Science Curriculum Framework
Standard One
Nature and Application of Science and Technology
The practice of science and the development of technology are critical pursuits of our society. These pursuits have involved diverse people throughout history and have led to continuous improvement in the quality of life and in our understanding of nature. Students will study the processes of scientific inquiry and technology development and the history and context within which these have been carried out.
Science as Inquiry
By the end of the eighth grade students should know that:
1. The design of an investigation, in many cases, is determined by the type of questions asked. Therefore, the thoughtful and informed structuring of such questions is an important part of scientific inquiry. For example, a question such as, “What are the similarities and differences among the plants that grow in this region?” requires a taxonomic investigation in which plants are collected, identified, and classified. On the other hand, answering – “What was the reaction of Marie Curie’s contemporaries to her work and accomplishments?” – may involve consulting, reviewing, and discussing both contemporary and historical publications as part of an investigative design. However, an experimental investigation in which systematic observations are made and where data are used and analyzed to construct an explanation could result from a question such as, “How do the physical properties of local soil samples lead to differences in drainage or percolation?”
Expand the learning event highlighted in A-1 grades 4-5. Ask reasonable, relevant, and testable scientific questions about topics of interest and determine the type and complexity of the investigation required to answer them.
2. The ultimate goal of any scientific investigation is to obtain evidence precise and thorough enough to answer a question. Various experimental designs and strategies can be developed to answer the same question. The comprehensiveness and sophistication of the investigation depend on the tools and technologies used.
Conduct a series of investigations with sufficient complexity to require the use of various experimental techniques and strategies; the separation and control of variables; the consolidation, organization and display of data; the development of conclusions; and the posing of additional questions. Develop oral and written presentations of the investigation to allow peer review of the results.
Develop the competence to use a variety of tools and techniques in order to solve a wide range of practical problems. Examples follow:
- Use calculators to compare amounts proportionally (e.g., proportion of fat, protein, carbohydrates in foods).
- Use computers to store and retrieve information in topical, alphabetical, numerical, and key word files and to create and manipulate individual files.
- Read analog and digital meters in instruments used to make direct measurements of length, volume, weight, elapsed time, and temperature and choose appropriate units for reporting magnitudes.
- Use cameras and tape recorders for capturing information.
3. Explanations in science result from careful and logical analysis of evidence gained from an investigation. Explanations relate causes to effects and develop relationships based on the evidence. Critical analysis of data is necessary to judge the quality and validity of the proposed explanation. Critical analysis skills learned in the classroom can be applied to judge the validity of claims made in everyday life.
As part of an investigation, use a variety of strategies to construct and develop logical explanations including:
- Deciding what evidence from an investigation is useful.
- Organizing and summarizing information and data in tables and graphs in order to identify relationships.
- Incorporating pie charts, bar and line graphs, two way data tables, diagrams, and symbols into written and oral presentations.
- Forming a logical argument about the cause and effect relationships in an investigation.
- Retrieving pertinent information from reference books, newspapers, magazines, compact discs, and computer data bases.
- Constructing models in order to visualize and explain the relationship among various elements of a product, process, or system.
Review and critically analyze claims made in popular magazines such as PEOPLE, TIME, DISCOVER, and in newspapers, television news programs or specials, to determine the validity of the claims and conclusions.
Science, Technology and Society
1. Social, cultural, environmental, scientific and technological strengths, and economic factors influence which scientific and technological areas are pursued and invested in. At the same time, the scientific discoveries made and technologies developed directly influence society and its habits, organization, and cultural values.
Investigate the relationship of factors such as resource availability and cultural tradition on the kinds of science and technologies pursued. Examples could include:
- An analysis of transportation methods and expertise around the world. The emphasis on mass transportation in Europe and Japan vs. the super highway system in the U.S. The emergence of Great Britain as a sea power.
- The emergence of the United States as a world power in the polymer industry.
- The global war on cancer and other serious diseases.
2. The issues surrounding science, technology, and society are complex and involve many risk/benefit considerations. Even though new technology may provide a solution to an important problem, its impact on human health, the environment, and social dynamics needs to be analyzed.
Explore and discuss various problems which have faced society and the technologies developed to deal with such problems. Identify the products and processes developed to solve these problems and consider the benefits delivered and the risks created by these new technologies. Such areas could include the management and control of sewage, the preservation of food, the fighting of tooth decay, the development of various modes of transportation, and the heating or lighting of homes.
History and Context of Science
1. Over the course of human history, science has been practiced by different people in different cultures. Unfortunately, women and minorities have often been discouraged or denied the opportunity of participating in science because of education and employment prejudices or restrictions.
Research the life, work, and contributions of a contemporary or historical scientist. Compare the background, human qualities, and factors that influenced the work of the scientist as part of a discussion of contemporary and historical variations of people who practice science.
Explore the historical under representation of women and minorities in many fields of science and engineering, and the strategies that education, business, and government in Delaware are employing to increase their representation in the scientific work force of the future.
2. People engaged in doing science are found in many occupations and institutions such as hospitals, universities, classrooms, industry, and farms. The nature of scientific investigation often requires that teams of individuals with different abilities work together to solve a problem or to understand the natural world.
Participate in visits to local facilities where science is practiced or participate in a class discussion with community individuals, including women and minorities, who work in science related occupations. Report and discuss the variety of opportunities for practicing science.
Investigate research projects which have been or are presently conducted in the State of Delaware (e.g., agriculture, material, medical, marine). Explore how individuals with different abilities contribute to the success of these projects.
Standard Two
Materials and Their Properties
Materials exist throughout our physical world. Students will develop a basic understanding of the structure and properties of materials. They will also experience and learn the processes by which materials are changed and how the uses of materials are related to their properties.
Grades 6-8
Properties and Structure of Matter
1. Elements are substances that cannot be decomposed into simple materials by chemical reaction. However, elements can react with other elements or materials to form compounds. There are more than 100 known elements which combine in a multitude of ways to produce compounds, which account for all living and nonliving substances.
Keep a journal over an extended period of time in order to identify and describe everyday and laboratory events that involve chemical reactions (e.g., silver tarnishing, metal corroding, mixing lime water and carbon dioxide) and result in formation of a new compound. Discuss how the properties of these new compounds differ from the properties of the original elements.
2. The three states or phases of matter (solid, liquid, gas) are determined by the arrangement, motion, and interaction of molecules. In the solid state, molecules are packed tightly together and their movement is restricted to vibrations. In the liquid state, molecules are more loosely packed and can slide past each other. In the gaseous state, molecules are less restricted and move freely. Changes in state require the addition or removal of heat but result in no change in the chemical structure of the material. Changes in either the temperature, pressure, or volume of a gas result in predictable changes in the other properties.
Design simple tests to investigate the various factors that affect the melting rate of ice cubes. Record the results and identify factors that contribute to differences in melting rate. Use simple models to explain the molecular changes that occur as the ice melts.
3. Some physical properties such as mass and volume depend upon the amount of material; others such as density and melting point, known as characteristic properties, are independent of the quantity and are unique to the material.
Conduct experiments to differentiate between physical properties that are characteristic of a material and those that depend upon the amount of material present (e.g., measure and graphically display the mass/volume ratio for a variety of different materials).
Mixtures and Solutions
1. Mixtures have component parts. Most natural materials such as milk, blood, mineral ores, sea water, soil and air; and man-made materials, such as processed foods, cosmetics, and paints are physical mixtures consisting of a variety of components in a wide range of concentrations. The individual components can be analyzed and separated by making use of their unique chemical and physical properties.
Identify common materials found in the classroom or at home which are mixtures. Determine the component parts of these mixtures by reading the labels, using paper chromatography, or through discussion with experts (e.g., scientist, parent, masonry worker). Describe how these mixtures were prepared and speculate as to whether they can be separated.
Investigate and discuss why the measurements of specific components of a physical mixture are reported to people (e.g., particles in the air, cholesterol in blood, unsaturated fats in foods, turbidity in lakes) and how these measurements are used to monitor health problems and/or environmental pollutants.
2. Solutions are homogenous mixtures of two or more components. The properties of a solution depend on the nature and concentration of the solute(s) (the material being dissolved) and the nature of the solvent(s) (the medium in which the solutes are dissolved).
Identify the component parts of a solution, and demonstrate the use of ratios and percentages in preparing solutions of different concentrations. Investigate and describe the properties of these solutions.
Transformation and Conservation of Matter
1. Substances react chemically in characteristic ways with other substances to form new substances. In all chemical reactions the total mass is conserved. Substances can be categorized and grouped based on similarity in reactivity, for example metals. (National Science Education Standards, November 1994.)
Identify and describe, by conducting laboratory activities or observing everyday events (e.g., rusting, cooking), how the properties of new substances formed during chemical change differ from the properties of the original material. Report the observations that indicate chemical change (e.g., changes in color, formation of precipitates or gases, or emission of light or heat).
Material Technology
1. Societies use the understanding of physical and chemical change to create new and useful products. The production of these materials has social, environmental, and other implications that require analyses of the risks and benefits.
Investigate an example of the influence of material technology on society (e.g., Bronze Age, Iron Age, synthetic fibers, solar cells). Examine the relationship between a civilization’s values, needs, and resources, and the kinds of technologies developed and accepted by society.
Standard Three
Energy and Its Effects
The flow of energy drives processes of change in all biological, chemical, and geological systems. A variety of sources can be transformed into energy forms which influence many facets of our daily lives. Students will study, discuss, and learn the factors that govern the flow of energy throughout the universe, the transformation of natural resources into useful energy forms, and the conservation of energy during interaction with materials.
Grades 6-8
Forms/Sources of Energy
1. The electromagnetic spectrum is composed of different wavelength domains. The radiation in this spectrum comes from various sources and spans energy levels from radio waves (longest wavelengths, lowest energy) through microwaves, infrared, visible, ultraviolet, x-rays, to gamma rays (shortest wavelengths, highest energy). White light from the Sun consists of a mixture of wavelengths and energies in the visible part of the electromagnetic spectrum (red to violet).
Demonstrate the existence of the colored components of white light by using a prism or diffraction grating. Explain the colors and their order in terms of energies and wavelengths.
Identify uses of non-visible forms of electromagnetic radiation such as microwaves, UV, and x-rays. Discuss the relationship between the energy of each form of radiation as well as its application and potential hazards.
2. Electrical energy results from the movement of electric charges (electrons) driven by a voltage through a complete circuit. Electrical energy can be readily generated, transmitted over great distances, and transformed into heat, light, sound, and motion. Electrical systems can be designed to perform a variety of tasks, using series, parallel, or combination circuits.
Design and assemble simple series and parallel circuits. Cite the advantages and applications of each.
Research and compare various sources of energy (e.g., waterpower, fossil fuel, nuclear) for the generation of electric power. Discuss the advantages and disadvantages of each.
3. Static electricity represents potential energy stored in a collection of separated negative and positive charges. Similar charges repel each other; opposite charges attract each other and can lead to a sudden flow of electrons (e.g., a spark, a lightning bolt).
Generate static electricity from various sources (e.g., by rubbing a plastic tube with a cloth) and investigate conditions that promote its production. Discuss the applications and hazards of static electricity.
4. Chemical energy is stored in elements and compounds. In most chemical reactions, energy is released or added to the system in the form of heat, light, electrical, or mechanical energy. (National Science Education Standards, 1994)
Measure the energy content of typical organic materials (e.g., wax, peanut, polyethylene). Discuss the importance of chemical energy as an energy source to meet societal needs in transportation, heating, lighting, batteries, and food.
Measure the changes in temperature resulting from chemical reactions which release or absorb heat (e.g., “HOT PACK” and a “COLD PACK”). Discuss the results in terms of the chemical and energy changes involved.
Force and Motion
1. Force must be used to change speed or direction (or both) of a moving object. In the absence of such a force, the object will continue to move with the same speed and in the same direction. Forces have directions and magnitudes that can be measured. Any change in motion depends upon the amount of force causing the change and the mass of the object.
Measure and compare the magnitude and direction of forces used in common activities such as lifting objects, stretching springs or rubber bands, and arm wrestling.
Give examples which show how the relationships among force, mass, and acceleration are important in common situations (e.g., hammering a nail, comparing rates at which a car and a heavily loaded truck can pull away from a stop sign).
2. Mechanical energy comes from the motion and/or the position of physical objects. The work done on an object depends on the applied force and on the distance that the object moves.
Observe and describe changes in kinetic and potential energy in common activities such as bouncing a ball or swinging on a swing.
3. The motion of an object can be described as its change in position, direction, and speed relative to another object.
Determine the speeds of objects (e.g., students running, walking, riding a bike) using measurements of distance and time. Compare the results both numerically and graphically.
4. Simple machines (e.g., levers, inclines, pulleys, gears) are used to change the force on an object and its speed or direction in order to make work easier.
Explain and demonstrate how common tools (e.g., pliers, crowbars, hammers, pulleys, can openers) incorporate simple machines in their designs. Discuss the forces and motions involved.
Use simple machine principles to design a device which performs a task (e.g., lift a weight, move a heavy object) that cannot be accomplished without the machine. Explain the forces and motions involved.
p>Transformation and Conservation of Energy
1. Almost all events in the Universe involve the transformation of one form of energy into another form with the release of heat. Regardless of the transformation, the total amount of energy remains constant.
Measure and qualitatively compare the heat changes involved in different kinds of energy transformations (e.g., temperature increases from different sizes of incandescent and fluorescent lights, temperature increases when different colored objects are exposed to the sun, temperature increases when a cup of metal balls is vigorously shaken or a nail hammered).
2. Heat energy is transported through materials by conduction, by convection in fluids (e.g., air or water), or across space by radiation. The addition or removal of heat from a material changes its temperature or its physical state (e.g., ice melting).
Use weather maps and reports over an extended period of time to show the effects of uneven heating and cooling of the earth’s surface on weather. Discuss the role of radiation, convection, and conduction in weather changes — see also Earth’s Dynamic Systems.
Interactions of Energy With Materials
1. Energy can travel as waves which are characterized by wavelength, frequency, amplitude, and speed. Waves have common properties of absorption, reflection, and refraction when they interact with matter. They are either mechanical (e.g., sound, earthquake, tidal) or electromagnetic (e.g., sunlight, radio waves); only electromagnetic waves will travel through a vacuum.
Generate waves (e.g., in water) and demonstrate common wave properties when the waves interact with surfaces and with each other.
2. The resistance to flow of an electric current through a material depends on the mobility of electrons in the material. In conductors (e.g. metals) the electrons flow easily, while in insulators (e.g., wood, glasses) they flow hardly at all. The resistance to flow converts electric energy to heat energy.
Compare the efficiency of different materials as electrical conductors and insulators.
Production/Consumption/Application of Energy
1. Technological advances throughout history (e.g., electric light, steam engine, internal combustion engine, radio, TV) have led to new applications which use different forms of energy. Such advances have led to increased demand for energy, and in some cases, unanticipated effects on society.
Work in groups to investigate and chart the impact of the development of the internal combustion engine (or other major change in technology) on life in America. Identify and report on the advantages and the unintended or unexpected consequences which resulted.
2. Energy is obtained from a variety of sources, some of which are finite and some of which are renewable. The major source of energy for society is chemical energy stored in fossil fuels created many years ago through the process of photosynthesis. Another source is nuclear energy. Renewable sources (e.g., wind, geothermal, waves, biomass) vary in their availability and ease of use.
List a variety of energy sources which provide alternatives to the use of fossil fuels, compare their relative ease of renewability, and explain their advantages and disadvantages. Discuss the various sources of energy used around the world and explain the basis for the differences.
3. Most energy used by industrial societies is derived from fossil fuel sources. Such sources are inherently limited on the earth and are unevenly distributed geographically. Responsible use of energy requires consideration of energy availability, efficiency, environmental issues, and alternative sources.
Use available information (e.g., from power companies) to conduct a personal audit of energy consumed by a family. Determine the amounts, types, and cost of energy (e.g., electricity, oil, gas, gasoline) used and the total energy use over a given period. Considering the efficiency of different applications, propose approaches to reduce energy use by a significant amount.
Standard Four
Earth in Space
The Earth system is part of the Solar System that exists within a vast Universe. The Earth’s motion and position relative to the Sun and the Moon are unique among planets of the Solar System which allows diverse forms of life to be supported on the Earth. Students will learn that even though the distributions and types of materials differ from planet to planet, the chemical composition of materials is identical and the same laws of science apply across the universe.
Grades 6-8
Solar System Models
1. The Universe is composed of billions of stars. The Sun is a medium size star which is many millions of miles closer to Earth than the next nearest star.
The following sample activity applies to this content statement.
2. The Solar System forms part of the Milky Way Galaxy, which is one of many galaxies that comprise the Universe. Some of the galaxies are so far away that their light takes billions of years to reach Earth.
Use scale drawings or triangulation to determine distance between specific points. Explain how these methods can be used to estimate astronomic distances.
Use a variety of visual aids to study the approximate location of the Solar System in the galaxy. Explain how the Solar System moves relative to the Milky Way Galaxy.
3. The nine planets, their respective Moon(s), comets and many asteroids, and meteorites orbit the Sun which is the gravitational center of the Solar System.
Construct scale models of the Solar System. Use the models to describe the relative sizes of the planets (as viewed from the Earth) and their distances from the Sun.
Use a variety of resources (e.g., NASA photographs, computer simulations, satellite images) to compare the physical properties (e.g., size, surface features, tilt of axis) of the planets as well as their similarities and differences.
4. The apparent shape of the Moon changes dramatically as it moves in its orbit. These shapes, called phases, relate to lunar visibility and the times at which the Moon rises and sets. The Moon produces no light of its own and shines only as a result of sunlight reflected from its surface.
Monitor the position and phases of the Moon for a complete cycle, and construct a Sun/Moon/Earth model to explain the observations. Use the model to explain the occurrence of eclipses.
5. The yearly revolution of Earth in its orbit about the Sun and the tilt of Earth on its axis (23.5 degrees) cause the angle at which sunlight strikes the Earth to vary at different locations. This causes differences in the heating of Earth’s surface which produce seasonal variations in weather and a variety of climates.
Use the Earth/Sun/Moon model to demonstrate how seasonal changes relate to the tilt of the Earth in relationship to the Earth’s orbit around the Sun and to predict the season in different hemispheres of the Earth at any given time.
Interactions in the Solar System
1. Nuclear processes that take place in the Sun continuously convert matter to energy. A small portion of this energy which is intercepted by Earth drives biological, chemical, and physical processes on Earth.
Design experiments to demonstrate that light from a source such as the Sun has color and brightness and directions of travel. Explain the colors and their order in terms of energies and wavelength - See also Energy and Its Effects.
2. The gravitational attraction that exists between all forms of matter holds objects on Earth, causes tides, keeps the Solar System and galaxy together, and controls the movement of the planets in the Solar System.
Compare a person’s weight and mass on the Earth, on the Moon, and in an orbiting satellite and explain the similarities and differences. Discuss the importance of these effects to the work of astronauts (e.g., drinking water, walking, lifting a weight).
Explain qualitatively the effect of the gravitational pull of the Earth and the Moon on the motion (distance traveled, speed) of a rocket moving from Earth to the Moon - See also Energy and Its Effects.
Technology and Applications
1. Close-up pictures and data received from space probes allow scientists to compare the physical properties of planets (e.g., size, surface features, number of rings) and to speculate about conditions on other planets.
Select a space probe mission (e.g., Mariner 4, Voyager, Galileo) and research what type of valuable information these robotic explorers have provided scientists about the Solar System. Discuss how information received from space probes has either confirmed or modified scientific theories concerning conditions on other planets.
Standard Five
Earth’s Dynamic Systems
Earth’s features provide a record of how Earth has changed over time. This dynamic history can be documented and explained by a variety of physical, chemical, biological, and geological processes. Students will study and learn to identify components of the various Earth systems and understand the changes and patterns that result from interactions within and between these systems.
Grades 6-8
Components of Earth
1. Rocks and minerals are classified according to their chemical
and physical properties. Rocks also are classified according to how they are formed.
Sort and group rocks and minerals into natural classification systems using physical
and chemical tests. 2. Sedimentary rocks, which are made of particles from other rocks and organic remains,
are laid down in horizontal layers. Fossilized remains and successive layering of
sedimentary rocks provide evidence of the Earth’s history. Absolute age is determined
by radioactive dating.
Construct models and geological profiles to demonstrate the age relationship of
sedimentary rock layers. 3. The atmosphere has properties that can be observed, measured, and used to predict
changes in weather and to identify climatic patterns.
Perform daily weather measurements over an extended period of time using a variety of
instruments (e.g., barometer, anemometer, sling psychrometer). Compare and contrast the
measurements to local and regional weather data. 4. Water falling to Earth flows over the surface as run-off and collects in ocean
basins, rivers, lakes, ice caps, and underground. Water stored underground (sub-surface)
and water stored above ground (surface) form a continuum, each supplying water to the
other. Human activity and natural events can introduce chemicals affecting the quality of
the water supply.
Identify water sources for the Delaware Estuary and the impact of human activities upon
it. Determine the compositions and suitability for use of various local water sources
(e.g., rivers, streams, wells); investigate reasons for differences in the results and
determine how regulations affect water use.
Interactions Among Earth’s Systems
1. Volcanoes, earthquakes, and other mountain-building processes are responsible for most major features of the Earth’s crust.
Plot the location of earthquakes, volcanoes, trenches, and oceanic ridges to account for patterns of activity associated with tectonic plates .
2. Rocks are changed by erosion and deposition and by exposure to heat and pressure. There are a variety of physical and chemical processes that lead to the decomposition and breakdown of rocks and the eventual formation of soils and sediments. These soils and sediments can then be transported to other places by wind, flowing water, waves, and ice.
Design and build models to demonstrate how wind and water shape the land. Explain how erosional agents such as water and ice produce distinctive landforms (e.g., water and bad lands, ice and glacial valleys, waves and sea cliffs). (National Geography Standards, 1994)
Design tests to study the effects of physical processes (freezing and thawing of water, erosion) and chemical processes (oxidation, acidification) on the structure of rocks, and speculate on the impact of climate, topography, and airborne and water pollutants on these processes.
Investigate factors influencing erosion and deposition and relate the results to local areas of erosion. Apply this information to economic decisions concerning the use of land for construction, farming, industry, and recreation.
3. The cycling of water in the atmosphere is driven by energy transfer processes, such as convection and radiation, and is constantly changing the location and phase of water.
Design simple experiments to demonstrate the influence of wind and temperature on the hydrologic cycle.
4. Uneven heating and cooling of Earth’s surface produce various air masses which differ in density, humidity, and temperature. The origin, movement, and interaction of these air masses result in significant weather changes.
Use U. S. weather maps to identify and describe air masses, fronts, and their movement.
Perform daily weather measurements over an extended period of time using a variety of instruments (e.g., barometer, anemometer, sling psychrometer). Compare and contrast the measurements to local and regional weather data.
Discuss the origin and impact of the great storms of the east coast (e.g., hurricanes, "nor’easters", snow and ice storms). Assess adequacy of emergency planning procedures to respond to the damage which such storms can cause.
5. Ocean currents affect the weather and long term climatic patterns of a region. Large bodies of water (oceans, the Great Lakes, inland seas) can also affect the weather and climate of an area.
Investigate the influence of the Atlantic Ocean on erosion of coastal areas, commerce, and the climate of Delaware.
Examine maps of ocean currents and trace the origin and flow of such currents to explain the transport of heat energy. Speculate which currents have dominate influence on the Delaware coast.
Technology and Applications
1. Instrumentation (e.g., pH meters, water analysis kits) and computer models enable the measure and analysis of environmental pollution. Sources of environmental pollution can be tracked using maps and satellite imagery.
Use technology (e.g., maps, satellite imagery, instrumentation) to locate possible sources of environmental pollution. Compare sources with meteorological data to locate the probable origin of regional contamination.
Standard Six
Life Processes
The natural world is defined by organisms and life processes which conform to the principles regarding conservation and transformation of matter and energy. Students will learn how living organisms use matter and energy to build their structures and conduct their life processes. They will learn the mechanisms and behaviors used by living organisms to regulate their internal environments and to respond to changes in their surroundings. Students will also study how knowledge about life processes can be applied to improving human health and well being.
Grades 6-8
Structure/Function Relationship
1. The basic unit of all living organisms is the cell. In multi-cellular organisms, different cells are specialized to perform various tasks, and cells similar in shape and function are organized into groups (e.g., muscle cells, motor nerve cells).
The following sample activity applies to this content statement.
2. Cells contain a set of observable structures called organelles (e.g., cell wall, cell membrane, nucleus, chloroplast, and vacuole) that control the various functions of the cell such as structural support, exchange of materials, photosynthesis, and storage of essential materials.
Use microscopes to observe a variety of prepared slides of plant and animal cells. Sketch the cells and label any observable organelles. Describe how specific groups of cells differ in structure from other groups of cells and explain how the distinctive structure of the cells determine their function.
3. Unicellular organisms perform, within a single cell, all of life’s specific functions such as water regulation, digestion, locomotion , and circulation using specialized structures for each function.
Collect water samples from a local pond that contains abundant microorganisms. Examine the water with hand lenses and microscopes and make sketches of some of the organisms observed, noting how they move and how they interact. Select a “favorite life form” and make a large painting of the organism. Determine the role of the favorite life form in the aquatic system and prepare a report on the information. Use the painting and the reports to create a class mural of the local pond and its aquatic environment. (Aquatic, Project Wild, 1987)
Matter and Energy Transformations
1. Plants make their food by the process of photosynthesis. Using light energy, green plants convert water and carbon dioxide into energy-rich simple sugars and oxygen. Sugar is the source of food used by most plants, and ultimately, by all other consumers. Oxygen produced during photosynthesis is required for the survival of most plants and animals.
Conduct simple experiments with green plants to determine the requirements and products of photosynthesis. For example, place elodea in a clean inverted funnel and place both the elodea and funnel in a beaker of water. Place a test tube over the spout end of the funnel and measure oxygen bubble production as evidence of photosynthesis.
Determine the amount of oxygen produced from an aquatic green plant such as elodea. Prepare two containers with equal amounts of water and green plants. Place one container in sunlight and the other in the dark for several hours. Test for dissolved oxygen produced by the plant using a LaMotte or Hach D. O. Kit.
2. All living things obtain energy from food. Energy is needed for living cells to carry out all the processes of life such as growing, disposing of wastes, making new cells, and using food.
Read a variety of articles which address the relationship of human energy requirements to diet. Develop tables which describe the content (e.g., fiber, fat, carbohydrates, protein) of the foods routinely consumed by the class. List the daily activities of the class and their energy requirements (rank order from highest to lowest) and describe the various diets which satisfy the energy required to support such activities.
Regulation and Behavior
1. All organisms obtain and use resources to grow, reproduce, and maintain a relatively stable environment while living in a constantly changing external environment. Regulation of an organism’s internal environment involves sensing external changes in the environment and changing physiological activities to keep within the range required to survive. (National Science Education Standards, 1994)
Conduct a simple investigation to determine factors that affect pulse rate. Work with a partner and record pulse rates while sitting quietly, lying on the floor, running in place, and doing jumping jacks. Construct a graph of your pulse rate over time and describe how the graph indicates that you might be observing a system in dynamic balance. (Investigating Systems and Change, BSCS, 1994)
Use cardboard scraps, boxes, and other classroom materials to design and build mazes to determine how bean plants or sprouted potatoes respond when a light source is not directly available. Based on the design of the maze, predict how the plants will look after two weeks. Measure the plants regularly and indicate how they grew on their journey to reach the light source. At the end of two weeks display the plant mazes and describe how the plants responded to their surrounding environment in meeting their basic needs for light. (Gro Lab, Activities for Growing Minds, The National Gardening Association, 1990)
2. Behavior is one kind of response an organism makes to environmental stimuli. Behavioral responses require coordination and communication at many levels including cells, organ systems, and whole organisms.
Health and Technology Applications
1. The functioning and health of organisms, including humans, are influenced by heredity, diet, lifestyle, bacteria, viruses, parasites, and the environment. Certain body structures and systems function to protect against disease and injury.
Select a relevant health topic (e.g., diet, drugs, exercise, disease), write a research-based paper that explains how normal life processes are affected by your selection, and give an oral presentation on the results of the research.
2. Sanitation measures such as the use of sewers, landfills, quarantines, and safe food handling are important in controlling the spread of organisms that cause disease.
Investigate the impact of improved sanitation measures on the health of the local population using a full range of community resources such as guest lecturers, field trips, libraries, and community agencies.
Standard Seven
Diversity and Continuity of Living Things
The natural world consists of a diversity of organisms that transmit their characteristics to future generations. Students will study how living things reproduce, develop, and transmit traits, and how theories of evolution explain the unity and diversity of species found on Earth. Students will also study how knowledge of genetics, reproduction, and development is being applied to improve agriculture and human health.
Grades 6-8
Heredity
1. Chromosomes, which are components of cells, occur in pairs and carry hereditary information. The subunits of chromosomes are genes which direct the formation of an organism's traits.
Use models to demonstrate that chromosomes and genes come in pairs and that chromosomes are composed of many genes. Use these same models to discuss how genetic material is transmitted from cell to cell or from parent to offspring.
Use Punnett squares and pedigree charts to demonstrate and predict how single gene traits, such as seed shape in peas and tongue rolling in humans, are transmitted to offspring.
Reproduction and Development
1. In asexual reproduction, a new organism grows from a single cell or a cluster of cells provided by the parent and results in offspring genetically identical to the parent.
Observe asexual reproduction in a variety of organisms (e.g., yeast, hydra, plants) and discuss important characteristics of this form of reproduction in preparation for an in-depth comparison with sexual reproduction.
2. In sexual reproduction, gametes (egg and sperm), which are produced in specialized structures of the parents, fuse during fertilization to form an organism. Since each gamete contributes a set of chromosomes, the offspring have traits of both parents.
Describe sexual reproductive patterns in flowering plants and a variety of animals. Discuss the difference between sexual and asexual reproduction.
3. After the egg is fertilized, it undergoes an orderly series of changes involving cell division and differentiation as a new organism is formed. Each of the new cells in the developing organism receives an exact copy of the genetic information contained in the fertilized egg.
Observe, describe, and measure changes that occur in an organism (e.g., bean plant, butterfly, frog, chicken) as it develops from a seed or fertilized egg into an adult.
Evolution
1. Natural selection is the process by which some individuals with certain traits are more likely to survive and produce greater numbers of offspring than other organisms of the same species. Conditions in the environment can affect which individuals survive in order to reproduce and pass their traits on to future generations. Small differences between parents and offspring accumulate over many generations and ultimately new species may arise.
Conduct a natural selection simulation to demonstrate that a specific trait has selective advantages for an organism. For example, study the advantages of protective coloration of a species that is preyed upon. Scatter different colored toothpicks in the grass, role play a predator, and quickly pick up as many toothpicks as possible. Collect data on the remaining colors and discuss the advantages of protective coloration in the survival of organisms.
Investigate and discuss how short term physiological adaptations of an organism (e.g., skin tanning, muscle development, formation of calluses) differ from long term evolutionary adaptations that occur in a group of organisms over generations.
2. Anatomical comparisons and fossils provide evidence for evolution and indicate that the first organisms originated on the Earth between three and four billion years ago. The Earth’s present day species evolved from earlier, distinctly different species.
Examine fossils and anatomical models for evidence of similarities and differences and draw reasonable conclusions about evolutionary change over time.
Diversity
1. Organisms are currently classified into five kingdoms (monera, protista, fungi, plantal, animalia) based on similarities in structure and behavior.
Examine a variety of common organisms representing the five kingdoms, and construct and use a dichotomous key to classify these organisms.
2. A species is an important biological grouping of organisms whose members have similar structures, normally interbreed, and produce fertile offspring.
Determine, using the definition of species, the number of species present in a sample containing many kinds of organisms.
3. Each structure in an organism is uniquely adapted to perform a particular function for enhancing the ability of the organism to survive. The great variety of body forms found in different species enable organisms to survive in diverse environments.
Examine selected internal and external structures of different plant and animal species. Describe and compare those structures that perform a common function, (e.g., teeth of herbivores/carnivores, leaves in deciduous trees/conifers, breathing organs in aquatic animals/terrestrial animals) and explain how differences in each structure enables the organism to survive in its particular environment.
Health and Technology Applications
1. Selective breeding is used to produce new varieties of cultivated plants and domesticated animals with enhanced traits.
Use a variety of resources to develop a report on selective breeding. Select a cultivated plant (e.g., “Super Sweet Corn”, “Sugar Baby Watermelon”) or domesticated animal (e.g., “Ovenstuffer Roaster”, Low Fat Hogs) and trace its history of development and the traits of the plant or animal that were enhanced by selective breeding.
2. Knowledge gained from research in genetics is being applied to areas of human health.
Select one area of genetic, reproductive, or embryonic research. Explain the human benefits as well as the economic, social, and ethical issues raised by such research.
Standard Eight
Ecology
Organisms are linked to one another in an ecosystem by the flow of energy and the cycling of materials. Humans are an integral part of the natural system and human activities can alter the stability of ecosystems. Students will acquire a basic understanding of the structure of ecosystems and how they function and change. They will also study how humans can apply scientific and technological knowledge about ecosystems in making informed decisions about the use of natural resources.
1. An ecosystem consists of all the organisms that live together and interact with each other and their physical environment.
Investigate and describe multiple ways that species may interact in an ecosystem. Apply this knowledge to populations of a local habitat in order to identify and classify the relationships observed (e.g., predator/prey, producer/consumer, parasite/host, and mutualism).
2. Interactions in an ecosystem result from the transfer of matter and energy from producers to consumers and eventually to decomposers. The total amount of matter and energy in the system remains the same even though its form and location changes.
Construct diagrams of food chains to trace the flow of matter in a local ecosystem and to categorize the organisms of the food chain according to the function they serve (e.g., producer, consumer, decomposer). Use several food chains to design a food web (food chains connected together) that would illustrate the interrelationships among the organisms.
3. Matter is recycled in an ecosystem, and energy which enters the system as sunlight is either stored in the bodies of organisms, used by consumers to support their activities, or dissipated to the environment as heat energy. Loss of heat from an ecosystem is compensated for by continuous input of solar energy.
Design food webs that include humans. Discuss how matter is recycled and energy is lost in each step of the food web and the implications of this loss on the food supply for an increasing human population.
Change in Ecosystems
1. Changes in the physical or biological conditions of an ecosystem can alter the diversity of species in the system. As the ecosystem changes, populations of organisms must adapt to these changes, move to another ecosystem, or become extinct.
Investigate local areas (disturbed and undisturbed) that are undergoing natural cycles of succession such as abandoned gardens, uncut areas beneath power lines, areas along ditch banks and fences, and the edge of a forest. Predict how plant communities that grow in the area may change over time and how their presence determine what kinds of animals may move into or out of the area.
Contact the Department of Natural Resources or a wildlife agency to acquire information on animals or plants that have been introduced to Delaware. Investigate issues that relate to the introduction or re-introduction of a species into a local habitat (e.g., How and why the species was introduced into the area? If the species was re-introduced, what previously happened to the animals or habitat to cause their disappearance from the area? What indicators, if any, are there that the transplant was successful?)
2. The size of populations in an ecosystem may increase or decrease as a result of the interrelationships among organisms, availability of resources, natural disasters, habitat changes, and pollution.
Determine the carrying capacity of a single species in a closed system (brine shrimp, fruit fly) by recording the changes in population size over a period of time. Plot the data on a graph and use the results to explain how carrying capacity affects the population growth of the system.
Research and analyze data on human population changes of a specific Delaware area or county in 10 year increments over the last 100 years. Discuss reasons for the increase or decrease in population and how these changes have affected the biodiversity and availability of natural resources.
Technology and Its Influence on the Environment
1. Agriculture relies heavily on technology to increase productivity. Advances in irrigation allow crops to grow in areas where there is not enough precipitation. Chemicals are used to fertilize crops and to control damage done by rodents, fungi, insects, and weeds. The need to increase agricultural production results in environmental trade-offs (e.g., saltwater intrusion, water table lowering, agricultural runoff into rivers/streams, elimination of beneficial insects, desertification).
Investigate the economic and environmental trade-offs involved in implementing agricultural technology as well as farmers’ efforts (e.g., hedge rowing, ditching) to minimize the environmental impact of these technologies.
Interaction of Humans Within Ecosystems
1. The extinction or introduction of species can affect the stability of ecosystems. With careful planning, humans may be able to sustain ecosystems for their use as well as preserve their biodiversity and natural beauty.
Participate in food web demonstrations to predict the environmental impact of eliminating an organism from the food web. Discuss how the elimination or introduction of a species affects the entire ecosystem.
Research and discuss how human interactions have affected different plant and animal populations in Delaware (e.g., deer, phragmities, eagle, osprey, starling, multiflora rose), and explain how population changes have impacted the environment.
Discuss the roles and responsibilities of local, state, and federal environmental agencies. Contact several of these agencies for information on locally rare and endangered plant and animal species. Select a species and gather information about its particular situation (e.g., length of time endangered, past and present range, reasons it is endangered). Report on Delaware efforts to improve the chances of survival for the selected species.
Examine land use maps to identify and classify the uses of land (i.e., agricultural, residential, industrial) for a Delaware community or county. Investigate a specific local land use (e.g., wetlands and shore development, road construction, forestry, farming) and identify how the land use affects both humans and other organisms.
2. Decisions about the use of natural resources are often determined by a society’s short-term needs for the resources with little regard for long-term consequences. The supply of natural resources such as water and petroleum is finite. Non-material resources (e.g., tranquillity, beautiful scenery) can not be easily quantified but must be preserved.
Survey friends, classmates, family, and extended family to determine if differences exist in attitudes about material and non-material resources. Discuss variations in the responses of the people surveyed and why decisions about the use of resources are often complicated and difficult to resolve.
Investigate Delaware’s wetlands as a vital resource and link to maintaining the water quality of the state and construct a wetlands model as follows: Punch many small holes in the bottom of several plastic bottles and fill half-full with different types of soil (e.g., sand, gravel, loam, humus). Place the bottle over an aluminum tray and pour a glass of water on the soil. Collect the drainage and pour the water sample over the soil several more times. Repeat the procedure for the different soil samples, and observe and discuss the changes in water appearance and odor following each treatment. Discuss the ability of wetland soils to filter sediments and pollutants.
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