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Making Caramel Apples in the Microwave

10/30/2017

Every day, we are in contact with a type of energy called electromagnetic radiation. Most of the time it’s in the form of visible light. But did you know that all visible light comprises just a small portion of the electromagnetic spectrum? Radiation is created when an atomic particle (such as an electron) is accelerated by an electric field, causing it to move. This makes a wave in a bundle of light energy, called a photon. The length of these waves classifies the type of radiation produced!

Introduction to Radiation

There are seven sections on the electromagnetic spectrum, ranging from very long wavelengths to very short wavelengths. In this lesson we’ll be focusing on microwaves, but the other types are as follows:

Radio waves have the longest wavelengths on the spectrum, and are used for communication - like radio programs and television! Microwaves come next on the spectrum. Sunlight is comprised of infrared radiation, visible light, and ultraviolet rays. Although we can’t see infrared light, we can feel the heat if we’re close enough to the source! Visible light is comprised of all the wavelengths between 390 and 700 nanometers, which are the colors we can see. It’s the only type of electromagnetic radiation that the human eye can sense.

UV rays are harmless in short periods of time. However, many of us like to go outside in the summer and bask in the sun’s rays. We put on sunscreen to protect our skin from the damage ultraviolet light can potentially cause. The more harmful types of radiation on the electromagnetic spectrum are X-rays and gamma rays. This is why we wear lead when being scanned by an X-ray machine, and why gamma rays are used to destroy some kinds of cancer cells.

How Microwaves Work

Your typical household microwave is able to convert a standard 120-volt electrical outlet into 3000+ volts of power to generate waves of radiation that will heat your food. Inside a microwave is a part called the magnetron, which is what boils off electrons that are whirled around by magnets to create microwaves at a specific frequency. An antenna then transfers those waves into the open chamber where your food is waiting to be cooked.

The microwaves will bounce around the cooking chamber until they penetrate the food and “excite” the polar molecules within your food. In many cases, the polar molecules are water molecules!

When the molecules vibrate, they twist and turn, rubbing up against each other to create friction. This friction is what creates the heat that will cook your food. Because glass, plastic, and ceramics don’t have many of the molecules microwaves look for, the plate or bowl holding your food isn’t cooked. Sometimes the hot food does make the bottom of your plate warm, so always be careful when removing food from the microwave!

One great thing about these appliances is that you don’t have to worry about the radiation damaging anything outside your microwave. Household microwaves have a metal plate with holes in it that are small enough to prevent the waves from escaping, but it still allows you to see the food inside.

Homemade Caramel Apples
Apples are a good fruit to eat all throughout the year, but this sweet treat is great in the fall! Many fairs or spooky events serve caramel apples to their visitors, but why wait when you can make them at home in the microwave? This recipe from AllRecipes.com calls for only a few ingredients: six apples, six craft sticks, some butter, a 14-ounce package of cooking caramels, and two tablespoons of milk.

First, you’ll want to remove the stems and stickers from the apples (twisting is a good way to get the stems off). Press a craft stick into each apple and set aside with a buttered baking sheet.

Using a microwave safe bowl, cook the caramels and milk for two minutes in your microwave. Stir it once and let it cool for a few seconds so you don’t burn yourself. Quickly roll each apple in the caramel sauce until it’s well coated. Then you can place the apple on the prepared baking sheet and wait for the caramel to set. Enjoy!

References:

Fischetti, Mark. “How the Microwave Works.” Scientific American, scientificamerican.com. Accessed on 10/27/17.

Caramel Apples Recipe: http://allrecipes.com/recipe/21130/caramel-apples/

Image Credits:

Siedlecki, Piotr. “Wireless Logo”. Released into the public domain. Uploaded on 10/27/17 from publicdomainpictures.net

Microwave and molecule images property of Discovery Express Kids LLC.

“Coated Caramel Apple”. Released into the public domain under the Creative Commons Attribution 2.0 Generic License. Uploaded on 10/28/17 from commons.wikimedia.org

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Dry Ice and Witch's Brew

10/20/2017

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Have you ever been to a theater production and seen a fog or smoke-like mist spread across the stage? Because it contributes to an eery atmosphere, many schools and production companies use fog machines in many plays and musicals. While commercial fog machines create vapor using mineral oil or glycerine mixtures, you can make your own fog at home with water and a special ingredient: dry ice!

Basics of Dry Ice

Most of us know that we breathe oxygen and exhale carbon dioxide gas. In fact, carbon dioxide spends most of its time in gas form. It makes up 0.04% of the Earth’s atmosphere and is considered a greenhouse gas due to its ability to trap heat.

In the image above, we can see the crystalline structure of solid carbon dioxide (red atoms are oxygen and grey is carbon). Unlike solid water, carbon dioxide doesn’t need to condense into a liquid before freezing. At temperatures below -75.8°C (-109.3°F), carbon dioxide gas deposits directly to a solid. At any temperature above that, the solid CO2 turns directly into gas through the sublimation process.

Many scientists use dry ice to keep their materials extra cold, and it’s also a lot easier to clean up. There’s no liquid left in a container once the ice is gone! We can also use dry ice in beverages instead of solid water - as long as there’s no ice in the cup when the drink is served. You wouldn’t want to come into contact with dry ice, and it’d be especially dangerous to the sensitive skin on your lips.

Uses and Safety Concerns

Dry ice is mostly used as a cooling agent, but it also plays an important role in many other things! When it’s placed in water, sublimation is accelerated and low, dense clouds of smoke-like fog are created. It can also be used by doctors to freeze and remove warts. When the chunk of ice freezes the wart and the skin surrounding it, a blister forms. Eventually, the blister will fall off and take the wart with it! Dry ice can be used as bait to trap mosquitoes, bedbugs, and other pesky bugs because it produces the carbon dioxide that attracts these insects.

One of the most common industrial uses of dry ice is blast cleaning. Pellets of dry ice are shot from a nozzle with compressed air to remove residues on dirty industrial equipment. Using this technique, we can remove ink, glue, oil, paint, mold and rubber. Dry ice blasting can replace sandblasting, steam blasting, and solvent blasting. This is because there’s no leftover residue to clean up, such as sand, water, or other chemicals.

When handling dry ice, one has to be extremely careful. The temperature of ice from water is usually 0℉ (-18℃) as that’s the average temperature of a regular freezer. If you wanted to, you could hold an ice cube or two in your bare hand until it completely melts, but it’d be really cold. However, you don’t want to touch dry ice with your bare skin. Dry ice is much colder...-75.8°C (-109.3°F) to be exact! Any contact longer than a few seconds will freeze your cells and give you a burn-like injury.

Here are important precautions to take when handling dry ice:

Protective clothing. You should always wear some protective clothing when handling dry ice. Some thick gloves, an oven mitt, or even a kitchen towel will be just fine.
Use of a proper storage container. When you’re not using the ice, it should be stored in an insulated container (dry ice is often shipped in styrofoam). Make sure that it’s not airtight, or else the sublimed CO2 gas could build pressure and your container might explode!
Ventilation. You should not to be in an enclosed space with dry ice for too long. After about ten minutes of exposure, the concentration of carbon dioxide in the air can cause problems. If you start to get a headache, breathe quickly, or your fingertips turn blue, that’s a sign that you’re not getting enough oxygen. Make sure to quickly put the dry ice away and immediately remove yourself from that room!

Use Dry Ice to Make a Witch’s Brew!

We know that putting dry ice in warm water will speed up the sublimation process, creating a spooky looking fog. You can show off your knowledge of dry ice with this cool trick! Try adding a couple of pellets to your favorite punch just before serving it to make a spooky beverage - just make sure to remove the ice before you drink it! We recommend searching online for a place to buy dry ice in your local area. Continental Carbonics has 40 locations throughout the United States and Canada. There’s even one here in our hometown of Fargo, ND!

Here’s a modified recipe from The Food Network:

First, you’ll need a block of dry ice, one package of lime gelatin, two cups of boiling water, three cups of chilled pineapple juice, and one 2-liter bottle of any lemon-lime soda or ginger ale.

While you wait for the water to boil, pour the gelatin mix into a large bowl. Slowly add the hot water to the mix, and stir for at least two minutes (or until the gelatin is dissolved). Then you can stir in the cool pineapple juice. Let the juice cool down to room temperature.

When the juice is cooled down, it’s time to add the dry ice! Use some tongs or an oven mitt to pick up the block of ice and gently place it a larger bowl or plastic cauldron. Fill your cauldron with a few inches of warm water - just enough to cover the block of ice. Watch how the ice sublimes before your eyes! Now we can place a punch bowl inside the “cauldron” and on top of the ice. The cauldron will appear to be steaming with a magic brew. Pour your juice into the punch bowl and add the soda. Make sure to mix it well!

The final step is to enjoy your punch - or witch’s brew!

References:

http://dryiceinfo.com/safe.htm

https://www.continentalcarbonic.com/

Image Credits:

Mills, Ben. “Crystal Structure of Dry Ice”. Released into the public domain. Uploaded on 10/17/17 from commons.wikimedia.org

Müller, Robin. “Container for dry ice of the Linde AG company”. Released into the public domain under the Creative Commons Attributions-ShareAlike 3.0 Unported license. Uploaded on 10/18/17 from commons.wikimedia.org

Greyling, Lynn. “Tough Gloves”. Released into the public domain. Uploaded on 10/18/17 from publicdomainpictures.net

“Dry Ice Sublimation”. Released into the public domain. Uploaded on 10/17/17 from commons.wikimedia.org

Anderson, Ralph. “Brew-Ha-Ha Punch”. Released into the public domain. Uploaded on 10/18/17 from myrecipes.com

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All About Vision

10/16/2017

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There are five main methods of perception that we as humans rely on to process information about our environment: taste, smell, vision, hearing, and touch. For this blog, we’ll be focusing on vision, and how our eyes work to let us see our surroundings.

Eyes - Nature’s Camera

Eyes work as cameras for our brains. When an image is presented to the eye, the scene is captured and sent to the brain for processing. To understand this, let’s take a look at the basic anatomy of the human eye.

C: Cornea - The cornea acts as your eye’s outermost lens; sort of like a window that focuses any light entering your eye. It bends/refracts this light so it can pass through the pupil. The sclera (F) is what we call the white of the eye. It is continuous with the cornea and makes up the supporting wall of an eyeball.

E: Iris - The iris is the colored portion of your eye that surrounds the pupil. It can open and close, making the pupil bigger or smaller in response to the amount of light that passes through the cornea.

D: Pupil - The round, black part of your eye is the pupil. It gets smaller (or constricts) in bright light and grows larger (or dilates) in the dark to absorb as much light as possible.

B: Lens - After exiting the pupil, light rays then pass through the lens. The lens can bend and change shape to better focus the light towards the retina. This makes your “picture” as clear as possible.

A: Vitreous Humor - The vitreous humor (or vitreous gel) comprises the majority of the eye. It’s a clear gel-like substance that light has to pass through to get to the retina. Its main function is to give the eye its shape and keep other parts in place.

H: Retina - The back of the eye is lined with a thin layer of tissue called the retina. When we see things, the picture is actually processed as upside-down! In our brains, we turn the image right-side-up again, just like it is in reality. The retina contains millions of tiny nerve cells that we call rods and cones. Cones detect color while rods can detect motion and help us see in dim lighting.

G: Optic Nerve - Once the cells in the retina have converted light into electrical impulses, the signals are sent through the optic nerve to our brains. One interesting thing about our eyes is that information from the right eye is sent to the left half of your brain, and vice versa!

Night and Color Vision

As mentioned previously, there are two kinds of photoreceptor cells in the retina: rods and cones. The rods are most sensitive to light and dark changes as well as shape and movement. These cells contain only one type of light-sensitive pigment. Rods aren’t very good for seeing color. In a darkened room, however, we use mainly our rods, but we are basically "color blind." Because we also use rods for our peripheral vision (seeing objects outside of the direct line of sight), there are more of them in the retina than there are cone cells. There are about 120 million rods in the human retina! Next time you want to look a dim star at night, try to look at it with the edge of your vision and use your rod vision to see the star.

The cone cells are not as sensitive to light as rods. However, each cone is sensitive to one of these three colors: green, red or blue. Signals from the cones are sent to the brain, which then interprets and translates this information into the perception of color. Unfortunately, cones only work in bright light. That's why you can’t see color very well in the dark. So, the cones are used for color vision and are better suited for detecting fine details. The human retina contains about six million cone cells!

Test Your Vision!
Since the the cone cells are not as sensitive to light, it can be very difficult to see colors in dim lighting. Try the experiment below to test your color vision in dim light!

Some people can’t tell certain colors from others, regardless of the light; these people are referred to as "colorblind." Someone who is colorblind wouldn’t have a particular type of cone in the retina, or one type of cone may be weaker than the others. There are many different types of color blindness, but the most common is red-green. People with red-green color blindness see shades of red and shades of green as the same color. This illustration from Edward Scripture’s 1895 book, “Thinking, Feeling, Doing” shows what the American flag would look like to people with different types of color blindness!

Here's an experiment you can do to test your color vision in the dark!

Here's what you will need:

A flashlight
A dark room; either one with no windows, or you will have to do the experiment at night
Some pieces of colored paper
A friend to help you

Here's what to do:

Make sure the room can be made completely dark. Turn on the flashlight, and set it up in one corner of the room
Turn your back to the flashlight in the opposite corner of the room
Have your friend hold up a piece of colored paper. Without seeing the paper beforehand, try to guess the color of the paper in very dim lighting.
If you cannot guess the color, move one step closer to the flashlight and try again.
Keep taking single steps toward the flashlight until you get the color right.
Repeat this process with the other pieces of colored paper. Were any of the color is easier to see in dim light?

Color blindness can also be detected by looking at designs with different colored dots on them, such as the one shown below. Can you see a number?

For more images to test your color vision, visit Color-Blindness.com at the website below:

http://www.colour-blindness.com/colour-blindness-tests/ishihara-colour-test-plates/

References:

“How Your Eyes Work”. American Optometric Association. https://www.aoa.org/patients-and-public/resources-for-teachers/how-your-eyes-work

“Ishihara Color Test”. Color Blindness. color-blindness.com. Accessed on 10/12/17.

Image Credits:

Kratochvil, Petr. “Closeup Eye”. Released into the public domain. Uploaded on 10/12/17 from publicdomainpictures.net

National Eye Institute, Department of Health and Human Services. “Eye Diagram without Text”. Released into the public domain. Uploaded on 10/12/17 from commons.wikimedia.org

“Night Vision Scene”. Released into the public domain. Uploaded on 10/12/17 from publicdomainpictures.net

Montag, Ethan. “Eye Receptors: Rods and Cones”. Released into the public domain. Uploaded on 10/10/17 from commons.wikimedia.org

Scripture, Edward Wheeler. “Thinking, Feeling, Doing”. Released into the public domain. Uploaded on 10/12/17 from commons.wikimedia.org

“Ishihara Plate 9”. Released into the public domain. Uploaded on 10/12/17 from commons.wikimedia.org

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What Are Memories?

10/6/2017

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Do you remember what you ate for lunch yesterday? How about what you had for dinner two weeks ago? You can probably recall the food you ate yesterday, but not something you ate two weeks ago. Why do we remember certain things, but forget others? The ability to recall past events is what we call memory.

The Brain and Memory

Memory is “our ability to encode, store, retain, and later recall information and past experiences in the human brain” (human-memory.net). Emotion is also an important part of memory formation, as it enhances events in order to improve the recollection of experiences that have importance or relevance for our survival.

The process of encoding a memory starts when we are born and continues for the rest of our lives. For something to become a memory, it has to be picked up by one or more of our senses. All memories start off in short-term storage. One example is how we learn to tie our shoes. Once we have the process down, it goes into our long-term memory and we can do it without really thinking about the steps involved!

Our attention span guides us to focus on the most relevant information our brain receives. Surprise is something that grabs our attention like nothing else can. If you’ve ever been told the same story twice, you know that hearing it a second time can be quite boring if you already know the end. Unless it’s really important, most of the information we receive is forgotten and rarely makes it to long-term memory. When we memorize a complex problem, the short-term memory is freed up and the action becomes automatic.

Emotionally charged events are remembered better than those of neutral events. You will never forget some events, such as the joy of the birth of your first child or sibling, or the horror of the 9/11 terrorist attack or the bombing of the Boston Marathon. The stress hormones, epinephrine and cortisol, enhance memory and consolidate memory contents. In evolutionary terms, it’s logical for us to imprint dangerous situations with extra clarity so that we can avoid them in the future.

Emotionally painful memories tend to stick around much longer than those that involve physical pain. That’s why the phrase, “sticks and stones may break your bones, but words will never hurt you,” is false most of the time. Evidence has shown that having your feelings hurt is worse than some physical pain.

Important memories usually move from short-term memory to long-term memory. The transfer of information to long-term memory for more permanent storage can happen in several steps.

Information is committed to long-term memory through repetition — such as studying for a test or repeatedly taking steps until you can walk without thinking — or associating it with something you already know, such as remembering a new teacher Mrs. Williams by associating her name with someone like William Shakespeare.

Types of Memories

By now we know that there are two ways to store memories: short-term and long-term. Short-term memory can be defined as the recollection of things that happened immediately up to a few days. It’s generally believed that about five to nine items can be stored in active short-term memory and can be easily recalled. The more complex memory storage is known as long-term memory. The two main subsets of long-term memory are implicit and explicit. Implicit memory is sometimes called unconscious or automatic memory. It uses past experiences to remember things without consciously thinking about them! One aspect of implicit memory is what we call procedural memory. When we learn how to do things, that knowledge (or motor skills) is stored in procedural memory. Some examples of what type of information is stored here are: ice skating, playing piano, swimming, and writing!

For more information about how long and short term memories form, check out this article about types of memory by Kim Zimmerman at LiveScience: https://www.livescience.com/43713-memory.html

Test Your Memory!

Now You See It, Now You Don't

Let's take a look at your short term memory. First, gather a group of people to test this out on, or enlist the help of an adult to test you and a few friends! Then, get a plate or clear a space on a table. Put about ten small items on the plate (such as an eraser or coin), then cover them with a towel or cloth. Tell your group that you have a bunch of objects on the tray and that you want them to remember as much as they can. Make sure everyone knows that they will only have one minute to view them. Then take off the cover from the plate/table and start the timer for 60 seconds. After the time is up, return the cloth to hide the objects. Have everyone write down all the items that they can remember. Could they remember everything or were there any items that were forgotten by everyone?

Phone It!

Grab a phone book and look up a random number. If you don’t have one at home, most public libraries have them on hand, or you can try checking online. Take about one minute to memorize the phone number. Could you remember the number five minutes later? One hour later? How about six hours later or the next day? If you can remember the number a day later, try to find out how long you can recall it without looking it up again!

Resources:

“What is Memory”. http://www.human-memory.net/intro_what.html. Retrieved 10/5/17.

Hawthorne, John. "Your Memory is an Amazing Thing. Here's How Your Memory Works." https://www.vitamonk.com/blogs/health/how-your-memory-works.

Zimmermann, Kim Ann. “Memory Definition & Types of Memory”. Purch: Live Science. https://www.livescience.com/43713-memory.html

Farouk Radwan, M. “Why do we remember certain things but forget others”. 2KnowMyself: https://www.2knowmyself.com/why_do_we_remember_certain_things_but_forget_others

https://faculty.washington.edu/chudler/chmemory.html

Image Credits:

Royon, Michel. “Human Brain Anatomy in Robotics”. Released into the public domain. Uploaded on 9/24/17 from commons.wikimedia.org

Kelley, Leah. “Close-Up of Pictures”. Released into the public domain. Uploaded on 9/24/17 from pexels.com

Fowler, Orson Squire. “Memory and Intellectual Improvement…” Released into the public domain. Uploaded on 9/24/17 from commons.wikimedia.org

Stachowiak, Kai. “X-Ray Photograph”. Released into the public domain. Uploaded on 9/24/17 from publicdomainpictures.net

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Making Caramel Apples in the Microwave

Dry Ice and Witch's Brew

All About Vision

What Are Memories?

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