Notas de Presentacion.

Notas de Presentacion

Review 8th ( for Friday, May 22)

Content:

23-1 A Garden in Space p 501

23-2 The Beginning of the Garden. p503

23-3 Breaking Ground. p 507.

24-1 Water Everywhere

The Plant Body p S162

How plant contribute to our lives? Food, shade, beauty, flowers, building materials, medicines.

Biosphere: An area or region where conditions are suitable for living things to survive.

All living things have basic needs that are necessary for their survival regardless of where they are ( food, air, light, and water). In order for people to colonize other planets, an environments similar to the Earth’s must be established.

Germinate: to sprout or begin to develop. Given the right conditions, seeds will develop into plants.

Ferns (Seedless plants) use spore capsules for reproduction.

Gymnosperms (Seed plants) conifers or cone bearing plants, have naked (uncovered) seed and angiosperm (seed plant) flowering plants have covered seed.

Draw and describe the life Cycle of a Plant.

Soil is made up of rock and mineral particles and the decaying remains of living things (organic matter and humus).

Function: Soil provides support for the roots of plants and holds the water, air, and nutrients needed for plant growth.

Soils with fine particles have a greater water holding capacity (amount of water a soil can hold) than soils with coarse particles.

Factors affecting plant growth include soil type, temperature, nutrients, water, and light.

Humus: a part of fertile soil that is derived from the decomposition of living things.

Loam: a mixture of sand, silt, and clay.

Nutrients: chemicals needed for the functioning and growth of living things.

Percolation rate: The speed at which a certain volume of water passes through a sample of soil.

Texture: the feel of soil. What determines the texture of soil? The particle size.

Describe the 3 types of soil (sand, silt, and clay)

Most plant have leaves, stems, and roots and produce flowers.

Leaves produce food by photosynthesis. Are the food making organs of plants. during photosynthesis plants use energy from the sun to convert carbon dioxide and water into sugar and oxygen. Structure of Leaves: blades are thin and flat. Veins bring water and minerals into the leaf. Epidermis is a layer of cells that covers both the upper and lower surfaces of the leaf and prevents the loss of water from inner cells. chloroplast: organelles inside the leaf that absorbs light for photosynthesis. Stomata: Small pores in leaves that allow gases to enter and leave plants. Function of leaves: food making activities, release water inside the plant into the atmosphere.

Stem is the midsection of a plant's body, that in most plants, grows above the ground.

Stem function: hold up the leaves and transport materials through continuous strands of vascular tissue (vascular tissue are groups of water carrying and food carrying cells). Types of Stems: Herbaceous stem: are soft and flexible stems, such as beans, grasses. Woody stems: are stiff and hard, such as trees.

Roots are the part of a plant's body that, in most cases grows under ground.

Roots functions: anchor a plant in the ground, and absorb water and minerals through root hairs. Types of roots: Taproots are large, central roots that grow almost straight down. Most branch, but the branches are much smaller than the main root. Fibrous roots: consist of many thin roots that are all about the same size. often form a dense network near the surface of the soil. they branch extensively and have no single main root. Structure: Root hair: absorbs most of the water (are extensions of the epidermal cells). The growing region of the roots are at the tip of it protected by a root cap.

Stems and roots grow in length by producing new cells at their tips.

Flowers are structures used in reproduction. Perfect flower contain both male and female parts (hermaphrodites). The male part of the flower produces pollen grains which five rise to sperm cells. The female part, produces egg cells. Pollination is the transfer of pollen from a stamen (male part) to a pistil (female part).

Be able to label all the parts of a leaf and flower.

Water enters a plant through its roots and exits through its leaves.

Water moves from one plant cell to another by osmosis.

A plant’s structure permits the distribution of water throughout the plant.

Osmosis: movement of water particles across a semipermeable membrane to areas where water particles are less concentrated.

Photosynthesis: the process in which green plants use sunlight to convert water and carbon dioxide into food. Stomata: Narrow openings in the leaves of a plant through which gases (oxygen, carbon dioxide, water vapor) pass into and out of the plant.

Transpiration: the movement of water out of a plant through the stomata in its leaves.

How does a plant take in water? through the roots (absorption).

How is the water released again into the Earth’s environment? through the stomata in the leaves (transpiration).

What determines the direction that the water move? (osmosis) concentration of solutes.

Review 7th. (for Friday, May 22).

Content:
23-1 How Heat Gets Around. p 420 S165- S167

23-2 Conduction- Heat Transfer Through a Material. p 424

23-3 Convection- Heat Transfer by Currents. p 431.S165-S170

23-4 Radiation- Heat in a Hurry. p 437. S166-S168

Heat always flows from a hotter place to a cooler place.

Conduction occurs when heat flows through a substance or between substances that are in contact with one another Heat transfer by direct contact between heated particles. Radiation occurs when heat travels through empty space or through a transparent material, without heating the space or the material between the heat source and the heated object. Convection: the transfer of heat in a liquid or gas as groups of heated particles move from one region to another. Occurs when heat is transported as a result of the movement of the heated material.

Show how conduction, convection, and radiation can be compared to the way a football is moved around a playing field. (kicking represents radiation, handing the football from player to player represents conduction, and running with the football represents convection). .

Why is it possible to boil the water (on a paper cup) without burning the cup? Heat is conducted through the paper to the water so that both the cup and the water remain at about the same temperature. Water boils at a lower temperature than that at which the cup burns, so the water boils first.

Some materials are better conductors of heat than others. The conduction rate of a material is affected by its composition and size, by the temperature of the heat source, and by the distance of the material from the heat source. Insulator is a material that slows down the flow of heat or carry heat very poorly.

Good conductors of heat include copper, brass, and iron (metals). Poor conductors or insulators are plastic, air, rubber, glass and wood.

Air is a poor conductor of heat. Small air pockets in wool, fur and feathers help to keep heat from passing through these material. As a result, body heat becomes trapped between a person’s body and a garment made from wool, fur, or feather.

Hot or warm air tends to rise, and cold or cool air tends to fall. In a liquid or gas system, convection currents will occur if the temperature is colder at the top of the system than at the bottom of the system. Convection occurs when heat travels as a result of the movement of the material being heated. It is the difference in temperature from one point to another that determines whether convection will occur.

In a sunny day, the air above the land is warmer than the air above the water. The warmer air above the land rises and cooler air from the water moves in, causing the sea breeze. At night the reverse happens. The land becomes cooler than the water. The warmer air above the water rises and the cooler air from the land moves in to take its place. Water can absorb more heat than land and land loses its heat more quickly.

Through what kinds of substances does heat travel by convection? Liquids and gases.

Why doesn’t convection occur in solids? Convection depends on the motion of the material. In a solid the material is not free to move as it is in a gas or liquid.

How is heat transferred from the sun? electromagnetic radiation.

How is the heat from the sun redistributed? By winds and ocean current.

What determines weather and climate? Movement of heat through the oceans, atmosphere and land. Which depends on the angle of the sun’s rays, the density of the atmosphere and the rotation of the Earth.

Greenhouse effect (the trapping of the radiant heat by the Earth’s atmosphere). Infrared waves get trapped by some gases in the atmosphere, such as water vapor, carbon dioxide and methane, causing the Earth to become even warmer.

Two Causes of the increase of carbon dioxide in the atmosphere. Clearing the forest and burning of fossil fuels.

Major contributors to the greenhouse effect: water vapor, carbon dioxide, and methane.

Possible effects of the greenhouse effect: global increase in temperature which could result in a change in the sea level (melting of poles)

Possible solution to the greenhouse effect: Reducing the use of fossil fuels, reducing emission from automobiles and factories. Planting new trees, etc.

Why the earth is not heated evenly? Because of the Earth’s curved shape. Polar regions receive much less solar energy than the regions near the equator.

Convection causes air to move between the Earth’s cold and warm region. Almost all winds are driven by convection patterns that occur because of uneven heating of the Earth’s surface.

What is a convection cell? A complete circle of moving liquid or gas cause by temperature differences. Ex. Cycle of air heating, rising, cooling and returning to the ground.

Role of water in the moderation of the climate. Water is able to store much more heat energy than land. Large bodies of water tend to moderate the climate of nearby areas.

What Hurricanes are? Are giant natural heat engines that feed on the thermal energy contained in tropical seas. These huge storms typically form in the tropics and then veer into the temperate zones, dissipating enormous amounts of tropical heat as they go.

White color reflect most of the radiant energy.

Dark color absorb most the the radiant energy.

TEST 7A and 7B.

Review

Our sense of temperature is no always accurate. Thermometers increase the accuracy with which temperature is measured or gauged.

As the temperature of a substance changes, its physical characteristics may change as well. These changes can be used to measure temperature.

Water boil at 100ªC. It freezes at 0ºC. These temperatures form the basis for the Celsius temperature scale. Highest Temperature on earth ever: 58 ºC (Libya North Africa). Lowest temperature on earth: -88 (Vostok station, Antartica). Surface of the sun: 6000. Center of the Earth: 2000-5000. Atomic explosion. 300 to 400 millions.

Our bodies have many processes for regulating temperature, all of which involve the production or elimination of heat. ex: fevers, goose bumps, sweating, or shivering.

Most thermometers measure temperature by gauging the expansion of a gas or a liquid. There are many different kinds of thermometers, each designed for use in a specific setting.

A thermometer is an instrument used to measure temperature, and it works by undergoing physical changes. Most materials expand when heated and contract when cooled (except water). The most commonly used type of thermometer is base on such change. When a liquid, such as mercury of alcohol, is sealed in and evacuated glass tube, it can be used as a thermometer.

When a thermometer is heated ,its liquid expands more than the glass, so it rises in the tube. Cooling causes the liquid to contract and fall.

Temperature is the hotness or coldness of a material. Measures the warmth of an object.

Heat: Is the energy of the random motion of the molecules in an object. The more heat a substance contains, the faster its molecules are moving on average).

Hot and cold water mixed in equal volumes result in water with a temperature halfway between the two.

Exercises:

-Two parts of at 10 ºC and one part at 40 ºC are mixed, find the average temperature for the mixture (Equal amount ).

-30 ml at 60ºC mixed with 60 ml at 30 ºC. Find the average temeprature of the mixture.

Heat is a form of energy. The joule is the metric unit used to measure energy. It is approximately equal to the amount of energy required to raise a 100 g mass 1 m.

The human body requires a certain number of calories daily in order to function properly. Teenager normaly require 8000 to 10000 Kj per day. About half of this is used to keep your body's basic system running- your heart beating, your lungs breathing, and your brain thinking. The rest is used for movement. If your eat too little, you won't have enough every. If your eat too much, you will put on mass- about 1 kg for every 35,000 KJ. Practice conversion KJ to Calorie. 1 calorie=4.2 KJ. Exercises. Convert 6000 KJ into calories. 10,000 KJ into calories.

What is specific heat? Amount of heat needed to raise the temperature of 1 g of a substance by 1 ºC. Specific heat of water is 4.2 J/g ºC.

- Exercises. 100 g, 1000 g, and 50 g of water. 800 J, 400 J, 200 J. were added. How much would the temperature raise.

TEST 8A and 8B

Review

21-1 Visitors From Space (455) to 22-2 Earth's Place in the Universe (480).

Meteors are lumps of rock or metal that sometimes enter Earth’s atmosphere.

A meteorite is a meteor that strikes Earth’s surface.

Most of the evidence of meteorite impacts on Earth has been destroyed by weathering and erosion.

Comets are frozen masses of water, dust and other materials, that slowly orbit the Sun.

Asteroids: rocks and boulders that have been observed in the solar system. They are different from comets in that they have to tails.

What is shooting stars? Are not stars at all. Are rock particles or dust that had entered the atmosphere. The heat created as the particles streaked through the atmosphere caused the surrounding air to glow white hot, and the meteor burned up before it could reach Earth’s surface.

Where does the word comet comes from? From the Greek word for hair. The material in the tail of a comet gets left in space and can be responsible for meteor showers.

Comets travel around the Sun in an elliptical path. Some make the journey in less than 7 years. Others may travel in such a large orbit that it takes thousand of years to complete the orbit.

The head, or nucleus, of a comet probably consists of ice, dust, and other frozen substances. As a comet approaches the Sun, heat causes the outer layers of the nucleus to vaporize, This vaporization releases the dust and gases that form the tail. A comet’s tail may extend for 160 million kilometers across space. Solar wind pushes the comet’s tail so that it is always pointing away from the Sun.

Asteroids differ from comets in that they are made mostly of rocky materials. As a result, they do not form comet like tails. Most asteroids are found between the orbits of Mars and Jupiter, forming a band called the asteroid belt.

The comet travels at its greatest speed when it is closest to the Sun and at its lowest speed when it is farthest from the Sun.

Permanent space stations and colony on Marx will probably be reality in the next century. – Mars is more like Earth than any of the other planets.

The International Space Station (ISS) is a research facility currently being assembled in Low Earth Orbit. On-orbit construction of the station began in 1998, and is scheduled to be complete by 2011. As of 2009, the ISS is the largest artificial satellite in Earth orbit, larger than any previous space station. It orbits at an altitude of approximately 350 km above the surface of the Earth, travelling at an average speed of 27,700 kilometers per hour, completing 15.7 orbits per day.

Mars Exploration Rover (MER). Once they reach their landing sites, each rover's prime mission will last at least 90 Martian days (92 Earth days). The rovers are solar-powered, and in approximately 90 days, dust slowly accumulating on their solar arrays likely will decrease rover power, bringing to a close each robots sojourn.

- Stars vary in size, color, and temperature. – The color indicate its surface temperature, size and life span. High temperatures are blue-white, low temperatures are red or oranges. (Study table on p S147 (color and temperature) – Stars pass through stages that depend in part on their mass. – The life span of a star is billions of years.

Black hole: a small and dense object formed from a massive collapsing star (supernova) . It has a gravitational pull so strong that even light cannot escape.

Neutron star: a very small star consisting on the remnants of an exploded star. It contains the mass of several Suns, compressed to the size of a small asteroid.

Super giant: a star even larger than a giant star that is very near the end of its life.

Supernova: a high mass star that explodes producing a bright light and leaving behind a neutron star or back hole.

White dwarf: the final stage in the life of low mass stars like the Sun.

Red Giant is a very large and relatively cool star that is nearing its final stages of life. Stars become red giant as they use up their hydrogen and begin burning other fuels.

Neutron stars and black holes begin as very massive stars that explode into supernovas after their red giant stage.

The greater a star’s mass, the brighter it is, the higher tits temperature is, and the faster it uses up its nuclear fuel. Once out of fuel, the star may eventually collapse into a black hole.

The solar system occupies only a tiny part of the universe.

Distances of space are measured in astronomical units and light years. The light from stars in our galaxy was emitted thousand of years ago. The light from other galaxies was emitted millions years ago.

Light year: the distance light travels in one year (about 63,240 AU 0r 9.5 trillion kilometers.) Light travels at 300,000 km/s.