th 4 Grade Science Which word means a conclusion based on evidence about events that have already occurred? inference Which word means a forecast about what may happen in some future situation? Scientific prediction Which word means a fair test driven by a hypothesis? Experiment What word means something that is deliberately changed in an experiment? Independent variable Which word describes variables that will change as a result of doing an experiment? Dependent variable Which word means an educated guess about what will happen in an experiment? Hypothesis Which word means something that is not allowed to change in an experiment? Constant This defines what is to be investigated in an experiment and is often written as a question. Purpose What are the step by step directions to follow in order to conduct an experiment? Procedure What is the list of items used in an experiment called? Materials What is the summary that supports or contradicts a hypothesis? Conclusion What is a graph, chart, or table used to display results called? Data What is called when you read, get advice, or make observations about a project? Research Which word means the ability to do work? Energy Which word means the result of a force moving an object through a distance? Work Which type of energy is moving energy? Kinetic energy Which type of energy is stored in an object? Potential energy What are three common forms of energy? Electrical, mechanical, chemical Which word means any combination of two or more simple machines? Compound machines Which machines are made of many compound machines? Complex machines How do machines make work easier and more efficient? By changing the direction of or increasing the effect of a force Which word describes the relationship of energy expended to work accomplished? efficiency Which word means the resistance to motion created by two objects moving against each other? Friction What does friction create? Heat Unless acted on by a force, objects in motion ______ and objects at rest _______. Stay in motion; stay at rest. What are negative charges called? Electrons What does a continuous flow of electrons create? Electric current What is the path taken by an electric current called? Circuit Which circuits allow the movement of electrical energy? Closed circuits Which circuits prevent the movement of electrical energy? Open circuits What are two units of measure used to describe electricity? Hertz and amps What type of voltage do common dry cell batteries generally have? Low voltage Which word describes materials that electrical energy moves through? Conductors What materials do not conduct electricity well? Insulators In which circuit is there only one pathway for the current? Series circuit In which circuit is there two or more pathways for the current? Parallel circuit Which word means the discharge of static electricity in the atmosphere? Lightning Which part of the plant anchors it and takes water and nutrients from the soil? Roots Which part of the plant provides support and allows movement of water nutrients? Stem What are the two general groups that the plant kingdom can be divided into? Those that reproduce with seeds and those that reproduce with spores What are the reproductive parts of the flower? Stamen and pistil What are the small leaves that form the housing of the developing flower? Sepals What is the process by which pollen is transferred from the stamen to the pistil called? Pollination What are two plants that reproduce with spores? Ferns and mosses What is the process in which green plants produce their own food called? Photosynthesis What do green plants use along with carbon dioxide, water, nutrients, and sunlight to produce food? Chlorophyll What is the primary food producing part of green plants? Leaves What word describes a period of suspended life processes brought on by changes in the environment? Dormancy What are the physical attributes that help organisms meet a life need called? Structural adaptations What are the types of activities organisms perform to meet a life need called? Behavioral adaptations Which word describes all of the populations that live together in the same place? Community What is the organization of communities based on in a given ecosystem? Utilization of energy Which word describes green plants which make their own food from sunlight, air, and water? Producers What are animals referred to as because they eat food? Consumers Where is the greatest amount of energy in a community found? Producers What are organisms called that break down decayed plants and animals into smaller pieces that can be used again by living things? Decomposers Which word means the function that an organism performs in the food web of the community? Niche Who can have a major impact on the ecosystem? Humans Which word means the measure of the amount of heat energy in the atmosphere? Temperature What is the amount of moisture in the atmosphere called? Humidity What is air pressure due to? Weight of the air What can determine air pressure? Temperature of air What is the boundary between air masses of different temperature and humidity called? Front Which type of clouds are tall and vertical and are often called thunderheads? Cumulonimbus Which type of clouds are white and fluffy and are seen on nice days? Cumulus Which type of clouds are low hanging in layers that look like a gray haze in the sky? They can become fog. Stratus Which clouds are dark and normally seen when rain or snow is happening all day long? Nimbostratus What is a scientist that studies the weather called? Meteorologist Which tool is used to measure air pressure? Barometer Which tool is used to measure moisture in the air? Hygrometer Which tool measures wind speed? Anemometer Which tool measures precipitation? Rain gauge Which tool measures air temperature? Thermometer Which word means the travel within an orbit? Revolution How often does the Earth make one revolution around the sun? Once every 365 days How often does the moon revolve around the Earth? Once every 28 days When does a lunar eclipse occur? When moon moves into Earth’s shadow When does a solar eclipse occur? When moon moves between sun and Earth What causes seasons? Axial tilt of the Earth during revolution around the sun What causes phases of the moon to occur? Moon’s position in relation to Earth and sun What are the phases of the moon? New, crescent, quarter, gibbous, full The sun is an averaged-sized star. How many times bigger is its diameter than the Earth’s? 110 How many planets are in our solar system? 9 What number planet is the Earth from the sun? 3 What makes Earth different from other planets? Large amounts of water and oxygen Which two scientists believed the Earth was the center of the solar system? Aristotle and Ptolemy Which two scientists believed that the sun is in the center of our solar system which is what we believe today? Galileo and Copernicus Which space craft’s missions added a great deal to our understanding of the moon? NASA Apollo What are some of Virginia’s natural resources? Forests, arable land, coal, sand, wildlife, clean water and air Which word means an area over which surface water and materials it carries flows to a single collection place? Watershed Which watershed covers about half of Virginia’s land area? Chesapeake Bay watershed What watershed is land drained by rivers west of Roanoke part of? Mississippi watershed What are some of Virginia’s water resources? Groundwater, rivers, bays, lakes, reservoirs, Atlantic Ocean What are three things Virginia’s soil and land support? Space for economic activities, great variety of life, variety of recreational opportunities