Tuesday, November 3, 2015

First Quarter Newsletter

In an effort to increase communication with students, parents, and community members, I would like to do a newsletter blog post every now and then to share what students are learning in our classroom. In September (Chemistry Month), our 7th grade science classes started learning how to use the Periodic Table of Elements.   

If you have access to a computer and the internet, there are a number of excellent tutoring sites to help students gain a better understanding of chemistry.  One of the better sites for middle school students is: chem4kids.com

How do we classify matter?  Matter is anything that has mass and takes up space.  

Scientists use a system to classify matter based on its composition and purity. Matter in its purest form comes in two types – elements and compounds.

The simplest form of matter is an element.  An element is composed of a single kind of atom.  

Gold would be an example of an element, as it is composed of just gold atoms.  If you had a piece of gold, you would just have gold atoms. No other kind of atom would be present.

Compounds are also a pure form of matter, but the particles that make up compounds are composed of more than one kind of atom. These particles are called molecules.  

A molecule is a particle composed of two or more atoms chemically combined. A good example of a compound would be water.  

Water is composed of water molecules, each of which is made up of an oxygen atom and two hydrogen atoms chemically combined.

If you took an element and started subdividing it, you would, after much work, come to the smallest particle that would still have properties of that element.  That particle would be an atom.  

If you took a compound and started subdividing it, you would come to the smallest particle which still has properties of that compound, and that particle would be a molecule. The molecule would be composed of atoms chemically combined.  

To reach an understanding about the nature of matter and chemistry, you need to know something about atoms.

Atoms are very small particles. Atoms are mostly empty space.  

If you enlarged a hydrogen atom so that the nucleus was the size of a person, the electron would be two miles away and the size of a small bird.  It is an interesting thought that if atoms are mostly empty space, we are composed of atoms, so we are mostly empty space.

Atoms are composed of three kinds of particles – electrons, protons, and neutrons.  Protons have a positive charge and a mass of 1 atomic mass unit. Neutrons have no charge (they are neutral) and have a mass of 1 atomic mass unit.  Electrons have a negative charge and have a mass of 1/1840 that of a neutron or proton.  For all practical purposes, in determining the mass of an atom, the masses of the electrons can be neglected as they are so small.

Since atoms are electrically neutral, they will have the same number of protons as electrons – in other words, the same number of positive charges as negative charges.  They are electrically neutral.

Models are used to help us figure out how things work – especially in cases where we can’t actually visualize the objects that we are dealing with.  There are several models of the atom that are used to help us understand how atoms interact.  

One of the simpler models is the one used by Bohr.  He pictured the atoms as a solar system with the nucleus at the center of the atom containing the protons and neutrons and the electrons in orbit about the nucleus.  

Atoms differ from each other in numbers of protons in the nucleus and numbers of electrons in orbit about the nucleus. It is the number of electrons and protons that determines the chemical properties of an element. 

These chemical properties include acidity, flammability, and reactivity. Substances also have physical properties such as density, boiling point, and conductivity. 

These properties are used to identify different substances. Students learn that these substances can change chemically into new substances through reactions in a closed system.

Students raised over $25,000 at our annual Panther Prowl Fundraiser.
Pink Out: Students support Breast Cancer Awareness Month.
Students show their Halloween Spirit.