Cell Structure and Function: Cells – The Basis of Life Science Object Average User Rating: Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Cell Structure and Function SciPack. It...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Cell Structure and Function SciPack. It explores the difference between living and non-living things as it looks at the many different types of cells. All self-replicating life forms are composed of cells,-from single-celled bacteria to elephants, with their trillions of cells. Although a few giant cells, such as hens' eggs, can be seen with the naked eye, most cells are microscopic. Multi-celled organisms are composed of many tiny microscopic cells, as opposed to fewer larger cells. Surface area to volume ratio makes efficient food absorption and waste removal possible in cells. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School

A World of Reactions Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Chemical Reactions SciPack. It explains...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Chemical Reactions SciPack. It explains that chemical reactions occur all around us, for example in health care, cooking, cosmetics, and automobiles. An enormous variety of biological, chemical, and physical phenomena can be explained by changes in the arrangement and motion of atoms and molecules. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons. Carbon atoms can bond to one another in chains, rings, and branching networks to form a variety of structures, and complex chemical reactions involving these molecules take place constantly in every cell in living objects. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School

Rates of Chemical Reactions Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Chemical Reactions SciPack. It demonstrates...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Chemical Reactions SciPack. It demonstrates how chemical reactions can take place in time periods ranging from the few femto-seconds (10-15 seconds) required for an atom to move a fraction of a chemical bond distance to geologic time scales of billions of years. The rate of reactions among atoms and molecules depends on how often they encounter one another, which is affected by the concentration, pressure (for gases), and temperature of the reacting substances. The configuration of atoms in a molecule determines the molecule's properties. Shapes are particularly important in determining how large molecules interact with others. Some atoms and molecules called catalysts are highly effective in accelerating chemical reactions. Chemical reactions in living systems are catalyzed by protein molecules called enzymes. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School

Cell Structure and Function: The Molecular Machinery of Life Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of four Science Objects in the Cell Structure and Function SciPack. It...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of four Science Objects in the Cell Structure and Function SciPack. It explores cells at the molecular level. It is at the molecular level that many of the basic functions of organisms are carried out such as, protein synthesis, extraction of energy from food, and replication. All cells have similar types of complex molecules that are involved in these basic activities of life. These macromolecules include proteins, lipids, carbohydrates and nucleic acids, which interact in a soup, about 2/3 water, surrounded by a membrane that controls what can enter and leave the cell. Proteins act in several ways including enzymes that are responsible for catalyzing chemical actions, receptor molecules in the cell membrane, hormones that travel distances to communicate regulatory processes and structurally as the physical fibers of the cell. The cell’s energy comes from food in the form of sugars or from stored fats (lipids). Lipids are also a critical component in the structure of the cell membrane. The cell membrane in association with carbohydrates and proteins, regulate the flow of water, ions, and other molecules into and out of the cells. Nucleic acids contain instructions for genes that determine structural and chemical processes through protein synthesis. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School

Coral Reef Ecosystems: The Abiotic Setting Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of four Science Objects in the Coral Reef Ecosystems SciPack. It investigates...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of four Science Objects in the Coral Reef Ecosystems SciPack. It investigates the abiotic characteristics that affect the coral reef ecosystem. The number and kinds of organisms found along each reef depend on the physical conditions of the environment and resources available, including food, light, water quality, temperature, and other organisms living in the reef. If conditions change significantly due to changes in climate, loss of food sources, excessive predation, or loss of habitat, the health and stability of the ecosystem will be affected. Like many complex systems, coral ecosystems tend to have cyclic fluctuations around a state of rough equilibrium. In the long run, if conditions remain reasonably constant a coral ecosystem can be stable for hundreds of years. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School

Coral Reef Ecosystems: The Living Reef Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Coral Reef Ecosystems SciPack. It explores...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the first of four Science Objects in the Coral Reef Ecosystems SciPack. It explores the unique and diverse ecosystem of the coral reef. Coral reefs are very complex systems that create one of the largest structures on Earth of biological origins. Thousands of coral species exist in oceans worldwide. Reef-building corals remain on the same spot of the sea floor through their entire lives and have developed reproductive, feeding, and social behaviors suited to their situation. As they grow, reefs provide structural habitats for hundreds to thousands of different organisms. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School

Coral Reef Ecosystems: Ecosystems in Crisis Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the fourth of four Science Objects in the Coral Reef Ecosystems SciPack. It explores...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the fourth of four Science Objects in the Coral Reef Ecosystems SciPack. It explores the natural and human causes of ecosystem stress. Human beings live near coral ecosystems and use them in a variety of ways. Increasing amounts of stress is brought on these ecosystems as humans continue to modify the surrounding environment as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening the stability and overall health of many coral reefs. Human activities may also exacerbate the impact of natural disturbances on coral reefs or compromise the ability of the reef to recover from events such as hurricanes, tsunamis, or disease. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School

Coral Reef Ecosystems: Interdependence Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Coral Reef Ecosystems SciPack. It explores...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Coral Reef Ecosystems SciPack. It explores the interdependent relationships between species in the coral reef ecosystem. All populations in the reef ecosystem are a part of and depend on a global food web (a connected set of food chains) through which energy flows in one direction, from the sun into organism and eventually dissipating into the environment as heat. This food web includes ocean plants, the animals that feed on them, and the animals that feed on those animals. Energy is transferred between organisms and their environment along the way. Energy concentration diminishes at each step. The cycles of life continue indefinitely because organisms decompose after death and return food materials to the environment. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School

Science of Food Safety: Microbes, Friend or Foe Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Science of Food Safety SciPack. It explores...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Science of Food Safety SciPack. It explores how bacteria live in close concert with humans. Bacteria are masters at exploiting a variety of niches in the human body and live in huge colonies in places such as the skin, intestines and mouth. Most of these bacteria are harmless to the human body, and many are important in assisting its normal, healthy functioning. Disease in humans results when organisms such as bacteria interfere with the normal operation of the human body, most commonly foreign organisms entering the body. The human body has many mechanisms to protect itself against outside organisms that may interfere with its normal operation. Bacteria that gain entrance to the body may form colonies in preferred organs or tissues, emitting harmful toxins as waste products. If the body's immune system cannot suppress a bacterial infection, an antibacterial drug may be effective—at least against the types of bacteria it was designed to combat. Viruses invade healthy cells and cause them to synthesize more viruses, usually killing those cells in the process. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School

Science of Food Safety: Food Safety and You Science Object Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the last of four Science Objects inthe Science of Food Safety SciPack. It explores...  [view full summary] Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the last of four Science Objects inthe Science of Food Safety SciPack. It explores the scientist involved with the development of germ theory and pasteurization, which brought about great changes in the safe handling of food and water, and improved sanitation measures that represent some of the greatest public health contributions to date. More recently, humans have instituted laws requiring the monitoring of air, soil, and water for microorganisms that pose a threat to human health. Such agricultural and food safety regulations represent social trade-offs that ensure the population's general welfare at the price of increased cost or lowered efficiency. In addition to these large-scale societal precautions, humans rely heavily on personal measures to limit the transmission of invasive organisms into their bodies. These measures include keeping hands and skin clean, avoiding contaminated foods and liquids, cleaning and separating food items properly during preparation, cooking food at high enough temperatures for proper lengths of time, and keeping the temperature of food sufficiently low at all times when it is not being prepared or consumed. [hide full abstract] Member Price: Free Nonmember Price: Free Grade Level: Elementary School, Middle School, High School