This guide is for faculty authors, librarians, project managers and others who are involved in the production of open textbooks in higher education and K-12. Content includes a checklist for getting started, publishing program case studies, textbook organization and elements, writing resources and an overview of useful tools.
Students explore the densities and viscosities of fluids as they create a colorful 'rainbow' using household liquids. While letting the fluids in the rainbow settle, students conduct 'The Great Viscosity Race,' another short experiment that illustrates the difference between viscosity and density. Later, students record the density rainbow with sketches and/or photography.
This course provides a broad conceptual and historical introduction to scientific theories of evolution and their place in the wider culture. It embraces historical, scientific and anthropological/cultural perspectives grounded in relevant developments in the biological sciences since 1800 that are largely responsible for the development of the modern theory of evolution by natural selection. Students read key texts, analyze key debates (e.g. Darwinian debates in the 19th century, and the creation controversies in the 20th century) and give class presentations.
Students discover fluid dynamics related to buoyancy through experimentation and optional photography. Using one set of fluids, they make light fluids rise through denser fluids. Using another set, they make dense fluids sink through a lighter fluid. In both cases, they see and record beautiful fluid motion. Activities are also suitable as class demonstrations. The natural beauty of fluid flow opens the door to seeing the beauty of physics in general.
We now know how to analyze pure compounds, but what if we have a mixture? Spectrophometry becomes quite complex when dealing with multiple species of compounds at once. In order to purify a compound we can separate if from a mixture based on its intrinsic chemical properties. Remember that fluorescein is negatively charged at a pH above pKa of the carboxyl group. We can take advantage of this fact and use its attraction to positive charges to separate it from other molecules. In ion-exchange chromatography, we will use a stationary phase with a positive charge, allowing negatively charged molecules to bind and positively charged species to flow through. We can then disrupt this interaction and retrieve our now-purified molecule, and use spectrophotometric analysis of our purified fractions to determine how well we were able to separate our molecules.
Sidereus Nuncius (usually Sidereal Messenger, also Starry Messenger or Sidereal Message) is a short astronomical treatise (or pamphlet) published in New Latin by Galileo Galilei in March 1610. It was the first published scientific work based on observations made through a telescope, and it contains the results of Galileo's early observations of the imperfect and mountainous Moon, the hundreds of stars that were unable to be seen in either the Milky Way or certain constellations with the naked eye, and the Medicean Stars that appeared to be circling Jupiter.
The Latin word nuncius was typically used during this time period to denote messenger; however, it was also (though less frequently) rendered as message. Though the title Sidereus Nuncius is usually translated into English as Sidereal Messenger, many of Galileo's early drafts of the book and later related writings indicate that the intended purpose of the book was "simply to report the news about recent developments in astronomy, not to pass himself off solemnly as an ambassador from heaven." Therefore, the correct English translation of the title is Sidereal Message (or often, Starry Message).
We are all well aware of the composition of the world -atoms form molecules, compound become more complex, and the organization of these atoms into materials with unique structures is what brings about life. As scientists though, we must study these substances , which presents a challenge. How do we study something so incredibly small? One of the simplest methods is spectrophotometry. Different molecules will interact with light in different ways. By studying this, we can quantitatively say both how much light a compound absorbs as well as what kind of light. Certain functional groups tend to absorb light at certain wavelengths, giving "peaks" to the spectrum of light absorption. This lab demonstrates basic principles of absorbance, measured using spectrophotometers.
- Material Type:
- Date Added:
Previously, we showed how different compounds absorb light. The chemical structure of a molecule determines exactly how much light it absorbs, as well as which wavelengths are absorbed. It stands to reason then, that by removing an atom from a molecule, we can change the way it absorbs light. In this experiment, we will relate these two concepts by measuring the absorbance of a molecule under acidic and basic conditions. The changing pH will allow us to find how strongly a specific hydrogen is attached to our molecule, and we will observe how the changing chemical structure affects the observed absorbance. Afterwards, using mathematical analysis, we can experimentally determine the pKa, or affinity of our hydrogen to our parent molecule.