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Curiosity Hacked Matter Badge © Cristen Pantano, September 1, 2015
Badge Overview (what is the intention of this badge? Why are we doing this? Why is it important?)
Through completion of this badge Hackers will understand that everything that surrounds them is made up of atoms and is called matter. Having a basic understanding of atoms, elements, and compounds will enable Hackers to go on to other Science Badges with a clear understanding of how molecules react to create our earth, atmosphere, and all living beings. Understanding matter, means understanding the makeup and chemistry of all things, including ourselves.
Badge Objectives (what info needs to be acquired, retained, and applied for skill/concept mastery?)
By completing this badge, Hackers will understand that matter is anything that takes up space and has mass. They should also understand that matter is composed of atoms, and that atoms make up elements. Hackers will become familiar with the idea that atoms of various elements come together through chemical bonds to create all existing matter in the world and universe. The ultimate goal of this badge is for Hackers to walk away with a comfortable understanding of the chemistry that takes place in their everyday world, and how to apply this knowledge.
Lessons and Activities to support Badge Objectives:
Note: These are activities and resources meant to help facilitate the acquisition and retention of the skill or concept being mastered. They are not, however, mandatory. A dialogue between the Mentor and young hacker should result in a plan to meet the requirements of this badge with the child’s vision as the guide. That may include some or all of the activities below, or it may be designing a new project. The mentor will help to shape the plan so that the child can master the skills through what he or she deems valuable, while still ensuring a comprehensive education in this skill/concept.
What is Matter?
Mini-Activity: Conversation with Hackers about what the word “matter” means to them.
Objective: To have an open conversation with Hackers about what the word “matter” means to them.
Before giving Hackers a definition of matter, ask them what they think of when they hear the word ‘matter.’ Maybe they have heard of the word, but can’t remember the definition. Maybe they have heard the definition but it has no authentic meaning to them. Having this discussion before giving the definition may lead to them being more interested in the actual meaning of the word.
For many of us, when we hear the word matter we think of “stuff.” We think of the things around us that we can pick up in our hands. Maybe we think of the chair we are sitting in or the rocks that we play with. When we hear the word matter, do we think of water? Do we think of air, or possibly our own bodies?
The textbook definition for matter is, “anything that takes up space and has mass.” This is a completely true definition. Everything that takes up space and has mass is considered matter. During the completion of this badge, we hope that your understanding goes beyond the words in this definition. Our cars, toys, books, and yes, our bodies, are all examples of matter; they all take up space and have mass. During the course of this badge you will learn what gives all matter these two properties.
Activity: Observing Matter
Objective: In this activity Hackers will observe the properties of ordinary objects that classify these objects as matter.
Have Hackers look around them and find three objects each that they think can be considered matter. Encourage them to articulate why they think each object is a form of matter. Does it take up space? Does it have a mass? Have a scale available for them to weigh their objects. See if they can come up with ways to determine whether or not their objects take up space/have volume. This could be a great time to introduce how to determine volume by water displacement. Simply, have a bowl or bucket of water handy. Have the Hackers add their objects to the bowl and they can mark off the changes in the water level. This change in water level occurs because the object that they add to the water takes up space and displaces the water. Older Hackers can use small objects and graduated measuring cups to determine the actual volume of their objects. To determine the volume, simply subtract the original volume of water from the new volume once object is added. If the Hackers’ objects have both mass and volume, they can determine that their objects are indeed matter.
What makes matter, matter?
Have you ever held a pencil and thought about what the pencil is made of? What gives the pencil mass? How does it have a form that takes up space? When you hold a cell phone, do you ever stop and wonder what smaller units come together to make up the object in your hand?
Pencils, cell phones, and even apples are all examples of matter. They all have mass and take up space, and they are all made up of millions of smaller units called atoms. Atoms are not visible to the human eye, but they combine with each other and make up everything that we consider to be matter.
Atoms are the building blocks of everything. They are so tiny that we need a special machine called an electron microscope to see them. They are tiny clouds of electricity that come together to make stuff. The concept of an atom is a hard one to grasp, but once we do grasp what an atom is, and how they combine to make stuff, we can understand our world so much better.
A great way to think of atoms is to think of them as building blocks. When you write a word, single letters are coming together in specific combinations. When you build with Legos, different brick types come together to build all sorts of creations; cars, planes, fruit stands, castles and animal hospitals. Each brick is a building block, just like each letter in our alphabet is a building block for words. Atoms are building blocks for matter and come together in all sorts of combinations to build all of the matter in our world.
Activity: Building blocks.
Objective: For Hackers to gain an understanding that individual building blocks come together to create matter.
Have available for Hackers a few different sets of “building blocks.” This could be Lego bricks, small square snap blocks, paper clips, or even tiny balls of clay or model magic. Have Hackers work in pairs and rotate with each type of basic unit. What can they do with just one individual unit? What about four or ten of the same type of unit? Do different unit types allow for different types of creations? Just as each building block comes together to make something new, atoms come together to create matter.
Activity: Building Blocks Part II
Objective: To get Hackers thinking about whether or not atoms are themselves a form of matter.
Have each group go around and examine each type of building block. Do they consider each individual building unit to be a form of matter? If so, why? Do the Hackers think that individual atoms are a type of matter? Why? Once they build something with their units, what gives each unit mass and volume? Hackers should delineate that each individual building block gives matter mass and contributes to its volume
The air that surrounds us is essential for life as we know it. We breathe it in every second to help our bodies function. It moves and creates our weather, which helps create and maintain all of the earth’s ecosystems. If we move our hands back and forth we can feel it, even though we can’t see it. When air moves quickly, we feel it as wind. But is air matter? Does it have mass and take up space?
Activity: Is Air Matter?
Objective: For Hackers to design an experiment to determine whether or not air is matter.
In order for anything to be matter, it must have mass and volume. Therefore, the Hackers should be involved in a discussion about how to test whether air is indeed matter. The Hackers should be encouraged to realize that somehow they would have to determine whether or not air has mass and volume. Once they realize what needs to be tested, guide them in designing the following experiment; Give pairs of Hackers two balloons, string, a ruler, tape, and have an air pump available. See if Hackers can come up with a way to test whether or not air has mass. A great hint to give them is to use the ruler as a scale. Give Hackers at least ten minutes to discuss how they can figure this out. This will be a hard exercise, and that is okay. The goal is to get them thinking about experimentation. Walk around and chat with them and with your guidance, try to get them to the point of designing something like this:
Once each group has come up with a few ways to test if air is matter, show them the following video and conduct the experiment. Or, you can help them set up the experiment without watching the video and have them predict what will happen to the yardstick when one balloon loses its air.
This experiment will allow them realize that air does indeed have mass. The question of whether air has volume can also be answered with this exercise! Ask Hackers how. If the balloon expanded when filled with air, then air takes up space. While this is a fixed experiment, really encourage Hackers to try and determine what questions need to be asked and how to ask them rather than just giving them a set of directions.
If Hackers come up with additional ways to determine whether or not air has mass, let them go with it. It doesn’t have to be perfect. Just get them thinking!!!! A great, and super fun, activity is to give them trash bags and send them outside. Can they think of a way to show that air has volume? Could they bring out string and their garbage bags and redesign their indoor experiment to determine whether or not air is matter?
What is an atom anyway? How can atoms become stuff?
Earlier we discussed that atoms are the basic building blocks of matter, but what exactly is an atom? An atom is the smallest unit of a chemical element. This means that if you were holding a piece of gold in your hand, you would actually be holding millions of identical tiny units and each unit would be an individual gold atom. When we did our basic unit exercise, each unit represented an atom. In real life, all matter is made up of individual atoms that come together to make matter.
An atom isn’t an imaginary or elusive “thing.” An atom is a real and tangible entity. In fact, an atom has mass and takes up space, therefore an atom is also considered matter! If we think about it, that makes sense. If atoms didn’t have mass and take up space, how could they be the basic unit of all matter? If a brick house was made of bricks with no mass or volume, would the would the house take up space and have mass?
An atom is made up of three even smaller particles; protons, neutrons, and electrons. Protons and neutrons are clustered in the center of the atom, in its nucleus. Electrons orbit around the nucleus. Protons are charged particles, they have a positive charge. Neutrons have no charge, and electrons have a negative charge. Electrons swirl in areas called shells, or energy levels. Each shell can hold a certain amount of electrons. The first shell can hold two electrons, the second shell can hold eight, and the third eighteen. The number of protons in each different type of atom is equal to the number of electrons. For example, carbon has six protons in its nucleus, and six electrons in its electron shells.
Most matter is made up of a combination of more than one type of atom. The pencil that you write with, the water that you drink, and the food that you eat are all compounds. When matter is made up of only one type of atom, the matter is called an element. We will discuss both elements and compounds in more detail later on.
The idea of an atom can be confusing and hard to grasp at first. There is nothing wrong with keeping it very simple. Mastering the concept of atoms and basic chemistry can take years to fully grasp. The goal of this badge is for Hackers to get a deeper understanding of these areas, but mastery is not necessary. Planting the seed of knowledge and a love of science is more important at this time.
Activity: Build an atom mobil.
Objective: To allow Hackers to get creative while learning about the structure of atoms.
Have a stack of cards available with an amount of protons and neutrons given. Give each Hacker a card and have them build an atom based on this information. They should be able to extrapolate the number of electrons based on the number of protons. Have a chart up with the number of electrons per shell. Provide fun materials such as construction paper, pom poms for protons and neutrons, pipe cleaner and beads, model magic, yarn, buttons, anything for Hackers to build a nucleus and have the electron shells swirling around. Encourage them to decorate shells and atomic particles with glitter glue or other fun materials. Have materials such as sticks available so they can make a beautiful atom mobil. Have a chart or printout available for them to be reminded of the number of electrons per shell.
Just as the basic building blocks came together to make your creations in our earlier activites, atoms come together to make matter. When the same type of atoms (meaning atoms with the same amount of protons, neutrons and electrons) come together, we get elements. Elements are a type of matter that contain only ONE type of atom. Many elements are most commonly found in nature bonded to atoms of another element. We call these elements, reactive. This means that they easily bond with different atoms. However, plenty of pure elements are found in nature and are used by humans. Think of iron, silver, and gold; these pure elements have been used by humans throughout our history.
There are 98 elements that occur naturally. This means that there are 98 different types of atoms in our universe. These atoms differ from each other because they have different amounts of protons in their nucleus, and different amounts of electrons in their shells. Some atoms, such as sodium, are what we call very reactive. They like to seek out and spend time with different types of atoms to form compounds, and they are rarely found in elemental form. However, many types of atoms such as gold, silver, and iron, enjoy the company of atoms just like themselves and are commonly found in elemental form.
Believe it or not, the elements that we have on earth came from space. It is believed that right after the Big Bang atomic nuclei formed. The first atoms that formed were hydrogen, helium, and lithium. Once stars started forming, the massive heat and energy in the stars brought atomic particles together and the other elements were formed. When stars die, and explode, they spread these elements into space. This sounds crazy, but it is true. Everything in the universe is made up of the same types of atoms that our earth, and our bodies, are made with. In fact, the very atoms in our bodies came from space.
Activity: Element Creation Flip-book
Objective: For Hackers to have fun and get creative while thinking about how the elements came to earth.
Provide materials for Hackers to create a flip-book, diorama, comic, poem, anything they chose to depict their vision of how elements came to earth. Hackers can go further and create a timeline of atoms and elements coming to earth, creating life, and how humans have used elements throughout history.
Phases of Matter, Elemental Solids
When we think of elements, we may think of things such as gold, or maybe we think of oxygen. You probably know that at room temperature gold is a solid and oxygen is a gas. Solid, liquid, or gas refers to the phase of matter.
You probably know that phases of matter means whether matter is a solid, liquid, or a gas. What we are really talking about when we discuss phases of matter, is how closely the atoms that make up the matter are arranged or packed.
In solids, the atoms are very close together, we say that they are densely packed. This phase of matter will not flow and is rigid. Solids have a definite shape that can only be changed by physical force. For example, cutting a piece of bread or breaking a stick in two. The shape has changed, but the arrangement of atoms in each new piece is still the same, Thus, you still have a solid. In liquids, the atoms move and flow over one another. The matter does not have a distinct shape, but can fill a container. In gases, the molecules are very far apart and free flowing. You can move your hand through a gas.
How does matter shift from one state to another? It’s all about energy! When atoms are packed close together like they are in a solid, they are sluggish and don’t move much. When energy, in the form of heat, is added the atoms get more energetic and start moving around. Think of that first burst of warm air and sunshine in spring, we all move from being packed and sluggish indoors to running around outside with lots of energy. That’s kind of like what happens when atoms in a solid get more energy and become a liquid. The addition of even more heat to a liquid gets the atoms moving even more, to the point where they don’t want to be near each other. Think of when it’s really hot and don’t want anyone touching you. That’s what it is like when matter goes from liquid to a gas.
Activity: Building a crystal solid
Objective: For Hackers to build with their own hands a 3D crystal structure to learn how atoms pack together to form solid elements.
In elemental solids, the atoms are packed so tightly together that they can’t move freely, they can only vibrate. The tight packing of atoms gives solid elements and matter their shape. Solids have a regular, repeating structure of atoms, known as the crystal structure.
Using toothpicks, polymer clay and Model Magic have Hackers create a crystal structure of an element. They can create their own pattern, and their own element. Or, they can search the web and recreate the crystal structure of an element of their choice.
The pattern should repeat! The toothpicks act as bonds between the atoms, the model magic can be the atoms. Kinnex, or even Tinker Toys, could also work well in this activity.
Stress to Hackers that when they are holding solid elements, they are holding atoms packed together in a very specific way. There is nothing random about an element. When they hold a piece of metal, they are holding the result of millions of tiny atoms packed densely together in a repeating, and specific pattern.
The Periodic Table
Chances are, you have seen the periodic table many times. At first glance it can look like a checkerboard, some sort of cross word puzzle, or just a bunch of blocks with letters and numbers in them. Believe it or not, the periodic table is a masterful organization of the elements. More specifically, it is a table that organizes the elements based on their properties. Since atoms make up elements and give them their properties, you can think of the periodic table of the elements, as the periodic table of atoms.
Atoms appear on the table from left to right based on the number of protons in their nucleus, this is their atomic number. Atoms in the same vertical columns, or group, have the same number of electrons in their outermost shell. Groups are also sometimes considered families. Atoms in the same horizontal row have the same number of electron shells, each of these rows is called a period. The atoms in the first row have one shell, the second row two, and atoms in the third row have three electron shells. Study of the periodic table can be a badge in itself, in this badge we want to stress that atomic structure gives elements their properties. Hackers should understand that the arrangement of elements in the table is based on atomic structure which determines properties of elements. Details on the arrangement of elements in the periodic table are available in the Matter Booklet.
It is up to Hackers how deep into periodic table organization they want to delve. If it is a younger group, it is ok to just introduce the table as a way to arrange atoms.
Mini-Activity: Select a few atoms from the table and draw them based on the information gained from the periodic table. Should be done with Guild Leader leading this activity on a white board.
Objective: To get Hackers used to deriving information about atoms from the peridoic table.
Electrons per shell: Two in the first, eight in the second, eighteen in the third
Examples to use:
Carbon: Atomic number, six, therefore has six protons and electrons. Second row of periodic table, therefore two electron shells.
Oxygen: Atomic number, eight. Also, two electron shells. http://thumbs.dreamstime.com/z/atomic-structure-oxygen-d-render-32273780.jpg
Sodium: Atomic number, 11. Third row of periodic table, therefore, three electron shells.
Learning about the Elements
While we are familiar with the names of many elements, we are usually thinking of them when they are bonded to different atoms to make a compound. For example, when we think of sodium, we think of sodium chloride or table salt. We don’t think of sodium as a sliver, soft, metal. But in elemental form, it is! Learning about the characteristics of pure elements can be fascinating, fun and and lead to a greater understanding of how they are used in our world. Elements with similar atomic structure have similar properties, and are characterized into families. These families are sometimes grouped in vertical columns on the periodic table, other families appear in clusters on the periodic table.
Remember, when you are learning about element families, you are learning about atoms. For example, one element family that we are all familiar with are the alkali metals. Lithium, sodium, potassium are all part of this family. Every element in this family has only one electron in its outer shell, this makes the atoms very reactive. When we say that an atom is reactive, we mean that it will seek out other atoms to form bonds. Elements in this family are so reactive that they are always bonded to other types of atoms in nature. The metals in this family have similar properties because their atoms are similar.
Activity: Learning About Elements That We Use Everyday
Objective: For Hackers to learn about how an element is used in our world to make the matter that we use every day.
Did anyone in your house use a computer today? Or a cell phone? Electronics are of course a type of matter, and are made up of atoms. One element that is very important for electronics to work is silicon. Silicon can conduct electricity at very high temperatures, and can also be used to control the flow of electricity in electronics. It is used to make computer chips and circuits. Your iphone and ipad work because of the properties of silicon atoms! Many other elements are used by humans every day. Each element that is used by humans is useful in it’s own way based on its atomic properties and chemistry.
Have Hackers work in groups of two. Have them choose an element or compound that they are interested in learning more about. Perhaps they know that cars are made of steel but don’t know why. What is steel anyway? Maybe they want to learn more about why silicon is so important in electronics, maybe they want to know what elements make up the earth’s crust. Perhaps they want to learn more about what elements make up their body and what role they play in sustaining their health. Have available books, pamphlets on elements, and internet access. Encourage the different groups to pick different elements. Have the groups share what they have found out about their with the group. DK, Usborne, Scholastic and National Geographic have great books about elements that would be great for this activity. They are available at most public libraries.
Activity: Why do metals conduct electricity? Create a lemon battery with two metals.
Purpose: To teach Hackers how and why metals can conduct electricity.
Metals make up 75% of the elements. One property of metals is that they can conduct electricity. Why? First make sure all Hackers know what electricity is: the flow of electrons. This flow of electrons creates energy and allows work to be done. Metals can conduct electricity because in metallic bonds, the outer electrons are free and can be removed from the atom. Once removed, the electron will travel from atom to atom. A great visual for this is to hand one Hacker a lemon. The lemon is an electron. He now has more negative charge than the atom (Hacker) sitting next to him. The electron will move to this more positive atom (Hacker). Have the Hackers transfer the electron (lemon) from atom to atom (Hacker to Hacker.)
Metals can conduct electricity because their outer electrons are not in a bond. The electron can be pushed out by a force. In the following experiment, the acidic lemon juice reacts with metal in the nail and frees its outer electrons. The electrons gather on the nail. Once a circuit is made between the nail and the copper penny, the electrons will travel from the nail to the penny.
This first video provides a great explanation for the science occurring in this experiment. Remind the Hackers that the metal is able to readily give up electrons to get the current going. This is why metals can conduct electricity and not something like a wax where all of the atoms are bound in strong bonds.
The second video is a great instructional for the Guild leader. https://www.youtube.com/watch?v=GhbuhT1GDpI
Our books, our food, our bodies. Are these things matter? Of course! Are they pure elements? No. They are made up of many different molecules and compounds. Both molecules and compounds contain more than one atom, and compounds contain more than one type of atom. The ability of different atoms to combine and make new compounds with new properties is what makes our world, and the matter that fills it, so very interesting!
Understanding how, and why, atoms of different elements come together to make compounds is fundamental to understanding the world around us. Our very own bodies are a collection of compounds made from carbon, oxygen, hydrogen, phosphorous and nitrogen atoms. The fact that atoms can combine to make compounds gives the world life. The air we breathe, the water we drink and the food we eat, all exist because atoms can combine and create new compounds with a plethora of properties.
Just like individual letters of the alphabet come together to make words, atoms of different elements can come together to make compounds. The twentysix letters of our alphabet can combine in what seems an almost infinite way to make up the words of our language. Each combination of letters has its own look, meaning, and sound. Each combination of atoms also has its own unique set of properties.
Activity: Making compounds.
Objective: For Hackers to visualize how the combination of different atoms can create new forms of matter with new properties.
Have cut out letters, or letter magnets on a table. Discuss how the addition of one letter to a word can drastically change the meaning, sound, and look of the word. For example, have kids put together letters to make the word, “pin.” Discuss the meaning of this word. Have them add an “e” to pin. Discuss what happened to the word. Repeat with, “can.” Then, have Hackers find letters for a word of their choosing. Ask them to recombine some of those letters to make a new word. This is what happens with atoms. Atoms combine in a VERY specific way to create compounds. When atoms combine the resulting compound has completely different properties than the individual elements. The addition of a new atom, or a new combination of similar atoms, can create a completely new compound. For example, both water and hydrogen peroxide are composed of hydrogen and oxygen atoms.
Water, H2O Hydrogen Peroxide, H2O2
Have Hackers work with a molecular model kit and have them build water and hydrogen peroxide models. Discuss how the addition of just one additional atom to water can drastically change the properties of the compound.
Why and how do atoms combine?
Earlier on we talked about how certain atoms are more reactive than others. This means that some atoms are much more interested, and capable, of combining with other types of atoms to make compounds. But, why? Basically, it all comes down to what makes an atom comfortable, and what doesn’t.
Atoms like to have full outer electron shells. They are most calm and pleased when their outermost electron shell has as many electrons as it can hold. This makes them happy and relaxed. Atoms with outer shells that aren’t full look for other atoms that need, or are willing to, give up or share electrons. Most atoms that are involved in chemical bonds with atoms of other elements are looking to fill their outershell with eight electrons.
If an atom has seven electrons in its outermost shell, and the shell can hold eight, that atom will not relax until it finds a way to get another electron to fill the shell. Atoms can do this by sharing an electron with an atom that has one to spare, or by accepting an electron from an atom that is willing to give up an electron to become more stable. Some atoms may have a full shell of eight electrons followed by a shell containing just one electron. The atom will gladly give up that one electron to be left with a full shell of eight atoms.
When atoms share electrons in a way that gives both atoms a full outer shell, we say that they are covalently bonded. When one atom gives up its extra electron to another atom to achieve a full outer shell, the two atoms become charged and are attracted to each other. This type of bond is called an ionic bond.
Activity: Build a water molecule.
Objective: To have Hackers to build models of atoms and see how and why they combine to fill their outer shells. These combining atoms create new compounds, which are new forms of matter!
Have available to Hackers print outs of how many electrons are needed to fill each shell, and the atomic number or structure of hydrogen and oxygen atoms. Have groups of Hackers build these atoms as in earlier exercises with craft materials, remember that two hydrogen atoms are needed per oxygen atom! They should see that oxygen needs two more electrons to fill its outer shell, and that each hydrogen has one electron in a shell that needs two electrons to be full. How can these two atoms come together to fill the needs of all the atoms involved?
After Hackers try to workout how two hydrogen and one oxygen atom come together to form water, discuss with them the covalent nature of bonding in water. Two hydrogens share their electrons with an oxygen atom, to create two electrons in the outermost shell for the hydrogen atoms, and eight for the oxygen atom. Covalent bonds are very strong and take a lot of energy to break.
NOTE: In nature, hydrogen actually exists as a molecule of two hydrogen atoms, H2. Oxygen also exists in nature as a molecule of two oxygen atoms, O2. So if you see the actual reaction written out, it will look like 2H2+O2…… 2H2O
Activity: The bonding game.
Objective: For Hackers to have fun and see how, and why, atoms bond to form common compounds.
Have available cards with the structure (distribution of electrons) of the following different atoms on them. May be also useful to have a chart of electrons per shell.
Sodium Chloride Magnesium Oxygen 2 Hydrogens Oxygen Calcium Chloride
Each Hacker is given a card and holds it on their chest. They have to go around the room and find the atom that is best suited for them to bond with. Each atom wants a full in their outer shell. They can do this by giving up electrons, or by sharing them. When the two atoms bind, they make a molecule. Molecules made with the list given:
Sodium Chloride Magnesium Oxide Water, H2O Calcium Chloride
Discuss how hectic the room was when each atom was looking for those electrons to fill their outer shell and how things calmed down after the bonds were made! Also point out how new, interesting, and useful compounds were made as the atoms bonded. Atoms bond to get to a lower energy state. They are calmer and happier with those full outer shells. Luckily, all that bonding creates the fantastic world that we live in!
Physical Properties of Matter
How would you describe yourself to someone who has never seen you? Tall, short, brown hair, blue eyes, freckles, a mole, perhaps a scar? Just as every person has unique characteristics, all types of matter from atoms to compounds have their own unique traits. When we describe the traits or characteristics of matter, we are describing their properties.
Go around the table and ask Hackers to describe a type of matter that they see. What types of words do they use? Color? Size? Texture? These are called physical properties. Physical properties describe matter without changing their atomic make up. Meaning, they describe a form of matter without having any chemical bonds made or broken. If a chemical bond is made, or broken, a new type of matter is formed! Physical properties describe matter without changing anything about the matter.
Some examples of physical properties are size, shape, color, texture, boiling point, freezing point, solubility, and whether or not the matter can conduct electricity.
Activity: Use physical properties to determine whether two compounds are the same or different
Objective: Hackers will see that while sugar and salt look similar, they have different physical properties because each compound is made up of different atoms that are joined if different types of bonds. By looking at sugar and salt under a microscope, testing their solubility and determining whether or not they can conduct electricity, Hackers will decide whether or not these two seemingly similar crystals are the same or different compounds.
Scientist use physical properties to distinguish one type of matter from another. Let’s look at sugar and table salt. They both are white crystals, they look very similar. How can we distinguish these two seemingly similar substances from each other? We can test and see if they have the same physical properties!
Have two bowls out, labeled A and B. Have salt in one and sugar in another. Have Hackers look at each under a microscope and test the solubility of each in cold water. Have them work in pairs and take notes of their observations.
Conductivity is a physical property. Have Hackers conduct the basic squishy circuit exercise with playdough made from sugar, and salt to (each playdough labeles A or B) to determine if both compounds conduct electricity. The main point to get across is that salt, and not sugar can conduct electricity and that this property can distinguish the two very similar seeming compounds from each other. Why can salt conduct electricity and sugar can’t? Salt is held together by an ionic bond, rather than a covalent. When salt dissolves in water, the sodium and chloride atoms separate and become charged. This charge allows them to conduct electricity. Sugar is held together with very strong covalent bonds between carbon, hydrogen and oxygen. The atoms stay covalently bonded when dissolved and don’t have the ability to move an electrical current.
Activity: Making and comparing salt and sugar crystals
Objective: To reinforce that different compounds, while they make look similar to the human eye, are made up of different atoms and combine in very different ways.
Usually when we hear the word “crystal” we think of things like crystal rocks and salts. Crystals such as those found in rocks and our table salt, are solid compounds with a specific repeating, ordered, three dimensional pattern of molecules. Since different types of crystals contain different types of atoms bonded together, their physical structures are different.
Table salt is a crystal made of sodium and chloride. Sugar is a crystal made of carbon, oxygen and hydrogen. They look very similar when we look at them with our eyes. Do you think they have the same crystal structure? Why or why not?
Have Hackers start making these in the lab and allow them to take them home to observe and keep. Provide food coloring so that they can color their crystals. Have some sugar and salt crystals on hand and have the Hackers look at them individually under a microscope. Do they look the same or different? Why?
The salt and sugar crystals differ because the salt and sugar molecules differ! Salt is made up of units of bonded sodium and chloride to form a salt molecule. Each sugar molecule is made up of twelve carbon atoms, eleven oxygen atoms and 22 hydrogen atoms. Obviously, with such different make-ups, these two molecules are going to pack very differently into their solid forms. This is a great exercise to demonstrate how different combinations of atoms lead to such a variety of matter in our world.
Some of the most interesting and versatile compounds in our world are polymers. Polymers are very large molecules that are composed of repeating units. Each unit is a compound itself, and bonds to another similar unit creating a long chain. At first, you may think that you aren’t familiar with polymers, but I can guarantee that you are. Your hair, your toothbrush, silk, wool, tree sap and your very own DNA are examples of polymers.
To get an idea of what polymers look like, simply grab a pile of paper clips and link them into a long chain. You now have a flexible and strong new form of matter made from a repeating until Remember, the repeating unit here isn’t one atom! It’s a compound of many atoms. Most polymers in nature are made from combinations of carbon, hydrogen and oxygen.
Humans have developed many polymers that have become commonplace in our lives. Ever hear of plastic? Plastic is a synthetic polymer! Plastics consist of long chains of repeating carbon and hydrogen units. Yup, just a carbon and some hydrogens bonded to each other in chains of thousands, millions, of repeating units gives rise to the incredible variety of plastics in our world. But, how? One property of many plastic polymers is that once made, they can be melted, molded and then cooled again. How is this useful to our world?
Activity: Paper clip polymers
Objective: For Hackers to visualize polymers
Have out a pile of large silver paper clips. Each paper clip represents a monomer. Have Hackers link the monomers into long chains. How are the physical properties of this long chain different than the one monomer? have them make two chains.
Then bring out small colored paperclips. Have Hackers link one chain to another with the small paper clips. This is called cross linking. How have the properties of the chains changed?
Activity: Crosslink a Polymer and make a bouncy ball!
Objective: For Hackers to see how crosslinking a polymer in chemical reaction can create a whole new type of matter with new properties. This hands on activity is also an example of a chemical reaction.
Procedure: I used this video as a guide while beta testing. The crosslinking reaction is very fast and remind the kids that the matter just went through a chemical change.
Note: Glue is a polymer. When mixed with Borax, a chemical reaction occurs and the Borax crosslinks the glue making a new form of matter, which resembles rubber.
Activity: Invent a polymer
Objective: For Hackers to get creative and come up with a new polymer that can be useful to society. No need to come up with the chemical formula here! Hackers can use pipe cleaners, Kinnex, clay, a painting, graph paper, toilet paper rolls, legos, whatever they want to make a model of a new polymer. What is the benefit of their new polymer to society? The structure should have repeating units and have a use for society.
Plastic and nylon are two forms of polymers invented by humans, and while they have downsides, they are very common in our society. Can you think of a new polymer that would be useful to our society? Or any new form of matter that would help enhance our world?