Science Cheerleader

(Thanks, Jessie, for alerting us to this sweet vid!)

A crack team of PhD-trained golden retrievers illustrate the structure of atoms – the particles that make up everything around you. From the creative folks at PetsTeachScience.

#7. The Way a Material Behaves Depends on how its Atoms are Arranged.

Professor James Trefil (author of Science Matters, Why Science?, and 30 other books on science literacy) identified 18 key science concepts every adult should know to be a science literate. We’re here to reintroduce adults to science, in a fun way! It’s all part of our Brain Makeover project to increase adult science literacy. Here’s concept #4, presented by 76ers Cheerleader Lauren and explained by Professor James Trefil.  We’ll post one each week (more or less) and it to the Brain Makeover collection.

The properties of a material depend on the type of bond holding atoms together as well as the arrangement of those atoms. For example, ionic bonds are often found in materials like minerals and ceramics, covalent bonds in the molecules of living systems, and metallic bonds (as the name implies) in metals. The difference between diamond and graphite—both made completely of carbon atoms–depends on the fact that in a diamond those atoms are arranged in a way that all the bonds of covalent, while in graphite some of the bonds are weaker, depending on polarization forces.

The electrical properties of materials depend on how strongly electrons are locked into their bonds. In a metal, for example, electrons are free to respond to outside forces. Such a material is called a conductor, because it allows electrical current to flow. In a plastic or ceramic, on the other hand, electrons are locked tightly into covalent or ionic binds and are not free to move. Such materials are called insulators.

In the twentieth century two other kinds of materials were discovered. Superconductors are materials through which electrical current can flow forever without loss. Normally, materials are superconducting only at low temperatures. Superconducting magnets are used extensively in MRI machines.

Semiconductors (like silicon) are materials in which electrons  are occasionally shaken loose from covalent bonds, and so are available to carry electrical current. Two layers of semiconductors are the basic for solar photovoltaeic cells, in which sunlight shakes loose electrons to create electrical current. A transistor is a triple layer of semiconducting materials and is the basis of modern computers.

Brain Makeover #6: Atoms are Bound by Electron Glue.

Professor James Trefil (author of Science Matters, Why Science?, and 30 other books on science literacy) identified 18 key science concepts every adult should know to be a science literate. We’re here to reintroduce adults to science, in a fun way! It’s all part of our Brain Makeover project to increase adult science literacy. Here’s concept #4, presented by 76ers Cheerleader Lauren and explained by Professor James Trefil.  We’ll post one each week (more or less) and it to the Brain Makeover collection.

Here’s Profession Trefil on Big Idea #6: Atoms are Bound by Electron Glue.
Most of the materials we encounter in our everyday life are compounds, made by putting different combinations of atoms together. The “glue” that holds these molecular together is supplied by the outermost electrons in the atom—chemists call them valence electrons”. There are basically three ways that valence electrons can interact to produce a bind between atoms.

1)  One atom can transfer an electron permanently to another. This is called an ‘ionic’ bond.
2) Two atoms can share a pair of electrons—think of the electrons shuttling back and forth between the atoms. This is called a ‘covalent’ bond.
3) Each atom can give up an electron which is then shared by all the atoms in the material. This is called a ‘metallic’ bond.

In addition, bonds can form when the electrons in a neutral atom tend to cluster in one area, given that a negative charge and leaving other areas with a positive charge.

All Matter is Made of Atoms

Professor James Trefil (author of Science Matters, Why Science?, and 30 other books on science literacy) identified 18 key science concepts every adult should know to be a science literate. We’re here to reintroduce adults to science, in a fun way! It’s all part of our Brain Makeover project to increase adult science literacy. Here’s concept #4, presented by 76ers Cheerleader Lauren and explained by Professor James Trefil.  We’ll post one each week (more or less) and it to the Brain Makeover collection.

#4. All matter is made of atoms.

As the science of chemistry developed in the eighteenth century, it became clear that there are two kinds of  materials in the world: there are materials that can be broken down by chemical means (think of wood burning) and those that cannot. The latter class of materials are called ‘elements’. In the early nineteenth century, it was proposed that to each of these elements, there is a small structure called an atom (the term was borrowed from classical Greek philosophy), and that all the other materials are made by combining atoms.

In the early twentieth century, experiments showed that the atom has a definite structure. In the center is a small, massive, positively charged nucleus, which the electrons circle in orbits. The development of the science of quantum mechanics further showed that electrons can change orbits in the atom, absorbing light when they move away from the nucleus, emitting it when they move in the opposite direction.

His big sister captured this shot after rubbing a balloon on his head. The balloon removed some of the electrons from his hair leaving each with a positive electrical charge. Since charges repulse one another, each hair repulsed the other hair. More on static electricity here.

And, shortly, we’ll learn more about atoms from one of the 76ers Cheerleaders and Professor James Trefil as part of our Brain Makeover initiative.