revision 3 velocity-time graphs v t 1/.constant acceleration v t 2/.constant velocity v t...
TRANSCRIPT
Revision 3
Velocity-Time GraphsV
t1/.Constant Acceleration
V
t
2/.Constant Velocity
V
t
3/.Deceleration
Velocity-time graphs
80
60
40
20
010 20 30 40 50
Velocity
m/s
T/s
1) Upwards line =
Constant Acceleration
2) Horizontal line =
Constant Velocity
3) Shallow line =
Less Acceleration
4) Downward line =
Deceleration
Force causes a body to change velocity
The unit is called the
Newton (N)A few types
of Forces
Magnetic Force
Tensile Forces
Friction happens when 2 bodies are in contact.
Friction• Friction is the
force that opposes motion of a body when it is in contact with another.
Friction happens when 2 bodies are in contact.
Lubrication reduces friction
There are THREE types of blood vessels
• ARTERIES
• Carry blood away from the heart
• Thick, muscular, stretchy wall
• Narrow central tube
• VEINS• Carry blood towards
the heart• Thin walls with little
muscle• Wide central tube• Have valves stop
the blood flowing backwards
• CAPILLARIES• carry blood between
arteries and veins• wall only one cell
thick• very narrow central
tube
• Thick muscular walls• Divided into 4
chambers• Right side pumps
blood to lungs• Left side pumps
oxygenated blood from the lungs to ALL parts of body
The Blood
• The blood has three main purposes• Transport stuff around the body (Food,
Oxygen, Carbon Dioxide and Urea)• Defence (White Blood Cells)• Clotting (Platelets)
Parts of the Blood
• Plasma – This is the name for the liquid that all the cells float in. Mostly water with Glucose, Protein and Urea dissolved in it.
Parts of the Blood
• Red Blood Cells – Carry the oxygen around the body. The oxygen combines with HAEMOGLOBIN to turn the blood red. When there is no oxygen in the Haemoglobin it turns purple.
Parts of the Blood
• White Blood Cells – Eat the bacteria that invade the body. Forming the main part of the IMMUNE SYSTEM.
• Some can also produce anti-bodies.
Parts of the Blood
• Platelets – Allow the blood to clot by all rushing to the injury.
Excretion
Excretion is the removal of toxic chemical substances
Toxic substances are poisonous and canharm the cells of the body if not removed
Excretion
• Skin - Sweat• Kidneys-Urine• Lungs-Carbon
Dioxide + Water
bladder
urethra
bladder
renal artery
renal vein
ureter
urethra
kidn
ey
Urea is filtered out of the blood mixed with water and excreted as Urine
Atoms
C12
6
Mass Number - Number of protons + Neutrons.
Atomic Number - Number of protons
In a neutral atom the number of electrons and protons are the same. In Carbon it is……… 6
Helium
Neutron
In this atom we see two neutrons and two protons forming the nucleus.
The Neutron has no charge but is the same mass as the proton.
Electron
Proton
Atomic Particles
Particle Charge Mass Where Found
Proton +1 1 amu Nucleus
Neutron 0 1 amu Nucleus
Electron -1 1 amu
1846
Orbiting the
nucleus
Sodium
11 Protons
13 neutrons
24
Na11Group 1 – one electron in last
shell
Electric configuration
2,8,1
Isotopes
• Same number of protons different number of neutrons
Group VII or 0• All in the same group have the same
properties• Group 8/Noble Gases• Non-reactive/Glow with electricity
Non-reactive as they have a full outer shell
Ionic Bonding
• An electron is transferred
Na F
Covalent Bonding
• The electrons are shared
• Elements in the middle of the periodic table
Monomers small molecules that can be joined together.
Polymer is a large molecule made of a chain of smaller molecules
Properties of an Acid
· Tastes sour· Turns blue litmus paper red
· Has a pH of less than 7· Lemon juice and vinegar are good examples.
ACID
Properties of a Base · Turns litmus paper blue· Has a pH greater than 7· taste bitter and have a slippery feel
· Bases that are soluble (dissolve in water) are called alkalis
Most hand soaps and drain cleaners are bases
p Hp H
A measure of how acidic something is
A measure of how acidic something is
IndicatorsThese are chemicals that change colour in the presence of an acid or a base.
We get them from Plants.
All Acid rain is either caused by impurities or not burning fuel well.
Series Circuit -Parallel Circuit
Advantages of parallel circuits…
There are two main reasons why parallel circuits are used more commonly than series circuits:
1) Extra appliances (like bulbs) can be added without affecting the output of the others
2) When one breaks they don’t all fail
Georg Simon Ohm 1789-1854
ResistanceResistance is anything that will
RESIST a current. It is measured in Ohms, a unit
named after me.
The resistance of a component can be calculated using Ohm’s Law:
Resistance = Voltage (in V)
(in ) Current (in A)
V
RI
Wiring a plug
Earth wire
Neutral wire
Insulation
Live wire
Fuse
1.
2.
3.
4.
5.
6. Cable grip
Diode as Valve
• Only allows current in one direction
Forward Bias Reverse Bias
Light Dependent Resistor LDR
• Resistance decreases when light shines on it
• Used to turn on street light
Nerve cells carry information between the CNS and every area of the body…
…nerve cells are very long narrow cells…
…there are two types of nerves cells:
1. SENSORY nerves bring messages from the sense organs to the CNS
2. MOTOR nerves bring messages from the CNS to the muscles of the body
The male reproductive system
The male reproduction system produces and delivers the male gamete (sperm)
link to interactive diagram at Kid’sHealth
Seminal Vesicle
Sperm Duct
Side view
• Occurs when a male gamete (sperm) fuses with the female gamete (egg) to form a zygote
• Also referred to as conception
Sperm + egg = zygote
Fertilisation
• Fertilisation usually happens in the fallopian tube
• A fertilised egg – zygote - then moves down into the wall of the uterus / womb
Fertilisation
© 2005 Chugoku Rosai Hospital
• DNA is what makes a chromosome• A part of the DNA that controls a characteristic is
called a GENES• The gene is the code for any one inherited
character
• DNA stands for deoxyribonucleic acid
• It is twisted into a double helix and contains all the codes to build a body
• the code contains instructions for every structure and function the body will ever need
Weight vs. Mass
• Mass is the amount of matter in us• Same on Earth and Space
• Weight is the pull of gravity on us• Different on Earth and Space
900kg
900kg
9000N 0N
Hookes Law
123456789
1011121314151617181920
Force
Extension
More force means more Extension Force is
proportional to extension
Work Done Lifting• Lift a mass of 80kg a height of
6m.. How much work is done?• Work done = Force x distance
moved
• Work done = 800N x 6m• Work done = 4800 Joules
Pressure – in Fluids
Pressure increases with depth
Atmospheric Pressure• The earth is covered with
layer of Gas.• We are at the bottom of a gas
ocean 200km deep.• The effect of this huge
column of gas is 1 Tonne of weight on our shoulders.
• This is called• ATMOSPHERIC
PRESSURE
Heavy!
Center of Gravity
• The place where all the mass of the body appears to act.
• How do we find the center of gravity of this flat piece of card?
Center of Gravity of a LaminaWe must freely suspend the lamina from three places
Then we trace the plumb line onto the paper.
Center of Gravity
Where all the mass
of the body acts
Moments=Force x Perpendicular distance
FORCE =10N
Perpendicular distance=5m
= 10N x 5m = 50Nm
What is a micro-organism?
An organism which is very small.Examples of micro-organisms:
• Bacteria – e.g. E.coli, Samonella
• Virus - e.g. flu virus, HIV
• Fungi
Micro-organisms need:
• Food• Correct temperature• Suitable medium on which to grow…
Bacteria grow quickly between 300C and 400C
ANTIBIOTICS…these are chemical made by some micro-organisms to kill bacteria.
• Penicillin was ‘discovered’ in 1928 by Sir Alexander Fleming
• White blood cells do the same job.
http://www.uio.no/conferences/imc7/NFotm2000/February2000.htm
Penicillin is produced by the fungus we call ‘blue mould’
BACTERIAL VIRAL
food poisoning cold
septic throat flu
bronchitis AIDS
meningitis can be caused by either
Fungi
• Not all are small• No chlorophyll so live
on organic matter.• Yeast and producing
antibiotics the main uses
• Also athlete’s foot and other poisons
Adding acids to metals
Words – gold, corroded, fizzes, disappears
If an acid is added to a (fairly reactive) metal the metal will be quickly ________ by the acid. We can see a reaction happening because the mixture _________ and the metal eventually __________.
Some metals, like ____, are so unreactive that nothing will happen.
The Reaction
Metals + Acid Hydrogen Gas + Salt
Magnesium + Hydrochloric Hydrogen + Magnesium
Acid Gas Chloride
Mg + 2HCl H2 + MgCl2
Testing for hydrogen
“POP”
Oxygen
• Catalyst speeds up reaction but is not used up – Manganese Dioxide
• Oxygen does not dissolve in the water
Test for Oxygen
• Relights a glowing splint
Adding acid to carbonatesCarbonates are compounds containing carbon and oxygen. When an acid is added to a carbonate the carbonate starts to _______. A gas called ______ _______ is produced.
Carbonates used to be used as building materials but aren’t any more because acid rain would eventually ________ the building.
Words – dissolve, fizz, carbon dioxide
Different Metals in Acid
• Some metals react more than others this
is called the reactivity series
Calcium
Magnesium
Zinc Copper