April 18, we made homemade ice cream from scratch. We took a plastic bag and filled with a cup of milk. Adding 2 spoons of sugar and a few drops of vanilla flavoring, we then zipped the bag to prepare for mixing. We put the creamy substance in another bag filled with ice and rock salt and shook the bigger bag back and forth until the mixture became a solid. Once hard, we were able to eat our resulting product. yum (:

Today, April 22, 2010, using wire and needle-nosed pliers, we created a gas jet unclogger and used it to remove a paper wad from an air jet.

It took 10 minutes to get the paper wad out, and then another 10 minutes to find where it flew off.

SCIENCE: I was able to create this useful tool because the metal of the wire was malleable (bendable and deformable).

chemStd 6b:Students know how to describe the dissolving process at the molecular level by using the concept of random molecular motion

To know how to describe the dissolving process by randomly moving molecules, we first need to know what dissolution is. Dissolution is the process of dissolving a solid substance into a solvent to make a solution. In the picture on the side, we see a solute and solvent breaking into molecules. As the molecules randomly mix, they combine together to create a solution.
When a crystal of salt is dropped into a beaker of water, it is bombarded by randomly moving water molecules which surround each ion and carry it into solution. It is this interaction between moving water molecules and the particles in the crystal that causes it to dissolve. Molecules randomly flow in all directions until there is an equal concentration throughout the solution. Heat speeds up this process. When an ionic compound dissolves in water, the water molecules separate and disperses the ions into the liquid. The positive ions are attracted to the negative ions.

Here's a video that describes sodium chloride being dissolved:

Here's another example of how an ionic compound dissolves in water:

Mills Canyon Map

View Mills Canyon in a larger map

Today we went on a fieldtrip to Mills Canyon. All the students met at 8am. We walked a mile from school uphill. Once we got there, all I could see was trees and dirt. We walked through mud and branches and saw some really cool stuff. During the fieldtrip, we took pictures of cool things we saw and took notes on our white worksheet. All the students were nicely grouped and walked up and down by the stream. We walked in a circle and came back to the entrance around 12. After everyone was regrouped we walked back to school just in time for the sports to go play. We signed in our names and went to our 5th period class.

the toothpick that didnt pop a balloon!

Today I stuck a toothpick into a balloon, and it didn't pop!

The tricks are:
Use a toothpick with a very pointy point
Use the relatively thicker point of the balloon (the rubber "spot" on the very top)
Lubricate the spot AND the toothpick with a small amount of petroleum jelly.
Push the lubricated tip gently into the lubricated spot (not too hard!), and rotate the toothpick as you push. Be patient -- as you push gently and rotate, the rubber will gradually move around the wooden point, and you'll succeed!

SCIENCE: Balloons are made of latex rubber, which is a loosely cross-linked network of long polymer chains. Look at the structure of latex rubber below, and you'll see why the rubber can move around the wooden point and still hold.


How To Stick A Toothpick In A Balloon - Watch a funny movie here

I Propose We Make a Smoke Bomb

Links:
How to Make a Safer Smoke Bomb

Make a Smoke Bomb



The classic smoke bomb is very easy to make, but I know some of you are concerned about the possibility of accidentally setting off your smoke alarm or igniting the mixture during preparation. There is safer way to make a smoke bomb. It uses the same ingredients and produces a comparable amount of smoke, but it takes a bit longer to make. Here's how to make the safer smoke bomb:

Smoke Bomb Ingredients
•potassium nitrate or saltpeter (if you can't find it at a garden store I see Skylighter sells it online)
•sugar (sucrose)
•water
•fuse
•paper or plastic cups
•plastic spoon
•waxed paper

Construct the Smoke Bombs
1.In a paper or plastic cup, mix 3 parts potassium nitrate with 2 parts sugar (e.g., 3 tablespoons potassium nitrate and 2 tablespoons sugar).

2.Using your plastic spoon, stir in just enough water to make a thick paste. Continue stirring until the ingredients are evenly mixed.

3.Set lumps of the mixture (~1 tablespoon each or a little less) onto the waxed paper. Insert a fuse into each lump.

4.Allow the smoke bombs to set up for 1-2 days. The drying time will depend on temperature and humidity. Warmer and drier is faster; cooler and damper will take longer. Keep the smoke bombs away from excessive heat or flame. The smoke bombs will be like clay when they are ready, not hard and solid.

5.Set a completed smoke bomb outdoors on a fireproof surface and light it.

Saftey:
-Wear goggles
-No loose clothing that could get caught
-Wear gloves

OMG WE HAVE A TEST TOMORROW

I'm not ready for this test because Matt Ho is distracting me. I have too much homework and studying to do tonight. AIYAH whatever shall I do? I guess I need to learn how to balance my time and work while dealing with friends and family. This is going to be a tough adjustment but it's a necessary one.

DOMO

So I had a dream about Domo and it made me want things to go back to the way they were. It was really weird because he seemed to have the same dream and texted me about it. All the memories came back and now Matt Ho is sitting next to me and we're talking about our love lives, I mean mine.

Charles's Law

In modern physics, Charles' Law is seen as a special case of the ideal gas equation, in which the pressure and number of molecules are held constant. The ideal gas equation is usually derived from the kinetic theory of gases, which presumes that molecules occupy negligible volume, do not attract each other and undergo elastic collisions (no loss of kinetic energy); an imaginary gas with exactly these properties is termed an ideal gas. The behavior of a real gas is close to that of an ideal gas under most circumstances, which makes the ideal gas law useful.

This law of volumes implies theoretically that as a temperature reaches absolute zero the gas will shrink down to zero volume. This is not physically correct, since in fact all gases turn into liquids at a low enough temperature, and Charles' law is not applicable at low temperatures for this reason.

The fact that the gas will occupy a non-zero volume - even as the temperature approaches absolute zero - arises fundamentally from the uncertainty principle of quantum theory. However, as the temperature is reduced, gases turn into liquids long before the limits of the uncertainty principle come into play due to the attractive forces between molecules which are neglected by Charles' Law.

Boyle's Law

This relationship between pressure and volume was first noted by two amateur scientists, Richard Towneley and Henry Power. Boyle confirmed their discovery through experiments and published the results. According to Robert Gunther and other authorities, it was Boyle's assistant Robert Hooke, who built the experimental apparatus. Boyle's law is based on experiments with air, which he considered to be a fluid of particles at rest, with in between small invisible springs. At that time air was still seen as one of the four elements, but Boyle didn't agree. Probably Boyle's interest was to understand air as an essential element of life [4]; he published e.g. the growth of plants without air [5]. The French physicist Edme Mariotte (1620-1684) discovered the same law independently of Boyle in 1676, but Boyle had already published it in 1662, so this law may, improperly, be referred to as Mariotte's or the Boyle-Mariotte law. Later (1687) in the Philosophiæ Naturalis Principia Mathematica Newton showed mathematically that if an elastic fluid consisting of particles at rest, between which are repulsive forces inversely proportional to their distance , the density would be proportional to the pressure [6], but this mathematical treatise is not the physical explanation for the observed relationship. Instead of a static theory a kinetic theory is needed, which was provided two centuries later by Maxwell and Boltzmann.

redox

Redox (shorthand for reduction-oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane (CH4), or it can be a complex process such as the oxidation of sugar in the human body through a series of complex electron transfer processes.

The term redox comes from the two concepts of reduction and oxidation. It can be explained in simple terms:

* Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom or ion.
* Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom or ion.

Though sufficient for many purposes, these descriptions are not precisely correct. Oxidation and reduction properly refer to a change in oxidation number — the actual transfer of electrons may never occur. Thus, oxidation is better defined as an increase in oxidation number, and reduction as a decrease in oxidation number. In practice, the transfer of electrons will always cause a change in oxidation number, but there are many reactions that are classed as "redox" even though no electron transfer occurs (such as those involving covalent bonds).

Non-redox reactions, which do not involve changes in formal charge, are known as metathesis reactions.

single replacement

In a single replacement reaction, or single displacement reaction, a single uncombined element replaces another in a compound. Two reactants yield two products. For example when zinc combines with hydrochloric acid, the zinc replaces hydrogen. The chemical equation for this single replacement reaction looks like:

Zn + 2HCl ---> ZnCl2 + H2

Some other examples are:

Cu + AgNO3 ---> Ag + Cu(NO3)2

Fe + Cu(NO3)2 ---> Fe(NO3)2 + Cu

Ca + H2O ---> Ca(OH)2 + H2

Decomposition

Decomposition or rotting is the process by which tissues of a dead organism break down into simpler forms of matter. The process is essential for new growth and development of living organisms because it recycles the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death. It is a cascade of processes that go through distinct phases. It may be categorised in two stages by the types of end products. The first stage is characterized by the formation of liquid materials; flesh or plant matter begin to decompose. The second stage is limited to the production of vapors. The science which studies such decomposition generally is called taphonomy from the Greek word taphos, which means grave. Besides the two stages mentioned above, historically the progression of decomposition of the flesh of dead organisms has been viewed also as four phases:

1. fresh (autolysis),
2. bloat (putrefaction),
3. decay (putrefaction and carnivores) and
4. dry (diagenesis).

combustion

Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame. Fuels of interest often include organic compounds (especially hydrocarbon) in the gas, liquid or solid phase.

In a complete combustion reaction, a compound reacts with an oxidizing element, such as oxygen or fluorine, and the products are compounds of each element in the fuel with the oxidizing element. For example:

CH4 + 2O2 → CO2 + 2H2O + energy
CH2S + 6F2 → CF4 + 2HF + SF6

balancing equations

When a chemical reaction occurs, it can be described by an equation. This shows the chemicals that react (called the reactants) on the left-hand side, and the chemicals that they produce (called the products) on the right-hand side. The chemicals can be represented by their names or by their chemical symbols.

Unlike mathematical equations, the two sides are separated by an arrow, that indicates that the reactants form the products and not the other way round.



In this tutorial you will see plenty of chemical equations, both using the names of the chemicals and also their symbols. There is also an exercise at the end if you want to try your hand at balancing chemical equations!



A large number of chemical equations are more complicated than the simple ones you will see in this section. They are reversible, which means that the reactants react together to form the products, but as soon as the products are formed, they start to react together to reform the reactants!

Reversible equations proceed in both directions at once, with reactants forming products and products forming reactants simultaneously. Eventually, the system settles down and a balance (an equilibrium) is reached, with the reactants and products present in stable concentrations. This does not mean that the reaction stops, merely that it proceeds in both directions at the same rate, so that the concentrations do not change.

converting grams to moles

You must first find the molar mass of the element or compound. Use the periodic table (see the Related Link). If the chemical is an element, just read off the atomic mass from the periodic table. If it is a compound, you must know the molecular formula, and then you find the total molar mass of the compound by adding up the atomic masses of each atom in the compound. The unit of the molar mass will be in grams per moles (g/mole).
Once you have the molar mass, you can easily convert from grams to moles, and also from moles to grams.
Number of moles = (# of grams) ÷ (molar mass)
Number of grams = (# of moles) × (molar mass)

Like Dissolves Like

In the right conditions, when solid particles meet liquid particles they can mix together to form a special mixture called a solution. This process is called dissolving. When they do dissolve, the solid part is called the solute and the liquid it dissolves in is called the solvent.



Here is a link that shows a video on dissolving solvents and solutes. http://www.northland.cc.mn.us/biology/BIOLOGY1111/animations/dissolve.html
"Like dissolves like" is an expression used by chemists to remember how some solvents work. It refers to "polar" and "nonpolar" solvents and solutes.

Like Dissolves Like

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