Notes+to+Study


 * SCIENCE NOTES **

There are three basic types of matter... Solids, Liquids and Gases.
 * Students study these notes for our quizzes on Fridays. ** ** The newest notes are on the bottom. So read and review as you scroll down. **
 * Matter ** is anything that has weight and takes up space.

Matter is made of tiny particles called ** molecules **.

We measure matter in the following ways:
 * __ Mass __** is the amount of matter or molecules matter has and we measure it with a balance in units called grams.

**__ Weight __** is caused by gravity pulling on you. On the moon there is less gravity so you weigh less but your mass stays the same unless you lose molecules!

**__ Density __** is the amount of molecules( mass) in a certain space (volume). To calculate density use this formula: D = M/V or Density is Mass divided by Volume.

Cold water is more dense than hot water.
==== **__ Volume __** is the amount of space matter needs. 50 mL is a measure of volume for a liquid. The volume of a rectangular prism can be calculated by measuring and multiplying length X width X height. ==== For measuring the volume of a marble we pour a certain amount of water in a measuring tube. Then drop in the marble to calculate the water it pushes out of its way. That volume equals the volume of the marble. Check the website here to review these procedures... []

** STATES OF MATTER: ** Chemists study the properties of substances so they can make new materials to help us in many ways. **Matter** is anything that has weight and takes up space. This includes all **solids,liquids and gases**. We proved that air is matter. Using the pan balance we measured the weight of a bottle of air and then pumped the air out and it weighed less.

** Solids **have definite volume and definite shape. Solids have molecules that...are locked in place and vibrate a little. [] ** Liquids ** have molecules that...are close together but slide past each other. Liquids have a definite volume so they cannot be squeezed in to a smaller space. They make good hydraulic lifts. This gives liquids a definite volume but they take the shape of their container. ** Gases ** have molecules that...are free to fly far apart so they fill their container and take any shape. Matter can change phases in the following ways...
 * PHASE CHANGES: **

MELTING - When a solid has enough energy to become a liquid. Most substances have a melting point or temperature where melting takes place.

FREEZING - When a liquid becomes a solid. Most substances have a temperature where freezing occurs.

VAPORIZATION - When a liquid becomes a gas from heating.

Vaporization happens in two ways...

EVAPORATION - Happens slowly at the surface of a liquid. Water vapor is invisible.

BOILING - Happens throughout the liquid and we see bubbles as the liquid becomes a gas.

CONDENSATION - Opposite of vaporization. When a gas becomes a liquid by cooling molecules. Condensation is visible as water drops collect on cold surfaces. Some examples include...fog, clouds, dew, frost, steam and cold bus windows.

SUBLIMATION - Very strange how a solid can become a gas and skip the liquid phase.

This is what happens with Dry Ice.

** What happens in the Water Cycle? **

Water is recycled on Earth by what we call the Water Cycle. Evaporation cleans our water and precipitation helps clean the air.

Energy from the sun evaporates water from the surface of earth. This changes liquid water to a gas or vapor in the air. The water vapor rises until it collects onto dust particles in colder air forming clouds or fog. This is called condensation. Condensation is the opposite of evaporation. The gaseous water becomes a liquid again. If enough water collects there will be rain, sleet or snow. The water returns to earth as precipitation. Plants are part of the water cycle as they absorb and release water back into the air. This is called transpiration. During precipitation some water soaks in the ground and we call this infiltration.

Some runs off the land and causes erosion.

** CLICK HERE IS SEE A WATER CYCLE **

@http://polaris.umuc.edu/cvu/envm/hydro/hydrologic-flash.html

** So, what is air pressure? ** We live at the bottom of an ocean of air and it pushes on us everyday? Normal air pressure is about 15 psi that means every square inch of surface has 15 pounds of air pushing up or down or sideways on it. We saw an aluminum can get smashed by air pressure. We heat an open container and the air can expand out of it then cover quickly and let it cool and SQUISH!!! It gets flattened by air trying to reenter the vacuum. We let air push a balloon in a bottle. We know our canned foods are vacuum sealed by air pressure. We don't really notice it until we create a vacuum or empty space then we see air push all sorts of things into the empty space. Air hates a vacuum space. It pushes to fill it's container. We observed many examples of air pushing never sucking.

See the tanker car implode... []

Try these fun home experiments with parent permission and supervision... [] and... []

Mixtures are made when two or more substances are mixed together. In a mixture the original properties of the substances are still there. Mixtures can be separated. For example you can have a mixture of salt and water. Saltwater is called a solution. Since water can dissolve salt, the water is called a solvent and the salt is the solute. To separate mixtures we use filtration, evaporation, density, solubility and chromatography can separate water based inks as we saw in our lab activity. Crystallization happens when a solution is left to evaporate. For example if saltwater is left out the water evaporates and crystals of salt are left in the dish. Crystals can be very large and very beautiful. Crystals always form perfect geometric shapes because the atoms or molecules of a solute line up in layers as the water molecules slowly vaporize. Snow flakes are another example of crystallization. Chemical reactions happen all around us whenever matter changes and a new substance forms with properties which are different from the properties of the original substance(s). In chemical changes elements can combine to make compounds. Compounds are two or more different types of atoms like Hydrogen and Oxygen. They combine chemically to make water a compound. In class we saw these chemical changes:
 * What is a Mixture? **
 * CHEMICAL vs PHYSICAL CHANGES: **

Electrolysis of water makes oxygen and hydrogen bubbles. electricity can split molecules and make new substances.

Rusting changes iron to iron oxide or rust and it gave off heat so it is an exothermic reaction.

Burning paper is a chemical reaction that is not reversible. Ash and smoke are new products. Vinegar and Baking Soda make a new product called carbon dioxide gas.

When there is a change of state a physical change has occured.

Boiling water is one example. When water boils, gas bubbles to the surface. Even though a gas is produced, since the gas is water vapor (it's still water) there really is no new substance formed. All changes in state are physcial changes.

In class we saw a video of a dangerous chemical reaction to make table salt:

In this reaction the element sodium is combined with chlorine gas to make salt and release heat energy. This is called an exothermic chemical reaction because it gives off heat.

When a chemical reaction occurs, the molecules break apart and the atoms rearrange themselves and recombine forming new substances with different properties from the original substances. This is why they can be dangerous. Chemical reactions happen all around us whenever matter changes and a new substance forms with properties which are different from the properties of the original substance(s).

In class we saw... Electrolysis of water makes oxygen and hydrogen bubbles. Electricity can split molecules and make new substances. Rusting changes iron to iron oxide or rust and it gave off heat so it is an exothermic reaction. Burning a candle is a combustion reaction creating water carbon dioxide and carbon gases.

[|Science Notes.doc]

There are 5 signs that tell us that a chemical reaction may have occurred. They are... 1. Gas production 2. Color change 3. Precipitate formation (a solid forming when two liquids mix together) 4. Temperature increase (exothermic) or decrease (endothermic) 5. Light is given off.

Although these 5 signs indicate that a chemical reaction may have occurred, the only way to know for sure is if a new substance is created. It is possible for any or all of these signs to be present and for the change to actually be physical, not chemical.

ELEMENTS & THE PERIODIC TABLE:

In class we heard how the Greedy King could not make gold...Gold is an element...that means it is made of only one type of atom...gold is made of gold atoms. Copper is made of copper atoms. Hydrogen is made of hydrogen atoms and so on...There are no ingredients for making such pure substances. Each atom of an element is identical.

Water is a compound since it is made of two or more elements bonded.

Compounds like sugar and water are not on the table of elements.

The elements that make them up are there like carbon, hydrogen and oxygen.

Elements are put in order according to their atomic number which equals the number of

protons they contain.

Elements are arranged on the Periodic Table in vertical columns called GROUPS.

GROUPS of elements are like a family sharing similar properties. The first Group all the way on the left side is the Alkali Metal Group or family. These I call the KABOOMERS because they want to bond so rapidly they can explode in water or even exposed to just the air.

Chemist would say they are the most reactive. The last family is the Noble Gas family and they do not form bonds at all.

There are horizontal rows called PERIODS that also share a similarity.

Period 1 has elements that all contain atoms with the same number of electron shells.

Period 2 has atoms that contain 3 electron shells and so on.


 * Atom Building website... **

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 * POWERS OF TEN ...Zoom in from outerspace.... **

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** pH Notes... ** Click here...  [|Acid Rain.doc] [|pHTheChemTool.doc]

Friction between certain surfaces creates static electricity. This happens because negative electrons can be scraped off of atoms. A balloon can steal electrons from atoms of your hair. The balloon becomes negatively charged and sticks to your hair which has the opposite charge of positive. As they stay attracted electrons slowly move back until the neutral surfaces let each other go. Lightning is caused when water molecules and air particles collide. See this power point show with links for more info... [|lightning.ppt] Also see this website... []
 * Static Electricity & Lightning **

The Greeks discovered a natural magnetic rock called magnetite. This amazing stone helped people create magnetic compass needles for navigation. The Earth is a gigantic magnet due to a hot liquid iron outer core under the solid crust. This is called geomagnetism. The earths magnetic field extends far out in space. Animals are affected by the earths magnetic field. We know that birds and many other animals can migrate north and south. We believe that they have some magnetite crystals in their bodies that came from eating iron in their foods and this creates an internal compass that helps them find their way! All magnets have an invisible force field that can be made visible. Remember how we used iron filings to make the field visible. Magnets are stronger at their poles. Each atom inside a magnet is in a position facing the same way. This creates a strong field. If we heat or drop magnets the atoms wiggle out of place and the field weakens. Just like static charges of positive and negative, magnets have a North and a South pole and opposites attract while like repels.
 * Magnetism **

How did we learn about electricty?
 * Current Electricity **

[|http://itp.nyu.edu/~ndl5/electricity/timeline.html#Galvani]

To learn how a battery works click here... []

Also check our... [|cell_assignment.ppt]

Copper atoms can pass their electrons to each other in a wire.Electricity can be made with chemicals in batteries or in power plants using magnets that spin near copper coils.As long as the magnets keep spinning, the electrons will jump from copper atom to copper atom in a wire.Over half of our electricity is made by burning fossil fuels.Fossil fuels include:Coal - made from ancient plants that decayed in swamps.Oil - made from ancient ocean plants and animals that decayedNatural Gas - that bubble up from oil All three of these are flammable and can be burned to boil water to make steam to spin turbines that crank generators to make electricity. The turbines keep the magnets spinning near the copper coils.Electrons get pushed to our homes through transmission lines giving us a continuous flow of electricity.Fossil Fuels are non-renewable which means we will run out of them someday.They also cause pollution. There are other energy resources that are renewable and less polluting such as...Wind Turbines, Wave Turbines, Solar Cells and Solar Mirrors, Nuclear Power, and Hydro-Power Plants Click here to learn more about each resource...
 * __ What is current electricity and how is it created? __** Current electricity is a constant flow of electrons.

[] Also... [] Energy is the ability to move matter. Energy comes in two forms... Potential (stored) & Kinetic (moving) For example...A stretched rubber band has potential energy and when it flies away it has kinetic energy. What other examples did we describe and observe in class?
 * __ What is Energy? __**

Energy also come in 6 basic types...Electrical, Mechanical, Heat, Light, Sound, and Chemical There are many resources to give us energy such as fossil fuels, water, wind, solar and nuclear energy. Some are renewable others are nonrenewable.

Energy is never created or destroyed it only changes form. This is true even when motion stops. For example...Potential energy in a swing can change to Kinetic energy and then to heat energy from friction against air molecules as the swing slows down and stops. The energy is not lost only changed to a different form or type.

WAVES... [] ALSO... [] and one more... [|http://www.absorblearning.com/physics/demo/units/DJFPh063.html#Summary]