revision 3 velocity-time graphs v t 1/.constant acceleration v t 2/.constant velocity v t...

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