Science Study Guide PDF
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This document is a study guide on light, covering reflection, refraction, absorption, the human eye, sound waves and the environment. The guide contains a comprehensive explanation of the different concepts and phenomena.
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Science Study Guide :) Light: Reflection: It happens when the light rays bounce off smooth, shiny surfaces, making it so that you can see yourself. This happens because the light rays cannot pass through the opaque object, and it bounces off of the object, illuminating it, then at the shiny surface,...
Science Study Guide :) Light: Reflection: It happens when the light rays bounce off smooth, shiny surfaces, making it so that you can see yourself. This happens because the light rays cannot pass through the opaque object, and it bounces off of the object, illuminating it, then at the shiny surface, creating a reflection. There are different types of reflection, such as: Regular Reflection: It occurs when the light rays reflect off a smooth surface, creating a clear, sharp image. In a regular reflection, the angle of incidence (the angle at which light enters) is always the same as the angle of reflection. An Example of this is the reflection of a regular mirror. Diffuse Reflection: It occurs when the light rays reflect off of a rough surface, creating a distorted image. An Example of this is the surface of a lake on a windy day. Concave Reflection: The light rays reflect inward to one focal point, making the image smaller and inverting it, but sometimes making it upright. Convex Reflection: The light rays reflect outward from the object, magnifying, and bulging the image, but keeping it upright. Transmittance: It occurs when light travels through something clear or translucent, allowing someone to see to the other side. Refraction: A light ray bends whenever it travels at an angle into a medium of different refractive indices. This change in speed results in a change in direction. For example, a straw passing through water. Absorption: When all, or almost all, of the light rays are absorbed, or scattered by an opaque, rough object. The color of an object is seen because the object merely reflects, absorbs, and transmits one or more colors that make up light. Some examples of this are shoes. Eye: Parts of the Eye: Lens: The lens is a clear part of the eye behind the iris that helps to focus light, or an image, on the retina. Cornea: The cornea is the clear outer part of the eye’s focusing system located at the front of the eye. Iris: The iris is the colored part of the eye that regulates the amount of light entering the eye. The ciliary muscle: A muscle in the eye responsible for adjusting the shape of the lens to enable focusing on objects at different distances. Optic nerve: The optic nerve is the largest sensory nerve of the eye. It carries impulses for sight from the retina to the brain. Pupil: The pupil is the opening at the center of the iris. The iris adjusts the size of the pupil and controls the amount of light that can enter the eye. Retina: The retina is the light-sensitive tissue at the back of the eye. The retina converts light into electrical impulses that are sent to the brain through the optic nerve. Vitreous gel: The vitreous gel is a transparent, colorless mass that fills the rear two-thirds of the eyeball, between the lens and the retina. Vision Defects: Nearsighted: When a longer shaped eye focuses the light in front of the retina, meaning that they can’t see far away. Farsighted: When a shorter shaped eye focuses the light behind the retina, meaning they can’t see up close Astigmatism: When the cornea is irregularly shaped, meaning that the light is focused in different spots on the retina causing blurry vision. Sound Waves: What is the sound? Sound is a longitudinal wave that can only travel through matter. It is created by vibrations, which produce soundwaves by moving molecules in the air. Frequency: The amount of complete oscillation (cycles) of sound waves that occur in one second (measured in Hertz, Hz). Amplitude: A measurement of the amount of energy transferred by a wave. Amplitude on a transverse wave is typically measured as the distance between the peak or trough of the wave and the equilibrium position, or the position of the medium at rest (measured in decibels, dB). Period: The time taken for one complete oscillation (cycle) of a sound wave to pass a given point (measured in seconds). Compressions and Rarefactions: Compression is a region in a longitudinal wave where the particles are closest together (waves crest). A rarefaction is a region in a longitudinal wave where the particles are farthest apart (waves trough). Wavelength: The distance between two consecutive points on a wave (measured in metres) Speed of sound: How fast a wave can travel through a medium. Solid is the fastest, then liquids, then gases. Sound travels faster in hotter temperatures than colder ones. Formulas: The Environment: Greenhouse Gases: Greenhouse effect: The greenhouse effect is the process through which heat is trapped near Earth's surface by substances known as 'greenhouse gases.' Imagine these gases as a cozy blanket enveloping our planet, helping to maintain a warmer temperature than it would have otherwise. Renewable/Non- Renewable: Natural resources can be grouped into two groups: renewable and non-renewable. Renewable resources will naturally replenish themselves over time, like wind, solar, plants, trees, etc. Non-renewable will be gone forever once used or take too long to replenish in time for our use, like coal, fuel, etc. Pollution: