how do desert plants survive? (adaptations)

desert plant adaptations:

- reacts rapidly when sufficient rain falls
eg. seeds can germinate, grow up into plants, flower, and repeat the cycle all over again in just 2 weeks. these flowers are called "ephemerals".

- colourful petals
ephemerals have colourful petals to attract desert insects.
-some plants are coated in a certain chemical

- the plants are coated in the chemical in order to prevent them from germinating, until the rain washes the chemical away.

- have shallow widespread root systems
desert succulents (eg. cacti) have such a root system to absorb large amounts of rainwater quickly. This can be stored in the stems of the cacti , some of which are ribbed in order to permit expansion.

- spines on stems
the spines on the stems are to prevent desert animals from taking the stored water.

- cacti takes in carbon dioxide at night and stores it in other chemical compounds.
the stomata are open to allow gaseous exchange when the air is coo, resulting in water loss kept to a minimum. the carbon dioxide is then released and used during photosynthesis.

- a certain species of daisies grows in the desert.

Title of book: eyewitness science-Ecology
Author: Steve Pollock

-smaller leaves

-grow compactly to the ground

-non-porous covering on leaves (eg. wax)

hair on the leaves of the desert plants helps to reduce the evaporation of moisture from the surface of the leaves by reflecting sunlight and inhibiting air movement.

-adapted root system

some plants (phreatophytes) have adapted root systems long enough to reach underground water sources.

-some plants (perennials) survive by becoming dormant during dry periods, then springing to life when water becomes available (eg. ocotillo)

-the leaves of certain plants face directly down or up (eg. spines or fur tree)

the leaves are faced this way so that the amount of heat is reduced resulting in less water evaporating.

-some plants only expose a few of their leaves, most of them are underground along with the main body. (eg. living stones)

this is done so that the plant does not loose all it's water to the sun, the trees are also kept cooler.

bullet train.

since everyone is posting about airplanes, i shall post about a train. (:

The Shinkansen (新幹線^?, new main line), also known as the bullet train, is a network of high-speed railway lines in Japan operated by four Japan Railways Groupcompanies. Starting with the 210 km/h (130 mph) Tōkaidō Shinkansen in 1964, the now 2,459 km (1,528 mi) long network has expanded to link most major cities on the islands of Honshū and Kyūshū at speeds up to 300 km/h (186 mph). Test runs have reached 443 km/h (275 mph) for conventional rail in 1996, and up to a world record581 km/h (361 mph) for maglev trainsets in 2003.

Shinkansen literally means new trunk line, referring to the tracks, but the name is widely used inside and outside Japan to refer to the trains as well as the system as a whole. The name Superexpress (超特急 chō-tokkyū^?), initially used for Hikaritrains, was retired in 1972 but is still used in English-language announcements and signage.

The Tōkaidō Shinkansen is the world's busiest high-speed rail line. Carrying 151 million passengers a year (March 2008), it has transported more passengers (over 6 billion) than any other high speed line in the world. Between Tokyo and Osaka, the two largest metropolises in Japan, up to ten trains per hour with 16 cars each (1,300 seats capacity) run in each direction with a minimum of 3 minutes between trains. Though largely a long-distance transport system, the Shinkansen also serves commuters who travel to work in metropolitan areas from outlying cities.

website:http://en.wikipedia.org/wiki/Shinkansen

how high can you jump and how long can you stay in the air?

But is jumping really flying? Yes and no. Some things like rockets, cannonballs, and baseballs fly like jumping kids_they are pushed into the air by engines or muscles. But what about airplanes? It's true they are pushed forward by engines, but air is what pushes and holds them up. Thrust, drag, weight, and lift are the four forces that usually work together to make things fly. You already know something about each of them, although you might not have called them by their names. If you thought that having stronger muscles or springy shoes or a rocket booster might help your jump, then you were thinking about thrust (the "muscle" that pushes you during flight). If you thought that a slick suit or helmet would make you jump higher or that a parachute would keep you in the air longer, then you were thinking about drag (the way air tends to slow things that fly). Obviously weight is important - if you could lose weight by changing clothes, dieting, or visiting the Moon, you would probably jump higher Most people have experienced how thrust, drag, and weight can help them jump higher or "fly," but few people are familiar withlift. Lift is a push that comes from the air. You were thinking about this force if you decided that wearing wings or holding helium balloons would help you jump higher. Planes and birds have to be moving to get enough of this push to fly; hot-air balloons are light enough for their size that the air will lift them up whether or not the balloon is moving. You may want to find out more about this key force to better understand how things fly. Does everything that flies use all four forces? Nope. Only two forces - weight and thrust - help spacecraft fly. Lift and drag won't help spacecraft flying in space, where no air exists. This was a quick overview of the forces of flight. Don't stop here, though - look for more information about how high you can fly. website:http://www.nasm.si.edu/exhibitions/gal109/lessons/text/look.htm

if you jump up on a moving bus, will you land on the same spot?

You will land in the same place relative to that vehicle, provided that vehicle is going at a constant speed in a constant direction.

You can try this on a train. Make sure you try it when the train is not speeding up, slowing down, or going around a corner. Jump as high as you can, and you should land in basically the same spot on the floor of the train. But if you do it while looking out the window, you will see that you are still passing objects.

This is because of inertia, described by Newton's first law.

"An object in motion will remain in motion unless acted upon by a net force."

So with no wind inside the train, and no-one pushing on you, you will land on the same spot on the floor of the train from which you jumped.

Source: http://en.wikipedia.org/wiki/Law_of_inertia

website:http://wiki.answers.com/Q/If_you_jump_up_and_down_in_a_moving_vehicle_will_you_land_in_the_same_spot_and_why

MEDICINE BALLS.

(this may seem like a really random topic, but i used a medicine ball in netball training yesterday.)

DEFINITION:

A medicine ball (also known as an exercise ball, a med ball, or a fitness ball) is a weightedball roughly the diameter of the shoulders (approx. 14 inches). Often used for rehabilitation andstrength training, it serves an important role in the field of sports medicine. It should not be confused with the larger, inflated exercise ball.

CONSTRUCTION:

medicine balls are generally constructed of a leather or vinyl covered nylon cloth, and filled with impact absorbing materials to give them weight. Vinyl covered medicine balls typically are sand filled and are not used for exercises requiring bouncing. Sand or steel shot filled neoprene bags are also used for medicine ball exercises not requiring bouncing.

Some medicine balls have an inner half sphere of dense material in varying thicknesses and seamed together with an outer rubber shell. Other medicine balls have a thin rubber bladdercovered by a thick rubber outer surface. Medicine balls that are constructed with an inner rubber bladder and rubber outer surface incorporate an air valve to pump up the ball and increase the bounce. The outer rubber surface has indented designs for easy handling. Over time the rubber surface may wear down if the medicine ball has been used on rough surfaces.

Other types of medicine ball include balls made of gel-filled polyvinyl chloride shells, balls made of solid polyurethane, and neoprene bags filled with sand or steel shot. The materials can vary depending on the desired weight and density.

A basketball can be filled with sand, stitched shut, and used as an effective low-price medicine ball where resources are scarce, and is popular in, for example, home "garage" gymnasia.

reflections/ summary for term 2 (:

Physics lessons this term were awesome. they were interesting, yet educational. (: something interesting i learnt this term is that face blotters actually aren't good at all. i had no idea that when you wipe your face with it, your face becomes drier, and results in your face producing more oil! also, i feel that all the videos we watched were interesting and helped me understand the concept of each topic better. an example would be the home alone video helped me understand forces better.

Last but not least, i feel that ESP is a great program and i would love to continue being in it.

LEVERS.

Class 1: the fulcrum is located between the applied force and the load. Example: the crowbar.

Class 2: the load is situated between the fulcrum and the force. Example: the wheelbarrow.

Class 3: the force is applied between the fulcrum and the load. Example: the human elbow joint on flexion.

aviation safety.

Aviation safety has come a long way in over one hundred years of implementation. In modern times, two major manufacturers still produce heavy passenger aircraft for the civilian market:Boeing of the United States of America and the European company Airbus. Both have placed huge emphasis on the use of aviation safety equipment, now a billion-dollar industry in its own right, and made safety a major selling point—realizing that a poor safety record in the aviation industry is a threat to corporate survival. Some major safety devices now required in commercial aircraft involve:

• Evacuation slides — aid rapid passenger exit from an aircraft in an emergency situation.
• Advanced avionics - Computerized auto-recovery and alert systems.
• Turbine engines - durability and failure containment improvements
• Landing gear - that can be lowered even after loss of power and hydraulics.

When measured on a passenger-distance calculation, air travel is the safest form of transportation available: these figures are the ones mentioned by the air industry when quoting statistics on air safety. A typical statement is this one by the BBC: "UK airline operations are among the safest anywhere. When compared against all other modes of transport on a fatality per mile basis air transport is the safest — six times safer than traveling by car and twice as safe as rail."

However, when measured by fatalities per person transported, buses are the safest form of transportation and the number of air travel fatalities per person are surpassed only by bicycles and motorcycles. This statistic is the one used by the insurance industry when calculating insurance rates for air travel.

For every billion kilometers traveled, trains have a fatality rate 12 times larger than air travel, while automobiles have a fatality rate 62 times larger. On the other hand, for every billion journeys, buses are the safest form of transportation. By the last measure air transportation is three times more dangerous than car transportation and almost 30 times more dangerous than bus.

Over 95% of people in U.S. plane crashes between 1983 and 2000 survived. A 2007 study by Popular Mechanics found that passengers sitting at the back of a plane are 40% more likely to survive a crash than those sitting in the front, although this article also quotes Boeing, the FAA and a website on aircraft safety, all claiming that there is no safest seat. The article studied 20 crashes, not taking in account the developments in safety after those accidents. However, a flight data recorder is usually mounted in the aircraft's empennage (tail section), where it is more likely to survive a severe crash.

Where to sit on the plane

While there is some evidence to suggest that the rear of the plane is the safest part, this is by no means always true. Speaking in an interview in January 1973, a survivor of the 1972 Andes crash, Alfredo Delgado, had an ominous feeling that the plane was going to crash and tried to sit in the rear of the plane before take-off, believing that it was the safest spot. He told reporters “I was so convinced that I sat on a seat at the back, because my experience told me that the plane’s tail was much safer than the other parts of the plane.”

After having been told by the cabin crew that the back seats were reserved, Delgado had to move and ended up in a seat in the middle of the plane, “I saved my life by not being seated at the tail, because the tail came off the rest of the plane’s body,” he concluded. Similarly, one of the few survivors of the Madrid plane crash in August 2008, 30 year old Briton Kim Tate Perez, survived the crash because she had been sitting in row 6, the exact spot where the plane ripped in two, throwing her clear of the wreckage.

website:http://en.wikipedia.org/wiki/Aviation_accidents_and_incidents

aviation accidents.

The deadliest aviation-related disaster of any kind, considering fatalities on both the aircraft and the ground, was the destruction of the World Trade Center in New York City on September 11, 2001 with the intentional crashing of American Airlines Flight 11 and United Airlines Flight 175 by Al-qaeda terrorists. The crashes killed 2,988, most of occupants of the World Trade Center towers or emergency personnel responding to the disaster.

A CGI rendering of the two 747s that were destroyed in the Tenerife Disaster.

The March 27, 1977, Tenerife disaster remains the accident with the highest number of airliner passenger fatalities. In this disaster, 583 people died when a KLMBoeing 747 attempted take-off and collided with a taxiing Pan Am 747 at Los Rodeos Airport. Pilot error, ATC error, communications problems, fog, and airfield congestion due to a bombing and a second bomb threat at another airport, which diverted air traffic to Los Rodeos, all contributed to this catastrophe.

The crash of Japan Airlines Flight 123 in 1985 is the single-aircraft disaster with the highest number of fatalities. In this crash, 520 died on board a Boeing 747. The aircraft suffered an explosive decompression from a failed pressure bulkhead repair, which destroyed its vertical stabilizer and severed hydraulic lines, making the 747 virtually uncontrollable.

Turkish Airlines Flight 981

The world's deadliest mid-air collision was the 1996 Charkhi Dadri mid-air collision involving SaudiaFlight 763 and Air Kazakhstan Flight 1907 over Haryana, India. The crash was mainly the result of the Kazakh pilot flying lower than the altitude for which his aircraft was given clearance. Three hundred and forty-nine passengers and crew died from both aircraft. The Ramesh Chandra LahotiCommission, empowered to study the causes, also recommended the creation of "air corridors" to prevent planes from flying in opposite directions at the same altitude.

On March 3, 1974, Turkish Airlines Flight 981 McDonnell Douglas DC-10 crashed in a forest northeast of Paris, France. The destination was London but the plane crashed shortly after taking off from Orly airport. There were a total of 346 people on board; all of them perished in the crash. It was later determined that the cargo door had detached which caused an explosive decompression which in turn caused the floor just above to collapse. When the floor collapsed it severed the control cables, which left the pilots without control of the elevators, the rudder and the No. 2 engine. The plane entered a steep dive and crashed. It was the deadliest plane crash of all time until the Tenerife disaster in 1977.

On June 23, 1985, Air India Flight 182 crashed off the southwest coast of Ireland when a bomb exploded in the cargo hold. On board theBoeing 747-237B were 307 passengers and 22 crew members, all of whom were killed when the plane disintegrated. One passenger checked in as "M. Singh". He didn't board the flight but his suitcase that contained the bomb was loaded onto the plane. Mr. Singh was never identified and captured. It was later found out that Sikh extremists were behind the bombing and that it was a retaliation for the Indian government's attack on the sacred Golden Temple in the city of Amritsar, which is very important for the Sikhs. This was, at the time, the deadliest terrorist attack involving an airplane.

On September 1, 1983, a Soviet Sukhoi Su-15 shot down Korean Air Lines Flight 007 killing all 269 passengers and crew^[1].

Iran Air Flight 655 was a civilian airliner shot down by US missiles on Sunday 3 July 1988, over the Strait of Hormuz killing all 290 passengers and crew aboard, including 66 children, ranking it seventh among the deadliest airline disasters.

Pan Am Flight 103 was a Boeing 747-121 that was destroyed by a terrorist bomb over the town of Lockerbie, Scotland on the 21st December 1988. The crash killed all 243 passengers, all 16 crew and 11 people on the ground (all of whom were residents of Sherwood Crescent, Lockerbie), making it the worst terrorist attack involving an aircraft in the UK.

In August 1985 Delta Air Lines Flight 191 was brought down by a microburst in Dallas Texas. Flight 191 was arriving at DFW around 6 o'clock and entered a thunderstorm just north of DFW. The plane struck the ground the first time in a field just north of the airfield. The plane then bounced back in the air and came down a final time on highway 114. It struck a car killing its driver then went on to smash head on into two huge water tanks.

website:http://en.wikipedia.org/wiki/Aviation_accidents_and_incidents

HIGH HEELS.

some problems caused by wearing high heels:

Stress fractures

cracks or breaks in the bones, more common as we age.

Twisted/sprained/broken ankles

from turning a foot while wearing a high-heeled shoe.

Pump Bump

enlargement of the back of the heel making it stick out and be red or swollen.

Joint pain

especially in the toes and on the balls of the feet, the joint can become chronically irritated and is worsened when heels are worn all the time.

Neuroma

tissue growth under the toes that results in extreme pain.

Back problems

may be related to wearing high heels and having poor postural alignment.

Blistering of the Feet

the shoe rubs the foot the wrong way, pushes two toes together, or otherwise squeezes the toes.

website:http://www.wisegeek.com/what-are-some-problems-caused-by-wearing-high-heels.htm

image website:http://www.google.com.sg/imghp?hl=en

how the moon affects ocean tides.

THE MOON AND TIDES.

The word "tides" is a generic term used to define the alternating rise and fall in sea level with respect to the land, produced by the gravitational attraction of the moon and the sun. To a much smaller extent, tides also occur in large lakes, the atmosphere, and within the solid crust of the earth, acted upon by these same gravitational forces of the moon and sun.What are Lunar TidesTides are created because the Earth and the moon are attracted to each other, just like magnets are attracted to each other. The moon tries to pull at anything on the Earth to bring it closer. But, the Earth is able to hold onto everything except the water. Since the water is always moving, the Earth cannot hold onto it, and the moon is able to pull at it. Each day, there are two high tides and two low tides. The ocean is constantly moving from high tide to low tide, and then back to high tide. There is about 12 hours and 25 minutes between the two high tides.
Tides are the periodic rise and falling of large bodies of water. Winds and currents move the surface water causing waves. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Ocean levels fluctuate daily as the sun, moon and earth interact. As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall. Since the earth is rotating while this is happening, two tides occur each day.What are the different types of TidesWhen the sun and moon are aligned, there are exceptionally strong gravitational forces, causing very high and very low tides which are called spring tides, though they have nothing to do with the season. When the sun and moon are not aligned, the gravitational forces cancel each other out, and the tides are not as dramatically high and low. These are called neap tides.
Spring Tides
When the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. This is known as a spring high tide. Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.

Neap Tides
During the moon's quarter phases the sun and moon work at right angles, causing the bulges to cancel each other. The result is a smaller difference between high and low tides and is known as a neap tide. Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons.

The Proxigean Spring Tide is a rare, unusually high tide. This very high tide occurs when the moon is both unusually close to the Earth (at its closest perigee, called the proxigee) and in the New Moon phase (when the Moon is between the Sun and the Earth). The proxigean spring tide occurs at most once every 1.5 years.

do check out the website for more interesting facts! http://home.hiwaay.net/~krcool/Astro/moon/moontides/

difference between weight and mass.

Difference Between Mass and Weight

Students of physics often confuse mass and weight of an object and many also feel that there is no difference between the two, while the fact is that there is a lot of difference between the two.

Mass is the amount of matter present in a body and is an intrinsic property of the body. Mass of an object remains the same always at any place.

Weight on the other hand is the force which a given mass feels due to the gravity at its place. Weight is measured in units of Force like Newton (which is the SI unit of Force).

If your mass is 60 kgs then your weight is approximately 60 x 10 = 600 Newtons. This is because

Force = mass x acceleration (From Newton's second Law)

Thus, weight = mass x acceleration due to gravity

If you go to moon your mass remains same, i.e 60 kgs, but your weight becomes less by 1/6 amount, since moon's gravity is 1/6 that of earth.

Mass of a body is measured by balancing it equally with another known amount of mass. You keep known amount of masses like blocks of 1 kg, 2 kg etc on one side till both the sides balance and then add up the numbers on the known side of mass and thus calculate the unknown mass. This works because, when the masses are equal on both the sides of the balance the effect of gravity cancels out for both (i.e weight cancels out) and hence we can calculate the mass on one side of the balance if we know the mass on the other side of the balance.

Weight is measured using a scale which effectively measures the pull on the mass exerted by the gravity of the earth.

Table 1: Differences between Mass and Weight

	Mass	Weight
1.	Is always a constant at any place and time	Depends on gravity at the place
2.	Is measured in kilograms in SI unit	Is measured in Newtons (not in kilograms as one might think)
3.	Is measured using balance	Is measured using scales
4.	Can never be zero	Can also be zero
5.	Is an intrinsic property of a body and is independent of any external factor.	Depends on 1. Mass of the object which is attracting it 2. Force with which it is being attracted (which in turn depends on the distance between the two)

If an object is in freefall towards the attractor (like earth), even then it has weight, but it experiences weightlessness (like an astronaut in a spaceship around the earth) since it is obeying the force. Weight can be felt only when the body in question tends to oppose the force of gravity (like u and me sitting on the surface of the earth:-)

Remember that even though we are at rest due to the friction between our self and earth's surface, our acceleration is not zero, it is still 9.8 m/s² as the earth is constantly pulling us down towards its center. But we are resisting that pull and feel the force as weight.

website:http://www.hitxp.com/phy/cph/020902.htm

image fromhttp://www.google.com.sg/images?hl=en&gbv=2&tbs=isch:1&sa=3&q=weight+and+mass&btnG=Search+images

ICEBERGS

An iceberg is a large piece of ice from freshwater that has broken off from a snow-formed glacier orice shelf and is floating in open water. It may subsequently become frozen into pack ice. Alternatively, it may come to rest on the seabed in shallower water, causing ice scour (also known as ice gouging) or becoming an ice island.

Because the density of pure ice is about 920 kg/m³, and that of sea water about 1025 kg/m³, typically only one-tenth of the volume of an iceberg is above water. The shape of the underwater portion can be difficult to judge by looking at the portion above the surface. This has led to the expression "tip of the iceberg", for a problem or difficulty that is only a small manifestation of a larger problem.

Icebergs generally range from 1 to 75 metres (3–250 ft) above sea level and weigh 100,000 to 200 000 tons. The tallest known iceberg in the North Atlantic was 168 metres (550 ft) above sea level, making it the height of a 55-storey building. Despite their size, the icebergs of Newfoundland move an average of 17 kilometres a day (10 mi). These icebergs originate from the glaciers of westernGreenland, and may have an interior temperature of -15 to -20°C (5 to -4 °F).

Though usually confined by winds and currents to move close to the coast, the largest icebergs recorded have been calved, or broken off, from the Ross Ice Shelf of Antarctica. Iceberg B-15, photographed by satellite in 2000, measured 295 km long and 37 km wide (183-23 mi), with a surface area of 11,000 km² (4,250 mi²). The mass was estimated around three billion tonnes.

When an iceberg melts, it makes a fizzing sound called "Bergie Seltzer"". This sound is made when compressed air bubbles trapped in the iceberg pop. The bubbles come from air trapped in snow layers that later became glacial ice.

Ice campers who camp on top of flat or hollowed icebergs are known as icebergers.

SIZE

Names for various sizes of iceberg are not universal, but usually follow a similar pattern. The size classification in the table below is used by the International Ice Patrol:

Size Category	Height	Length
Growler	Less than 1 metre (3.3 ft)	Less than 5 metres (16 ft)
Bergy Bit	1–5 metres (3.3–16 ft)	5–15 metres (16–49 ft)
Small	5–15 metres (16–49 ft)	15–60 metres (49–200 ft)
Medium	15–45 metres (49–148 ft)	60–120 metres (200–390 ft)
Large	45–75 metres (148–246 ft)	120–200 metres (390–660 ft)
Very Large	Over 75 metres (246 ft)	Over 200 metres (660 ft)

source:http://en.wikipedia.org/wiki/Iceberg

source:http://images.google.com.sg/images?hl=en&q=icebergs&um=1&ie=UTF-8&ei=mSDDS7ujCc60rAe91um0CQ&sa=X&oi=image_result_group&ct=title&resnum=1&ved=0CBYQsAQwAA