Science Study Notes-Grade 9

Topics: Electric charge, Electricity, Sun Pages: 6 (1778 words) Published: February 21, 2012
Science Study Notes
An electrically uncharged object is neutral.
Conduction is not a method of charging an object.
If electric charged stay in one spot, they are said to be static. In charging by induction, when a negatively charged rod is brought near a metal leaf electroscope the electrons in the electroscope move away from the rod. A statement that is not part of the Law of Electric Charges is that neutral objects are attracted to uncharged objects. The purpose of a GFCI is to protect people from getting electrocuted. True: Lightning can travel from cloud to cloud. Secondary cells can be recharged. A long wire has a higher resistance than a short wire. False: Cells connected in parallel will make a bulb burn brighter. A voltmeter measures the electric current. Many electrical appliances are over 100% efficient. The difference between a conductor and resistor is that a conductor is a material that lets electrons move freely from atom to atom, while a resistor does not let electrons move freely. Four safety concerns when doing a lab are:

-always read labels on chemicals very carefully
-when doing experiments, follow directions given in the textbook, or given by Ms Bell -make sure caps on bottles are closed tightly to prevent spilling and evaporations -don’t pour chemicals into the sink unless you know it’s safe and you have the teacher’s permission Two types of observations are quantitative (numerical observations) and qualitative (observation including your senses). Mass is the amount of matter in an object. Volume is the amount of space an object takes up. Density is the amount of matter per unit of volume. Malleability-can be hammered into sheets (aluminum is malleable, glass is brittle) Ductility-can be drawn into wires (copper is ductile)

Viscosity- how easily a liquid flows (ketchup is very viscous, and water is not viscous) Boiling Point-when substances vaporize (at or above 100C)
Lustre-shiny or dull
Taste-sweet, sour, salty, bitter, etc.
Texture-gritty, soft, coarse, silky, etc.
Hardness-the measure of the resistance of a solid to being scratched or dented (diamond=hardest) a)3.45cm=0.000345km
Calculate the density of a substance with mass 24.5g and a volume of 240mL.

Calculate the volume of a substance with mass of 34g and density of 2.2 g/mL.

Physical change is a change in the state or form of a substance that does not change the original substance. Chemical change is the alteration of a substance into one or more different substances with different properties. Five states of chemical changes are: when a new colour appears, heat or light is given off, bubbles of gas are found, a solid material forms into a liquid, and the change is difficult to reverse. Combustion is the chemical reaction that occurs when a substance reacts rapidly with oxygen and releases energy. Atoms are tiny particles that are too small to be seen. An element –there are 118 elements on the periodic table- they are made up of atoms. A molecule is the combination or two or more atoms. A compound is made up of elements that combine-they are made up of molecules. Electrolysis is the use of electricity to cause chemical changes in solutions. A)H2SO4=2 hydrogen, 1 sulfur, 4 oxygen.

B)NaCl=1 sodium, 1 chlorine
C)Cu3PO4=3 copper, 1 phosphorus, 4oxygen
D)Mg(OH)2=1 magnesium, 2 oxygen, 2 hydrogen
The horizontal rows in the periodic table are called periods. The vertical rows in the periodic table are called families. Elements are placed in the same family because they all have the same number of electrons of the outer ring. Electricity

Static electricity is a build-up of charge, Static means not moving. Ex. Lightning shocks. The Law of Electric Charges is: opposite charges attract (+ attracts -, - attracts +), similar charge repel (+ and + repel, - and – repel), and natural objects are attracted to charged objects. Charging by...
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