Midterm Study Guide - Physical Science
Waves: 6.P.1.1-6.P.1.3, Matter: 6.P.2.1-6.P.2.3, Heat: 6.P.3.1-6.P.3.3
6.P.1.1-All waves transmit energy and are created when a source creates a vibration. Compressional/longitudinal waves must travel through a medium while transverse waves are capable of traveling through a medium and space, which is also known as a vacuum. The vibrations cause waves that spread away from the source.Waves can differ based on how fast the wave travels or how long the distance is between the peaks (wavelengths).Sound, light, earthquakes, and echoes are all examples of waves that differ based on speed and the types of material they can travel through. Light waves (examples of transverse waves) are unique in their ability to travel through a vacuum. Sound waves (examples of compressional/ longitudinal waves) are a form of energy that results when vibrating materials produce waves that move through matter.Earthquakes are vibrations in the earth that release the potential energy stored in rocks. Earthquakes create seismic waves. Echoesare examples of sound waves.Identify the basic characteristics of a transverse wave: trough, crest, amplitude, and wavelength. Identify the basic characteristics of a longitudinal (compressional) wave: amplitude, rarefaction, and compression.
6.P.1.2 - Light travels in transverse waves. There are 7 main types of light waves (radiowaves, infrared, visible light, ultraviolet, x-rays, and gammarays), which are arranged in order from low frequency to high frequency on the electromagnetic spectrum.Light is a form of energy that comes from the Sun and from objects on Earth, like light bulbs.Light can be absorbed, reflected, refracted, or scattered depending on the properties of the object and the type and angle of light when it hits the object (you must know the differences between these terms).The structure of the human eye can detect many colors in visible light that are reflected by objects. Understand how the eye works, such as the parts of the eye, and the function of these structures. Know what can harm vision, as well as optical illusions, near sightedness, and far sightedness. We are able to see objects around us when light has been reflected off that object and enters the eye. Human eyes can only detect one type of light wave from the electromagnetic spectrum: visible light (ROY G BIV). Color is known as the different frequencies of light. Differences of frequencies within the visible light spectrum are show up as different colors in our eye (ROY G BIV).
6.P.1.3 - Know how the ear works, such as the structures within the ear, functions of those structures, and the conditions that affect hearing. Something can be "heard" when sound waves from it enter the ear. The ear receives sound waves as vibrations and changes them to signals that are interpreted by the brain. Sound waves have different characteristics such as frequency and amplitude, which will determine the properties of sound such as pitch, volume, and intensity.Understand how sound travels through different materials, such as solids, liquids, and gases.
6.P.2.1 - Recognize that there are more than 100 elements(organized on the periodic table) that combine inmany ways to make up all of the living and nonliving things in the universe. Recognize that matter is made of extremely small particles, too small to be seen with a classroom microscope, called atoms. Atoms have all of the properties of matter. Atoms are the smallest part of an element. Recognize that all atoms of the same element have the same properties; i.e. all iron atoms have the same mass and have the same volume. This means thatall iron has the same properties because the properties of every iron atom are the same. It also means that iron atoms are different from every other type of atom.
6.P.2.2 - A substance in a: Solid phase is mostlystiff, has a definite volume and shape. The atoms that make up a solid are packed close together and are not compressible. Because all solids have some thermal energy, atoms in a solid do vibrate. However, this movement is very small and very fast, and cannot be seenwithout special equipment. When heat is added a solid can become a liquid. Liquids have a specific volume, but are able to change their shape by flowing. Liquids are similar to solids in that the atoms touch. However the atoms are able to slide around each other. Since atoms in liquids canstill touch the densities of liquid will be very close to that of a solid (water is a special exception). Since the liquid molecules can slide around each other they will take the shape of their container. When heat is added a liquid can become a gas. Gases have no specific volume or shape. If not put in a container gases will spread out forever. If contained they will take the shape of their container. Each of the atoms is well separated causing in a very low density. Energy appears in different forms. Heat energy is in the disorderly motion of molecules. Atoms and molecules are forever in motion. Increased temperature means more moving so most substances expand when heated. Most substances can exist as a solid, liquid, or gas depending on thetemperature of the substance.
6.P.2.3 - A substance has characteristic properties such as density, a boiling point, melting point and solubility, all of which stay the same no matter how much of the substanceyou have. Because of this these properties can be used to identify substances. Physical properties involve things that can be measured without changing the identity of the substance. Matter can undergo physical changes, which affect only physical properties. Physical changes can involve changes in energy. Solubility means the amount of a substance that can be dissolved in a specific amount of liquid. A solute’sability to dissolve in a substance depends on the chemical properties of the liquid. Another important factor that influences solubility is the temperature of the substances (both the solute and the solvent). A solvent is a liquid that something can be dissolved in. The most common solvent is water.Density is a property that describes the connection between mass and volume. Recognize that each substance changes its state of matterat different temperatures. Recognize that melting and freezing of a pure substance takes place at the same temperature and the boiling temperature is the same as the condensing temperature. The temperature remains constant during state of matter changes in pure substances.
6.P.3.1 - Energy can be transferred in different ways: thermally(when a warmer object is in contact with a cooler),mechanically(when two objects push or pull on each other over a distance),electrically (when an electrical source such as a battery or generator is connected in a complete circuit to an electrical device), and by electromagnetic waves. Thermal energy is moved through a material when the atoms that make up the material run into each other. Heat flows through materials or across space from warm objects to cooler objects, until both objects are at equilibrium. Heat travels through solids, mainly by conduction. Heat is spread in fluids(both liquids and gases), through convection. Radiation is energy that travels across distances in the form of electromagnetic waves. Over time, thermal energy spreads throughout a material and from one material to another if they are touching (conduction). Thermal energy can also be moved by currents in air, water,and other fluids (convection).
6.P.3.2–Visible light and other electromagnetic waves can warm objects. How much anwarms updepends on the intensity of the light, how long it shines on the object, and how much of the light is absorbed by the object. When light interacts with matter it is absorbed, transmitted, refracted, and/or reflected (scattered). An example of scattering is when the sky is blue. The sun is a major source of energy for changes on the earth’s surface. The sun loses energy by emitting light. A tiny fraction of the light reaches the earth, transferring energy from the sun to the earth. The sun’s energy arrives as a range of wavelengths, including theVisible spectrum(the portion of the electromagnetic spectrum that is human can see). Electromagnetic radiation in this range of wavelengths is called visible light or simply light. Infrared light has a longer wavelength than visible light and is detected most often by its heating effect. Infrared imaging has uses in space exploration and with satellite imaging. Ultraviolet light has shorter wavelengths than visible light. These wavelengths are responsible for causing sunburns. Most of these waves are blocked from entering Earth’s atmosphere by Earth’satmospherebut some days, more ultraviolet waves get through our atmosphere. Scientists have developed a UV index to help people protect themselves from these harmful ultraviolet waves. UV light is the types of waves used in tanning beds.
6.P.3.3- Thermal energy is transferred through a material when atoms in the material run into each other. Over time, thermal energy spreads out through a material (and from one material to another) if they are in contact (conduction). Thermal energy can also be transferred by means of currents in air, water, or other fluids (convection). In addition, some thermal energy is changed into light energy and radiated into the environment by electromagnetic waves; that light energy can be changed back into thermal energy when the electromagnetic waves strike another material. A material tends to cool down unless some other form of energy is changed to thermal energy in the material. We need some things to conduct heat easily. Some materials that conduct heat easily are aluminum, steel, and copper. We call these materials thermal conductors. Similarly, there are things that we do not want to conduct heat (pot handles, spatula, cooking utensils) and these items are normally made of materials that slow down heat transfer. We call such materials thermal insulators. For example, expansion joint strips in bridges allow for the bridge to expand in hot weather and not break. These same joint strips allow for the bridge to contract in cold weather and not break.Electrical energy also passes through conductors. An electrical conductor is a material that an electrical current can flow easily though. An electrical insulator is a material through which electrical current does not easily flow. Electrical conductors include most metals, while most nonmetallic solids (rubber, glass, porcelain, ceramic) are electrical insulators.