ice
  • ½ cup rock salt
  • 2 quart size zip-top plastic bags
  • 1 gallon size zip-top freezer bag
  • crushed cookies, candies, nuts, sprinkles or berries (optional for add-ins)

Before you begin here are some questions to get you thinking about this experiment:

  1. What is the freezing point of water?
  2. What is the freezing point of salt water?
  3. Is the freezing point of salt water warmer or colder than plain water?
  4. What happens when you put salt on ice, like on an icy road in winter?
  5. So why do we mix salt with ice to freeze ice cream?

Answers to the above questions:

  1. 32 degrees Fahrenheit or 0 degrees Celsius
  2. The freezing point of salt water actually depends on how much salt is in the water.
  3. The freezing point of salt water is colder than plain water, when salt dissolves into the liquid water therefore lowering the freezing point, this is freezing point depression. Ice forms when the­ temperature of water reaches 32 degrees Fahrenheit (0 degrees Celsius). Salt lowers the freezing/melting point of water, so in both cases the idea is to take advantage of the lower melting point of salt
  4. Salt dissolves into the ice, lowering its freezing point causing it to unfreeze. This is because it now has to be colder than 32 degrees Fahrenheit (0 degrees Celsius) for ice to form. Salt doesn’t make the ice melt in your driveway or on the roads here in Utah, it actually acts to change the properties of water to be more similar to salt.
  5. When you are making ice cream, the temperature around the ice cream mixture needs to be lower than 32 F if you want the mixture to freeze. Salt mixed with ice creates a brine that has a temperature lower than 32 F. When you add salt to the ice water, you lower the melting temperature of the ice down to 0 F or so. The brine is so cold that it easily freezes the ice cream mixture.

Instructions:

  1. Pour the first three ingredients into a quart-size zip-top bag. Squeeze out air and seal the bag tightly. Place inside the second quart-size bag, and seal.
  2. Place the double-bagged ingredients inside the gallon-size freezer bag. Fill the freezer bag with ice, pour in the rock salt, squeeze out air, and seal.
    The salt will begin to melt the ice because salt lowers the freezing point of water.
  1. Now comes the fun part: Gently shake the bag, making sure the ice is evenly spread out. Continue to gently shake and knead the bag in your hands.
    The energy from shaking and kneading—and the heat transferred from your hands—causes the ice to melt further. Melting ice doesn’t look as cold as frozen ice, right? But remember, it’s mixed with salt. As the melting ice combines with the salt, the salt-water solution has a lower freezing point than plain water. So the melted ice is actually colder than the original ice!
  1. Can you guess how long it will take for the liquid to freeze into a solid? (It should take between 5—10 minutes.)
    During the ice-cream making process, the ice (a solid) turns into a liquid (melted ice). When ice absorbs energy, it changes the phase of water from a solid to a liquid. The ice absorbs energy from the ice-cream ingredients and also from your hands as you hold the bag. The molecules start moving around again as the ice melts.
  1. Use a thermometer to find the temperature of the melted ice. Was your guess on the mark?
  2. Eat your ice cream straight out of the bag, this is a great time to toss in any add-ins such as nuts, fruit, or sprinkles, then wash and recycle the bag to use it again!

Change it up!

Not all types of salt work the same. The larger the salt crystals, the more time it takes to dissolve. This keeps it colder, longer. You could experiment with table salt, kosher salt and rock salt to test this.

Questions to think about: Which salt has the larger crystals? Which salt will take longer to dissolve? Which salt will keep things colder longer?

Do some experiments and test solutions with different concentrations of salt to see how freezing points compare. You can have one person double the salt amount that is originally stated and compare who gets to their ice-cream mixture faster.

Questions to think about: Will more salt make the solution (salt+water) colder or warmer? How long will the ice-cream take to make now if you double the amount of salt? Triple it?

 

Invisible Ink

Materials:

  • One half of a lemon (use caution when cutting)
  • One half teaspoon of water
  • Small bowl
  • Spoon
  • White paper
  • Q-tips
  • A lamp with a lightbulb that puts off a lot of heat, such as a 100-watt incandescent bulb or another heat source, such as a radiator
    Optional: Pencil (to write a decoy message on your paper)

Before you begin here are some questions to get you thinking about this experiment:

  1. What is invisible ink?
  2. What is an acid?
  3. What fruits contain acids? (Think of fruits that taste sour)
  4. What makes invisible ink visible when using something like lemon juice?

Answers to the above questions:

  1. Invisible ink is any substance that you can use to write a message that is invisible until the ink is revealed.
  2. An acid is something that contains a lot of hydrogen (H+). If you were to take litinus paper (pH paper) it can help you see what around the house is an acid or base. Water is considered neutral and therefore neither an acid nor a base. Vinegar is considered an acid. Whereas drain fluid is a base (Bases contain a lot of hydroxides- OH-).
  3. Acids are considered to be a “sour” taste. Fruits such as lemons, limes, oranges, lots of the citrusy fruits tend to have acidic juices.
  4. Lemon juice—and the juice of most fruits, for that matter—contains carbon compounds. These compounds are pretty much colorless at room temperature. But heat can break down these compounds, releasing the carbon. If the carbon comes in contact with the air, a process called oxidation occurs, and the substance turns light or dark brown. Oxidation doesn't always need heat to occur. Some fruits themselves can turn brown from oxidation. Think of an apple or pear slice that is left out on the counter for too long.

Instructions:

  1. Squeeze the juice of your lemon half into the bowl. Add the water and mix with a spoon.
    Think of a secret message you would like to write—and to whom you're going to deliver it!
    Extra: If you want to be super-secret, you can write a boring old message or draw a picture on the paper with a pencil before you write your secret message to disguise it even further.
  1. Soak the Q-tip in the lemon juice-and-water solution. Use the damp Q-tip to write your top-secret message on the piece of paper.
  2. Wait a few minutes for the paper to dry. While you're waiting, you can switch on your lamp to give the lightbulb time to heat up (being careful not to touch the hot bulb itself).
  3. When the paper is dry, hold it up to the hot lamp for a few minutes (but don't let the paper get so hot that it burns). What happened? How long did it take for your message to show up?

Change it up!

There’s a lot of acids that you can find in your kitchen and not all of them will be exactly the same. What other acidic things can you find in your house to use? Some examples: apple juice, vinegar, orange juice, etc.

Questions to think about: Which acids work better? Some acids are better than others, why?

 

Crystal Geodes

Materials:

  • Approximately 2 lbs. of Alum Powder (Potassium Aluminum Sulfate)
  • 12 Eggshells (6 eggs split in half)
  • Elmer’s Glue (need plenty)
  • Paintbrush
  • A box, paper plate, or paper towel to set your eggs in/on during the drying process
  • A large bowl
  • A spoon/whisk
  • A measuring cup
  • Food coloring (optional)

Before you begin here are some questions to get you thinking about this experiment:

  1. What is a geode?
  2. How do geodes form?
  3. How can I make a geode from an egg?

Answers to the above questions:

  1. A geode is a particular type of rock formation which can occur in sedimentary as well as some volcanic rocks. These geological rock formations are most commonly limestone on the outside, while the inside is hollow and full of quartz crystals.
  2. A geode starts off as a bubble or an empty space left behind by animals, tree roots, and dozens of other things. Water is trapped in this bubble, which contains silica precipitation (Silicon is right under Carbon on the periodic table) that can also have various minerals and elements. The basic crystals of a geode are made of quartz (silicon dioxide) and are colored based on the contents of the surrounding soil. Over thousands of years different layers of silica precipitation cool and create different layers of crystals.
  3. Your eggshell geode is formed through a process called sedimentation. While a geological geode is a mass of minerals within a rock that can take thousands, even millions, of years to form, your Incredible Egg Geode only takes a couple of days. The heated alum solution contains suspended particles of alum powder in it and as the solution cools, these particles of alum begin falling to the bottom. When the alum particles settle on the bottom, they begin crystallizing. Coating the shell with alum powder beforehand gives the suspended alum particles a surface to which they can more readily attach themselves. The particles that settle onto the interior surface of the shell crystallize quickly but you will also see evidence of crystallization on other parts of the shell as well as on the bottom and sides of the bowl.

Instructions:

  1. You have an egg, now you need to get all the yolk and egg white out of it but you need the shell to be split in half. This can be done many ways. Simply breaking the egg like when making breakfast is the easiest.
  2. Carefully wash the inside of the shell halves with warm water and wipe them dry with a paper towel. Get the interior surface of the egg as clean and dry as possible without cracking it. Peel off and throw away small pieces of shell from around its edge.
  3. Once the egg is dry it is time to apply the Elmer’s glue to the shell. Generously drip some glue into the shell halves. A little on the outside is OK, too.
  4. Use the paintbrush to spread the glue all over the inside of the shell. Completely cover the interior surface with glue all the way up to, and including, the edges. Use more glue if needed.
  5. While the glue is still wet, generously sprinkle lots of alum powder on the wet glue.
  6. Turn the shell-half over and gently tap out any excess alum. Place your egg(s) on a paper towel, paper plate, or in a box to dry overnight.
  7. The next day, bring two cups of water (473 ml) almost to a boil and pour it into a bowl.

    NOTE: If you plan to make more than one color of geode, use one cup (237 ml) of water and adjust the food coloring and alum amounts accordingly
  1. Dissolve 30-40 drops of food coloring into the water. Use any color or color combination you wish. Stir it well. (optional- this produces colored crystals)
  2. Dissolve ¾-cup alum powder into the water.
  3. Stir it well and make sure it dissolves completely. Let the mixture cool for 30 minutes.
  4. When it’s cool, place the shells into the solution alum-side up. Gently push the shells to the bottom of the solution with the spoon and allow them to sit there for 12-15 hours.
  5. After 12-15 hours, alum crystals have grown! Carefully remove the shells and place them on a paper towel to dry and finish the geode-creation process. Perhaps you can leave them in the bowl longer and see if they grow bigger.

Change it up!

Alum crystals are awesome to grow because many different factors affect their crystal growth.

One of the things that can effect crystal growth is the cooling rate. In other words you can change the size of the crystals size based on how fast they can cool. Let the solution cool normally, cool it faster with a few pieces of ice, cool it really fast with a lot of ice (be careful if you’re using a glass bowl – freezing a glass bowl full of hot liquid is a recipe for a broken bowl and giant mess), cool it super slow by keeping the solution in a pan on the stove at a very low temperature. One of the above will result in a few huge crystals and one in scads of tiny crystals.

Questions to think about: Which of the cooling rates will make the biggest crystals? The smallest?

 

Elephant Toothpaste
Materials:

  • An empty 20 oz soda bottle (or any tall skinny clear container)
  • Hydrogen peroxide (you can get 3% at the grocery store, or 8% at a beauty supply store)
  • Active yeast
  • Warm water
  • Liquid dish soap
  • Food coloring - optional - but it does make a nice color!

Before you begin here are some questions to get you thinking about this experiment:

  1. What does it mean when something is decomposing?
  2. What types of things decompose? (Think about after you eat fruit, does the skin decompose?)
  3. What is hydrogen peroxide used for? (You probably have it in your medicine cabinet!)
  4. What is hydrogen peroxide?
  5. What is a catalyst?

Answers to the above questions:

  1. When something is decomposing it means it’s being broken down into its parts. For example, if you leave an apple on the table for several days it starts to “go bad,” that’s the apple decomposing.
  2. Apples, Oranges, Grass, Eggs, just about everything can decompose!
  3. You may have gotten a cut on your hand or leg before and your parents may have used hydrogen peroxide on the cut. Did you notice it fizzing/bubbling? Hydrogen peroxide acts a disinfectant meaning that it helps to clean your cut getting rid of all the bad bacteria that shouldn’t be there. The fizzing/bubbling means that hydrogen peroxide is decomposing!
  4. The chemical formula for hydrogen peroxide is H2O2.  It looks pretty similar to the chemical formula for water, which is H20, except that hydrogen peroxide has an extra "O", an extra oxygen.  Hydrogen peroxide is not a very stable compound, so, it is always decomposing to water and oxygen, but under normal conditions, the decomposition goes very slowly.  In this reaction, yeast catalyzes the decomposition, making the reaction go much more quickly.  If you add a little dishwashing detergent, you get foam!  If you add food coloring, you get colored foam!
  5. A catalyst is something that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. This means that your catalyst isn’t part of the reaction, but helps the rate of the reaction.

Instructions:

*Make sure you’re doing this experiment in an area you can easily clean up, it can get very messy very quickly

  1. Mix 1/2 cup of hydrogen peroxide with ¼ cup of liquid dish soap and a few drops of food coloring.  
  2. Add this mixture to the soda bottle and place it in the sink or on a cookie sheet.
  3. In a separate container, mix one packet of active yeast with warm water and let sit for 5 minutes.
  4. When you are ready, pour the yeast mixture into the soda bottle (a funnel might be helpful) and watch the reaction! How much foam was made?

Change it up!

Yeast was our catalyst in this experiment. Does it matter if you use lukewarm water to activate the yeast or cold water?

Questions to think about: Which catalyzes the reaction more, yeast that was activated with warm or cold water? Does temperature matter?

When hydrogen peroxide decomposes it makes oxygen gas (the stuff we need to breathe!) it is made more noticeable by adding some dish soap, which makes the foam.

Questions to think about: What happens if you add more or less soap? What happens if you don't add any soap?


Saturation Part I

Materials:

  • Clear glasses (3)
  • Tap water
  • Salt
  • Spoon
  • A saucepan or a microwave in order to heat water
  • Ice or a refrigerator to cool water

Before you begin here are some questions to get you thinking about this experiment:

  1. What happens when you add hot chocolate to milk/water?
  2. What does it mean when something dissolves?
  3. What is saturation?
  4. Can you list some things that don’t dissolve in water?
  5. Can you list some things that do dissolve in water?

Answers to the above questions:

  1. If you say it disappears you’re on your way to being right. What happens is it dissolves.
  2. Dissolving is when the solute breaks up from a larger crystal of molecules into much smaller groups or individual molecules. This break up is caused by coming into contact with the solvent.
    For example, with salt water, the water molecules break off salt molecules from the larger crystal. Each salt molecule still exists.
    It is just now surrounded by water molecules instead of fixed to a crystal of salt. 
  1. When a solution reaches the point where it cannot dissolve any more solute it is considered "saturated."
  2. Cooking oil, toy cars, keys, stuffed animals
  3. Sugar, salt, herbs, medicine

Instructions:

  1. Cool 2 cups of water in the fridge/freezer, or with ice.
  2. Heat 2 cups of water in a saucepan over the stove or in the microwave.
  3. Fill one clear glass with 1 cup of room temperature water.
  4. Fill another clear glass with 1 cup of ice water or cold refrigerated water that you prepared earlier.
  5. Fill another clear glass with 1 cup of hot water from saucepan or microwave. (Be careful.)
  6. Take a guess which one will dissolve the salt the fastest? Which one will become saturated first?
  7. Put one spoonful of salt in each glass and stir after each spoonful.
  8. Continue to put individual spoonfuls of salt until the salt stops dissolving. When the salt stops dissolving this means you have reached your saturation limit. The water can’t dissolve anymore salt!

Change it up!

What you’re watching when the salt dissolves is actually a reaction rate and these can be affected by many things, in this experiment we compared cold water to room temperature water to hot water.

Questions to think about: What temperature of water increases the reaction rate (dissolves faster)?

Stirring the salt after adding it also affects the reaction rate by allowing each individual salt crystal to interact with water, this stirring is a form of agitation.

Questions to think about: What would happen if you didn’t stir in the salt?

Super-saturation is when a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances. You can see this happen! Go back to your experiment with the glass of hot water, you now know the saturation limit, grab a new glass and fill it with hot water put in the amount of salt you needed to get to the saturation limit (the salt must still dissolve). Then let the glass cool. Once it’s cooled down, add a spoonful of salt and watch!


Saturation Part II

Materials:

Before you begin here are some questions to get you thinking about this experiment:

  1. What is saturation?
  2. What makes the crystals grow in order to make our candy?
  3. What does heating the water allow to happen? (Think back to part 1 of this experiment)

Answers to the above questions:

  1. When a solution reaches the point where it cannot dissolve any more solute it is considered "saturated."In this case when you start adding sugar and it doesn’t dissolve anymore.
  2. Two different methods will contribute to the growth of the crystals on the string. You have created a supersaturated solution by first heating a saturated sugar solution (a solution in which no more sugar can dissolve at a particular temperature) and then allowing it to cool. A supersaturated solution is unstable—it contains more solute (in this case, sugar) than can stay in a liquid form—so the sugar will come out of solution, forming what's called a precipitate. This method is called precipitation.

    The other is evaporation—as time passes, the water will evaporate slowly from the solution. As the water evaporates, the solution becomes more saturated and sugar molecules will continue to come out of the solution and collect on the seed crystals on the string. The rock candy crystals grow molecule by molecule. Your finished rock candy will be made up of about a quadrillion (1,000,000,000,000,000) molecules attached to the string.
  1. To make rock candy, we initially used more sugar than could dissolve in water at room temperature (three cups of sugar for one cup of water). The only way to get all of that sugar to dissolve is to heat up the water, because increasing the temperature causes more sugar to dissolve in water. If we increase the temperature, we increase the dissolving process, and if we reduce the temperature, we decrease the dissolving process.

Instructions:

  1. Combine equal parts of sugar and water in a saucepan and heat until all of the sugar is dissolved
  2. Then slowly add more sugar in small amounts until it will no longer dissolve in the water  
  3. The water should start to look a little cloudy.  That is the point when no more sugar is dissolving and the perfect sugar saturation has been reached.  Basically, you are creating a saturatedsugar solution (a solution in which no more sugar can dissolve at a particular temperature) the amount of sugar verses water used should be roughly 3:1.
  4. Continue to heat the water until it comes to a simmer. 
  5. Remove the sugar-water from the heat and allow it to cool.  While it is cooling you can prepare your skewers or candy sticks.  Cut theskewers to a desirable size for the jars you are using.  Then dip the sticks in water and roll them in sugar
  6. Allow the sugar coated sticks to dry.  While those are drying you can prep your jar(s).  Once your sugar-water is cool enough pour it into jars and add food coloring if desired.  Then, once the sticks are dry place them in the jar(s).  
  7. Make sure that the sugar coated sticks are completely dry before placing them in the jars.  The rock candy needs the sugar to grow on, and if the sugar on the sticks isn't dry it will dissolve in the water.  It is also important to make sure that the sticks are not touching the bottom or sides of the jar

Change it up!

What you’re watching when the sugar dissolves is actually a reaction rate and these can be affected by many things, in this experiment we used hot water to saturate our water with sugar.

Questions to think about: What would happen if we used colder water? What about room temperature water? Do you think this would affect your crystals?

 

Microplastics

Materials:

  • Facewash/face scrub containing polyethylene in its ingredients
  • Hot water (heated from a pan or in the microwave)
  • Clear Glass Cup
  • A spoon
  • A coffee filter

Before you begin here are some questions to get you thinking about this experiment:

  1. What does micro mean?
  2. Where do we find microplastics?
  3. Do you think microplastics dissolve in water?
  4. What happens if microplastics don’t dissolve in water?
  5. Why do you think microplastics are important to environmental chemistry?

Answers to the above questions:

  1. If you guessed that micro means small, you are correct. Micro refers to something extremely small. Sometimes it’s something so small that you can’t see it with the naked eye.
  2. Microplastics are found in cosmetics, clothing, and industrial processes. So we either make microplastics directly of microplastics come from the breaking down of large plastics into micro sized ones.
  3. Most plastics don’t break down for many years. If you leave a plastic toy outside in your yard for several years, it won’t break down. This means that they won’t dissolve in water. If you drop a plastic toy in water, it doesn’t dissolve.
  4. This means microplastics stay in water. We may not be able to see them, but they are there.
  5. The first International Research Workshop on the Occurrence, Effects and Fate of Microplastic Marine Debris says Microplastics are a huge concern for our marine environment because of the following:
  • The documented occurrence of microplastics in the marine environment,
  • The long residence times of these particles (and, therefore, their likely buildup in the future), and
  • Their demonstrated ingestion bymarine organisms.

This means that when microplastics get into the environment they are hard to get out and can cause problems. Their inability to dissolve and remain in the environment for extended periods is a concern for the Environmental Chemistry field.

Instructions:

  1. Heat water, it does not need to be boiling, but the warmer the better.
  2. Pour the water into the clear glass cup, be careful when touching the glass it will be very hot.
  3. Squeeze your facewash/face scrub into the glass with hot water. The more you squeeze in the more microplastics you will observe. As a suggestion you can always squeeze in more at a later time.
  4. With your spoon stir the facewash/face scrub and water mixture very slowly. This will dissolve the facewash/face scrub, but as mentioned earlier the microplastics will remain.
    DO NOT stir quickly. This will cause bubbles and you don’t want bubbles forming or else it will be difficult to see the microplastics.
  1. Once the facewash/face scrub is dissolved at this stage you may add more to get more microplastics or continue on.
  2. By now you should be able to see a light film on top of the water. This film if you slowly move it around is actually a film of microplastics. If you move it around with your spoon you can decipher that these are small plastic beads.
  3. Filter the water/facewash/microplastic solution through the coffee filter. This will drain out the water and facewash leaving behind the microplastics on the filter paper.

 Change it up!

Water is used in this experiment to dissolve the other products in facewashes and face scrubs whereas it cannot dissolve microplastics this means what is left behind that we can see is microplastics.

Questions to think about: What would happen if we used colder water? What about room temperature water? Would different temperatures of water affect the dissolving of the facewash products more or less?

Read about it:

If you’re interested more about how this affects our environment, read about the Great Pacific Garbage Patch and what you can do at home to help the environment.

 

Colored Flames

Materials:

  • Menthol/methanol or isopropyl alcohol (rubbing alcohol) (an alcohol that will burn is needed)
  • Epsom salt (Magnesium Sulfate)
  • No salt - salt substitute (potassium chloride/bitartrate)
  • Borax (Boric acid) (Boron)
  • Table Salt (Sodium Chloride)
  • 4 Bowls (Metal or Glass. DO NOT use Plastic) (the bowl can also be reused requiring just 1 bowl)
  • Lighter torch (long stem or bbq)

Before you begin here are some questions to get you thinking about this experiment:

  1. What color is fire?
  2. Do you think that different colors in fire are hotter than others?
  3. All of the chemicals we are using have metals. What is a metal, think about metals you see around you, what make them a metal?
  4. Do different metals give off different colors?
  5. What do you think makes fireworks different colors? (Consider the other questions asked)

Answers to the above questions:

  1. Fire usually tends to be white, yellow, orange, and red.
  2. Near the logs or at the very heart of the fire, where most burning is occurring, the fire iswhite, the hottest color possible for organic material in general, or yellow. Above the yellow region, the color changes to orange, which is cooler, then red, which is cooler still. In a standard fire, white would be the hottest.
  3. Metals are everywhere, sometimes you may not even know something is a metal, but it is. The salt you eat is made out of Sodium and Chloride. Sodium is the metal, look up a picture of Sodium and see what it looks like. Metals tend to be solid, shiny, good conductors of heat and electricity, ductile (can be made into thin wires), and malleable (can be hammered into thin sheets.)
  4. Yes! That’s the point of our experiment today. Each metal gives off a unique color. In fact, the color of the flame could help you identify what the metal is if you didn’t know what it was before.
  5. Different metals being burned give off the different colors we see in fireworks.

Instructions:

WHITE FLAME

  1. Pour 1/4 cup of magnesium sulfate into the bowl.
  2. Pour 1/2 cup of the alcohol into the bowl.
  3. Light the mixture with the lighter torch.
  4. Observe

YELLOW FLAME

  1. Pour 1/4 cup of sodium chloride into the bowl.
  2. Pour 1/2 cup of the alcohol into the bowl.
  3. Light the mixture with the lighter torch.
  4. Observe

BLUE VIOLET FLAME

  1. Pour 1/4 cup of potassium chloride/bitartrate into the bowl.
  2. Pour 1/2 cup of alcohol into the bowl.
  3. Light the mixture with the lighter torch.
  4. Observe

GREEN FLAME

  1. Pour 1/4 cup of boric acid into the bowl.
  2. Pour 1/2 cup of alcohol into the bowl.
  3. Light the mixture with the lighter torch.
  4. Observe

 

Strawberry DNA

Materials:

  • Strawberry
  • Isopropyl alcohol (5 mL) (also known as rubbing alcohol)
  • Dish soap (10 mL)
  • Salt (1/4 tsp)
  • Zipper-lock bag
  • Strainer
  • Water (90 mL)
  • Measuring cups and spoons
  • Small glass container
  • Tweezers
  • Pipette (optional)
  • Spoon

Before you begin here are some questions to get you thinking about this experiment:

  1. What is DNA?
  2. What has DNA? Do we have DNA?
  3. Why do we use strawberries?
  4. What is extraction?

Answers to the above questions:

  1. DNA stands fordeoxyribonucleic acid. It’s the genetic code that determines all the characteristics of a living thing.  Basically, your DNA is what makes you, you. Or even, what makes a strawberry a strawberry.
  2. DNA is present in every cell of all plants and animals and determines all genetic traits of the individual organism. If something is considered alive and living, it has DNA. We have DNA and our DNA makes us who we are. Rocks on the other hand and other non-living things don’t have DNA.
  3. While other fruits are soft and just as easy to pulverize, strawberries are the perfect choice for a DNA extraction lab for two very good reasons: (1) they yield way more DNA than other fruits, and (2) they are octoploid, meaning that they have eight copies of each type of DNA chromosome. (Human cells are generally diploid, meaning two sets of chromosomes.) These special circumstances make strawberry DNA both easy to extract and to see.
  4. Extraction is the process of removing something from something else. In this case we are removing DNA from strawberries. To extract the DNA, each component of the extraction mixture plays a part. Soap helps to dissolve cell membranes. Salt is added to release the DNA strands by breaking up protein chains that hold nucleic acids together. Finally, DNA is not soluble in isopropyl alcohol, especially when the alcohol is ice cold.

Instructions:

  1. Put a bottle of isopropyl alcohol in a freezer. We’ll come back to it later. Measure 6T (90 ml) of water into a small glass container.
  2. Add 2 tsp (10 ml) dish soap to the water.
  3. Stir in a ¼-tsp salt and mix until the salt dissolves. This is the extraction mixture.
  4. Place one strawberry into a plastic zipper-lock bag.
  5. Pour the extraction mixture into the bag with the strawberry.
  6. Remove as much air from the bag as possible and seal it closed.
  7. Use your hands and fingers to mash, smash, and moosh the strawberry inside of the bag. You don’t want any large pieces remaining.
  8. Pour the resulting strawberry pulp and extraction mixture through a strainer and into a medium glass bowl or similar container.
  9. Use a spoon to press the mashed bits of strawberry against the strainer forcing even more of the mixture into the container. From the container it’s in now, pour the extraction mixture into a smaller glass container that holds ¼- to ½-cup (50-100 ml) of fluid. This will help to isolate the DNA on the surface of the mixture.
  10. Add 1 tsp (5 ml) of the chilled isopropyl alcohol to the solution and hold the mixture at eye level. You’re looking for a separation of material that shows up as a white layer on top. That’s the DNA of the strawberry!
  11. Use the tweezers to gently remove the DNA from the solution and lay it on a dish to examine.

Change it up!

DNA can be found in all living things, but sometimes extraction may be difficult. Consider other fruits to extract with. Bananas and kiwis are two other fruit that you can extract DNA from. Extraction here is the key element. If you can’t extract, you can’t get the DNA.

Questions to think about: What would happen if we you missed a step in the extraction? What would happen if you added more of one extraction step then another? (Added more salt than what was needed)

 

Exploding Lunch Bag

Materials:

  • One small (sandwich size) zip-lock bag – freezer bags work best.
  • Baking soda
  • Warm water
  • Vinegar
  • Measuring cup
  • A tissue

Before you begin here are some questions to get you thinking about this experiment:

  1. What is an acid? What’s the acid in our experiment?
  2. What is a base? What’s the base in our experiment?
  3. What’s being made in the reaction to make the bag pop? (It’ll look like the bag is starting to puff up, can you think of a type of gas that may be made from this reaction? You breathe out this gas.)
  4. What is the tissue for?

Answers to the above questions:

  1. An acid is something that contains a lot of hydrogen (H+). If you were to take litinus paper (pH paper) it can help you see what around the house is an acid or base. Water is considered neutral and therefore neither an acid nor a base. Vinegar is considered our acid in this experiment.
  2. A base is something that contains a lot of hydroxide ions (OH-). If you were to take litinus paper (pH paper) it can help you see what around the house is an acid or base. Water is considered neutral and therefore neither an acid nor a base. Baking Soda (sodium bicarbonate) is our base in this experiment.
  3. Any reaction between and acid and base results in Carbon Dioxide (CO2) and water. The Carbon Dioxide is the gas that is being built up the experiment and in fact, it can be found in many places, you breathe out Carbon Dioxide every day. In this experiment the bag cannot have any more pressure from all of the gas made and it pops.
  4. The tissue buys you some time to zip the bag shut. Basically the tissue gets in the way of the reaction.

Instructions:

  1. Go outside – or at least do this in the kitchen sink.
  2. Put 1/4 cup of pretty warm water into the bag.
  3. Add 1/2 cup of vinegar to the water in the bag.
  4. Put 3 teaspoons of baking soda into the middle of the tissue
  5. Wrap the the baking soda up in the tissue by folding the tissue around it.
  6. You will have to work fast now – partially zip the bag closed but leave enough space to add the baking soda packet. Put the tissue with the baking soda into the bag and quickly zip the bag completely closed.
  7. Put the bag in the sink or down on the ground (outside) and step back. The bag will start to expand, and expand, and if all goes well…POP!

Change it up!

This experiment is all about the reaction between baking soda and vinegar. There are many things that can effect experiments like temperature, amount of each item being mixed, the container in which the reaction takes place.

Questions to think about: Will different temperature water affect how fast the bag inflates? What amount of baking soda creates the best reaction? Which size bag creates the fastest pop?

© 2017 Anastasia Borodai

Last Updated: 6/21/17