Physical Science Lessons
Materials Do Matter
• Types of Matter...Does it matter? You may have asked that question yourself from time to time. Scientists, on the other hand, ask a different question: what is matter? Matter is everywhere around us. Things we see and use throughout the day are made of matter. In fact, there is so much matter around us, it can be hard to think of things that are not matter. In this lesson we will discuss not only what it means to be made of matter, but different ways to describe and organize matter as well. By the end of this lesson, you will better understand that matter really does matter!
• States of Matter...Matter can exist in different states, or phases. For instance, we have all seen water in its different states: as a solid, or ice; a liquid, which we drink; and as a gas, which is water vapor like our breath on a cold day, or as fog. You have probably even seen water as it is going through these phase changes. When water boils, it is transforming from the liquid state to the gas state. When water freezes, it is transforming from the liquid to solid state. When ice melts, it is transforming from the solid to the liquid state.
Matter in Motion
• What is it and Where is it Going?...People who study pushes and pulls are called physicists, and they are very good at explaining how things move. We use pushes and pulls, or forces, to help us with fun activities like skateboarding, drag racing, or traveling.
• If it Goes Up......There is a force that pulls objects, even your body, toward the center of the Earth. This same force keeps the Earth in its path around the sun and keeps the moon going around the Earth. One of the first scientists to study this force was Sir Isaac Newton. This lesson will review the story of the famous apple falling on his head. We know that gravity keeps us from floating into space, but there are many more ideas about gravity that are fun to learn.
• Man's Motion Modifications...When we think of machines, we may think of big objects with many moving parts. If we take these large objects apart, however, we would see that many big machines are combinations of smaller ones. These simple machines help us in many daily activities, such as when we do chores, build buildings and raise the flag at school, just to name a few. We would not be able to ride in a car or an airplane without simple machines. Many different kinds of careers can involve simple machines. Products we use every day are mass produced along assembly lines. These assembly lines contain many different types of simple machines, such as pulleys and inclined planes. Engineers and inventors keep these assembly lines running smoothly and think of new ways to make them work better. Imagine what life would be like if you had a job to do, and some key simple machines were missing.
Charging Into Energy
• Use It or Store It...Energy: it is everywhere. As long as the sun continues to shine, there will always be energy. The sun, indeed, is the primary source of energy on Earth. Energy is the ability to make matter and waves move. Energy is present in our homes and schools, our bodies use it to run and jump, the songs we hear on the radio exist because of energy. Energy keeps us warm in winter and provides relief in the summer. Energy has been around as long as the universe has existed. Throughout history, humans have learned to use the various forms of energy to perform work. The first fires provided basic necessities such as heat and light. Today, we can use different sources of energy for many purposes: to build skyscrapers, fly around the world, and even travel to the Moon and beyond. The amount of energy never disappears, and it is never newly created. The form and location of the energy is what changes. This can be a strange concept to believe, but it is true! Energy is the basis for everything that occurs; without it, there would be no light, no cars and trucks, no televisions and computers, and no life.
• A Heated Topic...The sun provides all of the energy that exists on Earth. Plants, animals, and humans use energy for growth. We use energy to stay safe and comfortable and to move objects. Energy is what moves the Earth on its axis. Without the sun’s energy, Earth could not exist in the way that we know. Heat is one form of energy that can be useful. We need heat energy to keep us warm, especially in cold weather. Most homes use electricity or natural gas for heat, both of which come from non-renewable resources. The sun is an immense source of energy and a renewable resource. Though solar power is not yet widely used, it is on the rise. Geothermal power, or the heat that comes from inside the Earth, is another form of heat energy.
• Making Waves...Energy travels in wave-like motion. We can detect energy when it is in specific forms that travel in waves, such as electricity and sound. Electricity is simply energy that is charged. Electrons are excited and cause an electrical output. The electrical charge can be used in a variety of everyday ways such as driving a go-cart, watching a movie at the theater or cooking a meal. Sound is the vibration of the particles of some sort of matter. Sound travels by pushing and pulling the particles, much like how a wave travels in a slinky if pulled and then released at one end. Sound energy is present in both living and non-living entities.
• Flip the Switch...We rely upon energy, specifically electricity, to go about our every day lives. At any given point during the day, we likely are using electricity in some way or another. Watching television, surfing the Internet, playing basketball in the school gym, traveling in a car, preparing dinner, and a visit to the mall all require electricity. To obtain this electricity, we simply push a button or flip a switch. If you have ever wondered what really happens underneath that button and behind that switch, you will be amazed to discover the intricacy. It relies on a precise arrangement of circuits to allow for the most efficient delivery of electricity to the switch. We do not usually see these circuits because they are hidden behind walls, under floorboards, and inside appliances. The flow of electrons, which is what electricity is, never stops. However, we can manipulate the way that these electrons move by creating elaborate circuits. While these complex electrical systems may look complicated, they are actually easy to decipher if you know a few basic terms and properties about electricity.
• An Attractive Process...Magnets – you have probably played with them since you were a young child. Many of your toys contain magnets and when you bring home a good report card or a beautiful painting, you may have used a refrigerator magnet to hang it on the fridge. You may wonder how magnets really work, or how they “stick” to certain surfaces, but push away from others. We have to look at the tiniest parts of the magnets to understand better what is happening. Magnetism is the result of motion by billions and billions of electrons, which are negatively-charged subatomic particles. Just like planets in our solar system revolve around the sun, electrons both revolve around the atom's nucleus and rotate on their own axes. This movement creates a magnetic force field between the electrons. As a result, each electron takes the properties of a magnet: attractive and repulsion forces.
Energy and Motion
• The Nature of Science...Biology, chemistry, and physics are three major scientific fields. There are sub-disciplines that overlap these fields, such as physical chemistry, biophysics, and biogeochemistry, but all of these disciplines have one thing in common. They all use the scientific method as an approach for observation, hypothesis, experimentation, and theory. The fields of technology and engineering apply scientific theory in practical ways to benefit society. They require a common language of units, mathematical equations, and visual graphs. The standard units of science and engineering create the International System of Units (SI). Some countries such as the United States continue to use Imperial (British) units in everyday life.
• Motion and Speed...The revolutionary ideas of Galileo and Newton have propelled humanity into unequalled technological advancement over the past several hundred years. Consider the Olympics games, in 776 BCE, centuries before Aristotle. Our understanding of the physics of motion has given athletes an edge as they throw the javelin or race “chariots.” Imagine what our modern world would be like if we still believed in a geocentric universe, if NASA assumed that spacecraft would continue to travel only by maintaining booster rockets, and if Boeing and McDonnell Douglas had no means of balancing forces and understanding gravity and air resistance when building its airplanes.
• Energy...Our current understanding of physics relies on the assumption that the total energy in the universe is constant. That is, from the beginning of the universe, it has neither gained nor lost energy. Energy can be transferred and transformed, however, from one form into another. The energy of motion can transfer from one object to the next through collisions. Energy can also be transferred through electromagnetic radiation such as light and radio waves as well as through chemical and nuclear reactions. Einstein and other theoretical physicists during the early twentieth century showed us that matter itself is a form of energy and quantified energy on atomic and subatomic scales.
• Forces...NASA now proposes to resume manned space flight to the moon and Mars within the coming decades. Our recent knowledge of solar flares and cosmic radiation has brought to question the feasibility of safe human travel beyond the Earth’s protective magnetic field. Other than radiation exposure, however, the basic physics and technological challenge of how to get a several-hundred-ton spacecraft beyond Earth’s gravity and propel it to Mars and back in a reasonable amount of time remains similar to research in the 1960s. In fact, these questions began half a millennium ago, led by the physics and mathematical theories of scientists and philosophers such as Galileo, Johannes Kepler, and Isaac Newton, all studying motion and force. Although a mission to Mars would necessitate knowledge beyond the realm of Newtonian physics to include electromagnetic forces studied by James Maxwell and nuclear forces explained by Albert Einstein, we will focus on Isaac Newton’s Laws of Motion and the Universal Law of Gravity during this lesson.
• Work and Machines...Machines allow us to perform work more efficiently. Simple machines such as pulleys, levers, and wheels have led human civilization to accomplish seemingly impossible feats, from building the pyramids of Egypt to modern day skyscrapers and dams. More complex machines such as clocks, computers, and automobiles allow us accurately to tell time, perform detailed computations, and travel long distances. Recall that the definition of work is force multiplied by distance. Energy is the ability to perform work. Machines use energy to provide the necessary force to simplify our work.
• Thermal Energy...Molecules move in random motion. The phrases heat, thermal energy, and internal energy all describe the kinetic energy of molecules. Temperature is a measure of this energy. Higher temperatures correspond to greater molecular kinetic energy. The Laws of Thermodynamics describe the behavior and transfer of heat. In general, heat transfers from hotter to colder objects. Types of heat transfer include convection, conduction, and radiation.
Electricity and Energy Resources
• Electricity and Magnetism...Electricity and magnetism are everywhere in our lives. Electric alarm clocks wake us up in the morning, electric stoves cook our food, and electricity lights our homes. Electrical energy is created by electrons are flowing through a conductor. This flow of energy must go through a closed path, or circuit. If that circuit is broken -- for instance by a light switch that is turned off -- the electrons cannot flow and no electricity is produced. The light does not turn on. Electricity can also be used for magnetism, or electromagnetism. We have all seen magnets on refrigerators, but when combined with electricity, electromagnetic devices serve numerous functions, including in motors for toys, washing machines, and even electric toothbrushes.
• Radioactivity and Nuclear Reactions...You have likely seen pictures of the “mushroom cloud” that results from an atomic bomb. What kind of forces are at work in such a destructive device? Believe it or not, the reactions that cause such a violent reaction take place at the atomic level. Atoms are so small that if you lined fifty million of them in a row, they would measure about a centimeter. An atom is the smallest part of an element that retains all of that element’s properties. Atoms are made up of a nucleus, containing protons and neutrons, and electrons that orbit the nucleus. Every element is made up of atoms with this basic structure, and each element’s atoms are unique to that element.
• Energy Sources...Throughout the centuries, humanity has learned to control energy, transforming it into forms that help sustain and improve our lifestyles. We burn energy stored within nonrenewable resources such as oil, coal, gas, to power our cars, generate electricity, and heat our homes. We use renewable resources such as wind, waterways, waves, and steam from under the Earth's crust to light our streets, grind our flour, and raise our buildings. We have even learned how to unleash the energy within the atom and control it to generate electricity. As our current stores of fossil fuels begin to run out, we will continue to look for new ways to locate sources of stored energy, new methods of capturing the energy within the motion of our air and waters, and perhaps ways to intercept more of the Sun's radiation in space.
Energy on the Move
• Waves...Waves are present everywhere in nature. They occur in fluids such as water, air, and solids, from the tiniest molecules to the whole Earth. Waves may be visible or invisible, depending on the medium. There is actually more to a wave than just a simple vibration or disturbance of particles. Waves are how energy moves from one place to another. When we study waves, we are primarily studying this transfer of energy. Waves are more than just a concept in science class. Waves are present in many facets of life that we enjoy, such as wakeboarding, talking on a telephone, or simply enjoying the view at the beach.
• Sounds...Have you ever felt your heart thump when someone is playing loud music with lots of bass? Have you ever held your hands over your ears when nails scratch on a chalkboard? Have you ever jumped when lightning and thunder strike? Sound energy is all around us. It can travel through any material, even our own bodies. Sounds are simply energy carried on longitudinal waves. The waves travel in a variety of ways, providing for all ranges and levels of sounds. Recording sounds with an oscilloscope gives a visual image that you can see. The graphs provide in-depth insight to the mechanical nature of sounds. Sounds are useful for everything from daily communication, to vital survival tactics. Without sound, a major slice of life as we know it would be missing. Sounds can be pleasant or they can be painful, depending on the source.
• Electromagnetic Waves...Imagine you are sitting on the beach, soaking up the sun. You have your radio along with you, and listen to your favorite tunes as you admire the beautiful scenery. You chat on your cell phone and notice you are sweating from the heat. Believe it or not, you've been bombarded with multiple electromagnetic waves. These waves are only a few of the many which radiate around us everyday. Starting with the shortest frequencies, gamma rays are extensively high-energy light waves that could potentially be harmful. At the other end of the spectrum, radio waves meander harmlessly through the atmosphere around us.
• Light...You have probably heard the phrase, “at the speed of light” at to describe a very fast event or movement. Light travels much faster than anything else in the universe, about 186,282.397 miles per second. Light has no mass, but is merely a stream of energy packets, or particles. Light does not need any sort of medium for waves to transport the energy. The visible light spectrum, which represents the colors we can see, is just a tiny slice of the larger electromagnetic spectrum.
• Mirrors and Lenses...Glass mirrors date from the third century A.D., in the Roman Empire. Over the centuries, glassworkers improved the production of mirrors to what we have today. Most bathrooms have mirrors, and decorators hang mirrors on the walls to lighten a room. We can now use mirrors in high technology, such as in telescopes and microscopes. About 25% of all children need to wear corrective lenses.
The Nature of Matter
• Solids, Liquids, and Gases...If you have ever seen lava coming out of a volcano, you know that it is molten rock that emerges at over 1000 °F. That is right – rock that is a liquid. Liquid nitrogen, on the other hand, is intensely cold and can freeze just about anything. A common chemistry demonstration is to freeze a rose or a banana and then hit it with a hammer, causing it to shatter. As nitrogen is usually a gas in nature, you may wonder how it can exist as a liquid. Temperature definitely explains these phenomena in part, but the story cannot be that simple when it comes to atoms. At the molecular level, lava is different than solid rock and liquid nitrogen is significantly different than its gaseous form. How they are different is the task at hand.
• Classification of Matter...Wherever we go, we are surrounded by different kinds of matter. We use matter as a general term, to describe anything with mass that takes up space in the universe. Different types of matter have different properties, yet all matter has some basic building blocks in common. The first ideas about matter came from the ancient Greeks. Today, scientists conduct experiments with the smallest possible building blocks of matter. How matter behaves depends on its condition, or state. Different states are organized differently. You will have the opportunity to see how matter is changed when it is exposed to different temperatures. Matter can also experience changes when different kinds combine with each other to form new products. Knowing about how matter behaves is useful in studying nature, on Earth and in space.
• Properties of Atoms and the Periodic Table...If you cut a sheet of paper in half, you get two half-sheets of paper. Each half still has the properties of paper; the only thing that changed is size. If you cut the halves in half, you get quarter sheets of paper. These quarters have the same properties as the original as well. How many times could you do this, so that the pieces retain their original properties? Atoms are the basic building blocks of all matter. There are many kinds of atoms, and they combine to form all the matter we see around us. They have properties that are so systematic, they can be organized into one easy reference: the periodic table.
• Chemical Bonds...You have learned that all the objects in the universe are made of matter, and that matter has mass and volume. The very smallest part of matter, that is still considered that kind of element, is an atom. Today we will see what happens when different atoms combine with each other. Atoms form different of chemical bonds, depending on what kind of atoms are present. We can predict what kind of bond will form if we have some details about the different atoms. We get these details from a reference chart called the Periodic Table. The Periodic Table features all of the known chemical elements, and gives important information about individual atoms of those elements, such as how many protons they have.
The Diversity of Matter
• Elements and Their Properties...Looking at the periodic table for the first time, students might suspect they will have to memorize all those symbols and little numbers. The world of matter is much more exciting than that! Each of the over one hundred elements has a unique set of properties. Collectively, the range of elements defines the properties of matter at the atomic level. Understanding the properties of each individual atom enables chemists to understand how different elements interact with one another. This explains how matter undergoes physical and chemical change. As you read through this lesson, you will learn about neutrons, nuclear decay, atomic number, electronegativity, and ionization energy.
• Organic Compounds...All living things, as far as we know, are united at the molecular level by their use of carbon for most of their chemistry. Many other elements are necessary for life, but the backbone of proteins, DNA, carbohydrates, and fats is predominantly carbon. Organic chemistry is the study of the structure and behavior of carbon-based molecules, the foundation for understanding the chemistry of life.
Interactions of Matter
• Solutions...We are surrounded by matter, but what do we really know about it? Try to name all the states of matter you have experienced. This lesson gives you the opportunity to explore matter in its various forms, such as what happens when different forms of matter interact. Do you get the same result when salt or sand is added to water? How does this impact our ability to separate the two after they are combined? These kinds of questions have great meaning to professionals like environmental scientists. When an environmental accident occurs, resulting in the spill of a chemical into our surface waters, an environmentalist must know how to separate the mixture that was produced by the accident.
• Chemical Reactions...Create a list of five chemicals in your home. Are the chemicals you identified pure substances or mixtures? You can identify a mixture as it contains a list of all the pure substances or chemicals it contains. The chemicals on your list have one important thing in common: they are all composed of atoms. All matter is composed of atoms. Atoms tend to form chemical bonds with other atoms. When atoms bond, pure substances composed of molecules form. Every pure substance has its own particular set of chemical and physical properties. Chemistry studies the interesting nature of atoms and the ways that they “rearrange.” When atoms rearrange, new pure substances form with new properties. Chemical engineers find ways to produce new chemicals or pure substances with properties that benefit humans.
• Acids, Bases, and Salts...Acids and bases are special classes of chemical compounds, which play an essential role in our society and our lives. These important substances are found in household products, the food we eat, and are used throughout the world. In this lesson, you will learn how these compounds behave when mixed together, how to recognize each type of compound, what the pH scale is, and how it applies to the study of acids and bases.
• Magnetism...A magnet is any item that produces a magnetic field. Therefore a magnet attracts metals such as iron, nickel, and cobalt. The strongest natural magnet is made of magnetite and has been called lodestone throughout history. This magnetite can be used to cause objects that contain iron to become magnetized. Magnets are used in navigation, in the medical field, and in the industrial realm. They are even fun to play with!
• Magnetism-C...A magnet is any item that produces a magnetic field. Therefore a magnet attracts metals such as iron, nickel, and cobalt. The strongest natural magnet is made of magnetite and has been called lodestone throughout history. This magnetite can be used to cause objects that contain iron to become magnetized. Magnets are used in navigation, in the medical field, and in the industrial realm. They are even fun to play with!