Helium.com | View Helena Whyte's articles http://www.helium.com/users/516994.xml View Helena Whyte's articles en-us Copyright Helium.com Mon, 14 Dec 2009 09:13:45 GMT Mon, 14 Dec 2009 09:13:45 GMT There are several simple methods to determine if a substance is an acid or a base. They are litmus paper, pH paper, phenolphthalein solution, port... http://www.helium.com/items/1681597-how-to-tell-if-a-substance-is-an-acid-or-a-base Mon, 14 Dec 2009 09:13:45 There hasn't been much new in assistive devices for the blind in laboratory equipment in the last thirty years. Chemists can still use an opticon,... http://www.helium.com/items/1681577-lab-equipment-for-the-blind Mon, 14 Dec 2009 08:38:36 John Dalton's Atomic Theory is based on the facts known in 1808. The Atomic Theory states that all elements are made up of atoms. Atoms of an elem... http://www.helium.com/items/1680784-the-basis-of-john-daltons-atomic-theory Sun, 13 Dec 2009 09:59:15 Whether you are a woman driving alone or you are with an elderly or child passenger, there are precautions you can take to ensure your personal sa... http://www.helium.com/items/1680772-personal-safety-for-women-while-driving Sun, 13 Dec 2009 09:32:49 The green chemistry movement started with the ban of phosphates from detergents. Then consumers demanded that detergents perform in cold water. Co... http://www.helium.com/items/1679867-green-chemistry-detergents Sat, 12 Dec 2009 04:58:46 Niels Bohr proposed a model for the hydrogen atom where the negatively charged electron is attracted to the positively charged proton. Bohr said t... http://www.helium.com/items/1679850-neils-bohr Sat, 12 Dec 2009 04:28:45 The Law of Conservation of Mass was established as a basic rule of chemistry from Antoine Lavoisier’s work on combustion. The Law of Co... http://www.helium.com/items/1678012-understanding-the-law-of-conservation-of-mass Thu, 10 Dec 2009 08:10:34 The key to memorization in college is to take advantage of the time provided for the exercise. It is difficult to cram a lot of information in a s... http://www.helium.com/items/1677974-memorization-tips Thu, 10 Dec 2009 07:37:49 The first person to try to organize the chemical elements into patterns was Johann Dobereiner. He grouped families of elements into triads in orde... http://www.helium.com/items/1676909-history-of-the-periodic-table-of-the-elements Wed, 09 Dec 2009 07:36:23 Atoms with the same number of protons but different number of neutrons are called isotopes. Each element found in nature is a mixture of isotopes.... http://www.helium.com/items/1676885-how-isotopes-are-used Wed, 09 Dec 2009 07:03:29 Johannes van der Waals developed a model to explain the behavior of liquids and solids that reflected the size of the atoms or molecules and the s... http://www.helium.com/items/1675766-what-are-van-der-waals-forces Tue, 08 Dec 2009 05:27:18 Ernest Rutherford's 1911 gold foil experiment showed that the positive charge and most of the mass of an atom was found in the center of the atom.... http://www.helium.com/items/1671920-rutherfords-gold-foil-experiment Fri, 04 Dec 2009 08:41:11 A culture must first value its children before it can value education. A nation must first provide adequate nutrition, clean water, and health car... http://www.helium.com/items/1669610-assessing-how-much-a-culture-values-the-education-of-its-children Wed, 02 Dec 2009 08:31:52