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Atoms What is an Atom? What is the smallest thing you can think of? A cell, a virus, or a speck of dust? All of those things are HUGE when you compare them to an atom. Atoms are the smallest unit of matter. Matter is anything that has mass and takes up space. A ball is matter, water is matter, even the air you breathe is matter! What is an atom? (cont.) What would we find if we were to break down a material into the parts that make it up (i.e. microscopic structure)? For example, if you were to take a piece of pure gold, and cut in half over and over again, you would eventually get to the smallest particle that still retains the properties of gold. What would this particle be called? The answer lies within the atomthe smallest building block of matter. Atoms make up each and every object in our natural world. Terms to Know o Atom o Molecule o Solid o Liquid o Gas o Model o Element Atoms Can You Divide a Kiss? Complete the activity described on the following page to help you understand more about atoms. You will need a chocolate Kiss (a chocolate chip, a cracker, or a piece of bread would work too), a napkin, and a butter knife. Atoms Can You Divide A Kiss? Procedure 1. Unwrap the Kiss and place it on the napkin. 2. Use the butter knife to cut the Kiss in half. 3. Cut each half into half again. 4. Continue to cut the Kiss in half until you cut the smallest piece you possibly can get. 5. Answer the Analysis Questions & eat your Kiss! Analysis Questions 1. Can you divide the Kiss forever? Why or why not? 2. If you could keep dividing the Kiss, what would its smallest piece look like? Draw a picture and write a description as if you were looking at the piece through a microscope. 3. In what ways would the smallest piece be like the original Kiss? In what ways would it be different? Atoms How Big Are Atoms, Really? Atoms are so small you can’t even see them with most microscopes. In fact, atoms are so small, there would be too many to count in the Kiss you just divided! Take a look at these examples: A piece of paper is about 10,000 atoms thick. Grains of Sand by Sean O’Flaherty. Retrieved from Wikimedia Commons 6/13/09. A single grain of sand has around 80 million, million, million atoms in it! That is an 8 followed by 19 zeros in one grain of sand! And one drop of water has 2,000,000,000, 000,000,000,000 (that’s 2,000 billion, billion atoms!) Drop of Water by Tanya Puntii. Retrieved from Flickr 6/13/09. How big are atoms? (cont.) The graphite in your pencil is composed of the element carbon. Imagine taking a small piece of carbon and grinding it until it is a fine dust. Each speck of carbon would still have all of the physical and chemical properties of the carbon atom. Now imagine that you could somehow keep dividing the speck of carbon into smaller and smaller pieces. Eventually, you would reach a point where your carbon sample is as small as it could possibly be. Figure 1. Images of individual gold atoms can be seen on the surface of a smooth sheet of gold metal using scanning tunneling microscopy. How do scientists study something they can’t see? They make models.- a tool constructed by the scientist based on all the known experimental evidence about a particular thing. Scientists work with models because reality is complex and difficult. An atom is an example of a system that is both difficult and complex. There are many parts inside of an atom. It is useful to use a model because it helps us understand what cannot be seen with our own eyes. Models are necessary in science. However, you must always remember that a model is only a representation of the real thing. Atoms What Are Atoms Made of? Atoms are the smallest piece of matter that still look like and behave like the original piece of matter (just like the smallest piece of Kiss you could cut still looked like and tasted like chocolate). But atoms are made of even smaller particles called electrons, protons, and neutrons. Atoms The Atoms Family Read the following story about Matterville. Matterville is actually about an atom. As you read the story you will learn about the particles that make up an atom. In the story the particles are referred to as the inhabitants of Matterville: The Atoms Family. Atoms The Atoms Family In the center of Matterville, there is a place called the Nucleus Arcade, where two members of the Atoms Family like to hang out. The first is Perky Patty Proton. Like her sisters, she is quite large with a huge smile and eyes that sparkle (+). Patty is always happy and has a very positive personality. The second family member in the Nucleus Arcade is Nerdy Nelda Neutron. She is large like Patty, but has a boring, flat mouth and eyes with zero expression (o). Her family is very apathetic and neutral about everything. Patty, Nelda, and their sisters spend all of their time at the arcade. Name: Patty Proton Description: Positive Favorite Activity: Hanging out at the Nucleus Arcade Name: Nelda Neutron Description: Neutral Favorite Activity: Hanging out at the Nucleus Arcade Atoms The Atoms Family Around the Nucleus Arcade, you will find a series of roadways, the Energy Streets. These Energy Streets are used by another member of the Atoms Family, Enraged Elliott Electron. Elliott races madly around the Nucleus Arcade on his bright red chrome-plated Harley-Davidson. He rides so fast that no one can be sure where he is at any time. Elliott is much smaller than Patty and Nelda and he is always angry because these bigger relatives will not let him in the Nucleus Arcade. He has a frown on his face, eyes that are squinted with anger, and a very negative (-) attitude. Name: Elliott Electron Description: Negative Favorite Activity: Racing around the arcade Atoms The Atoms Family The first roadway, Energy Street can only hold two Electron brothers at the same time. The second energy street, called the Energy Freeway, can hold 8 Electron brothers. The third energy street, called the Energy Superhighway, can hold 18 of the Energy Electron Brothers but is often Superhighway happy with 8. Can hold 18 electrons Energy Freeway Can hold 8 electrons Nucleus Arcade Contains protons & neutrons Energy Street Can hold 2 electrons Atoms The Atoms Family The morale of Matterville is stable as long as each negative Electron brother is balanced out by one positive Proton sister. For example if there are 10 Elliott Electrons there would need to be 10 Patty Protons. What do you think would happen to the morale of Matterville if one Elliott Electron was kidnapped and taken away from Matterville? Atoms The Atoms Family Challenge 2: What would happen to the morale of Matterville if one Elliott Electron moved to Matterville? Atoms The Atoms Family 1st Verse: They’re tiny and they’re teeny, Much smaller than a beany, They never can be seeny, The Atoms Family. Chorus 3rd Verse: Neutrons can be found, Where protons hang around; Electrons they surround The Atoms Family. Chorus 2nd Verse: Together they make gases, And liquids like molasses, And all the solid masses, The Atoms Family Chorus Chorus: They are so small. (Snap, snap) They’re round like a ball. (Snap, snap) They make up the air. They’re everywhere. Can’t see them at all. (Snap, snap) Atoms Atomic Structure So now that you’ve been introduced to the Atoms Family, let’s review the structure of an atom. Atoms are made of protons, electrons and neutrons. Protons and neutrons are found in the center of an atom in a clump called the nucleus. Electrons float around the nucleus on the “roadways”. Protons have a positive (+) charge, electrons have a negative (-) charge and neutrons don’t have a charge. Proton Neutron Electron Atoms Atom Models Scientists like to make models of atoms to help people understand what they look like. However, the models scientists make can’t really show exactly what atoms look like because atoms are made of mostly empty space. Another problem with modeling an atom is that the parts of an atom are always moving. Atoms Atom Models If you made a model of an atom with a nucleus the size of a pea, in order to make the model represent the actual size of an atom, the pea would have to be placed on the 50 yard line of a football field, and the electrons would be placed all the way outside the stadium! Watch Nova Science Now Atoms http://www.pbs.org/wgbh/nova/physics /atoms-electrons.html