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"Light" link
Due Date: 1/11/2019
Subject: 8th Grade-Science


Mitosis and Meiosis
Due Date: 1/10/2019
Subject: 7th Grade- Science







Organ Sysytems Intro Link
Due Date: 12/3/2018
Subject: 7th Grade- Science


Cell Membranes and Transport Links
Due Date: 11/29/2018
Subject: 7th Grade- Science

Inside the Cell Membrane

Cell Transport

More waves with Sal Kahn
Due Date: 11/9/2018
Subject: 8th Grade-Science

complete video, practice AND review



Cells b4k
Due Date: 11/6/2018
Subject: 7th Grade- Science



Due Date: 10/31/2018
Subject: 7th Grade- Science

Copy and answer True or False.


1.     Nonliving things have cells.


2.   Cells are made mostly of water.


3.     Different organisms have cells with different structures.


4.     All cells store genetic information in their nuclei.


5.     Diffusion and osmosis are the same process.


6.     Cells with large surface areas can transport more than cells with smaller surface areas.


7.     ATP is the only form of energy found in cells.


8.     Cellular respiration occurs only in lung cells.

Amoeba Sisters - The Grand Tour
Due Date: 10/31/2018
Subject: 7th Grade- Science


Wavy Things
Due Date: 10/30/2018
Subject: 8th Grade-Science

Write True or False


1.     Waves carry matter as they travel from one place to another.


2.     Sound waves can travel where there is no matter.


3.     Waves that carry energy cause particles in a material to move a greater distance.


4.     Sound waves travel fastest in gases, such as air.


5.     When light waves strike a mirror, they change direction.


6.     Light waves travel at the same speed in all materials.

Due Date: 10/19/2018
Subject: 8th Grade-Science


electricity physics4kids
Due Date: 10/3/2018
Subject: 8th Grade-Science



States of Matter Chem4kids
Due Date: 9/17/2018
Subject: 7th Grade- Science


meiosis video
Due Date: 11/13/2017
Subject: 7th Grade- Science



Due Date: 11/9/2017
Subject: 7th Grade- Science



Blue Sky
Due Date: 9/22/2017
Subject: 8th Grade-Science

Why is the sky blue? :: NASA Space Place

A lot of other smart people have, too. And it took a long time to figure it out!

blue sky and clouds illustration


The light from the sun looks white. But it is really made up of all the colors of the rainbow.

A prism separates white light into the colors of the rainbow.

When white light shines through a prism, the light is separated into all its colors. A prism is a specially shaped crystal.

If you visited The Land of the Magic Windows, you learned that the light you see is just one tiny bit of all the kinds of light energy beaming around the universe--and around you!

Like energy passing through the ocean, light energy travels in waves, too. Some light travels in short, "choppy" waves. Other light travels in long, lazy waves. Blue light waves are shorter than red light waves.

Different colors of light have different wavelengths.

All light travels in a straight line unless something gets in the way and does one of these things:—

  • reflect it (like a mirror)

  • bend it (like a prism)

  • or scatter it (like molecules of the gases in the atmosphere)

Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

Atmosphere scatters blue light more than other colors.

Closer to the horizon, the sky fades to a lighter blue or white. The sunlight reaching us from low in the sky has passed through even more air than the sunlight reaching us from overhead. As the sunlight has passed through all this air, the air molecules have scattered and rescattered the blue light many times in many directions.

Atmosphere scatters blue light more than other colors

Also, the surface of Earth has reflected and scattered the light. All this scattering mixes the colors together again so we see more white and less blue.


As the sun gets lower in the sky, its light is passing through more of the atmosphere to reach you. Even more of the blue light is scattered, allowing the reds and yellows to pass straight through to your eyes.

Red sky at sunset

Red sun at sunset.

Sometimes the whole western sky seems to glow. The sky appears red because small particles of dust, pollution, or other aerosols also scatter blue light, leaving more purely red and yellow light to go through the atmosphere.

Photosynthesis in leaves that are not green
Due Date: 9/19/2017
Subject: 7th Grade- Science

Photosynthesis in leaves that aren’t green – 2017 - Michael Ellis

How does photosynthesis occur in plants that are not obviously green, such as ornamental plum trees with deep purple-colored leaves?

Photosynthesis (which literally means “light put together”) is that very elegant chemical process that jump-started life as we know it some 4 billion years ago. So to answer your question, we’ll need a short chemistry lesson. Basically six molecules of water (H2O) plus six molecules of carbon dioxide (CO2) in the presence of light energy produce one molecule of glucose sugar (C6H12O6) and emit six molecules of oxygen (O2) as a by-product. That sugar molecule drives the living world. Animals eat plants, then breathe in oxygen, which is used to metabolize the sugar, releasing the solar energy stored in glucose and giving off carbon dioxide as a by-product. That’s life, in a nutshell.

All photosynthesizing plants have a pigment molecule called chlorophyll. This molecule absorbs most of the energy from the violet-blue and reddish-orange part of the light spectrum. It does not absorb green, so that’s reflected back to our eyes and we see the leaf as green. There are also accessory pigments, called carotenoids, that capture energy not absorbed by chlorophyll. There are at least 600 known carotenoids, divided into yellow xanthophylls and red and orange carotenes. They absorb blue light and appear yellow, red, or orange to our eyes. Anthocyanin is another important pigment that’s not directly involved in photosynthesis, but it gives red stems, leaves, flowers, or even fruits their color.

Many plants are selected as ornamentals because of their red leaves— purple smoke bush and Japanese plums and some Japanese maples, to name just a few. Obviously they manage to survive quite well without green leaves. At low light levels, green leaves are most efficient at photosynthesis. On a sunny day, however, there is essentially no difference between red and green leaves’ ability to trap the sun’s energy. I have noticed the presence of red in the new leaves of many Bay Area plants as well as in numerous tropical species. The red anthocyanins apparently prevent damage to leaves from intense light energy by absorbing ultraviolet light. There is also evidence that unpalatable compounds are often produced along with anthocyanins, which may be the plant’s way of advertising its toxicity to potential herbivores. So red-leaved plants get a little protection from ultraviolet light and send a warning to leaf-eating pests, but they lose a bit of photosynthetic efficiency in dimmer light.

Due Date: 12/5/2016
Subject: 8th Grade-Science

Rare earths: Neither rare, nor earths

22 March 2014 Last updated at 20:40 ET

By Justin Rowlatt BBC World Service


You have probably never heard of most of the rare-earth elements yet they have insinuated themselves deep into the fabric of modern life - in ways of which most of us are completely oblivious.

There are between 15 and 17 of them (depending how you classify them), including such exotic sounding substances as holmium, praseodymium, cerium, lutetium, ytterbium, gadolinium or - my own personal favourite - promethium.

They may be obscure but they have been transforming all sorts of industries. Wind turbine manufacture is a good example.

Henrik Stiesdal is celebrated as one of the fathers of the modern wind industry. He built his first turbine on his family's farm in Denmark as a teenager, and has been perfecting his designs ever since.

Now he's chief technology officer for one of the biggest wind turbine manufacturers in the world, the German engineering giant Siemens.

When you enter his generous office overlooking the company's huge turbine factory on the windswept Jutland peninsula of Denmark, the first thing you notice is the intriguing antique clock opposite his desk.

Its loud ticking is impossible to ignore. He is delighted when I ask about it. It is, he says, an original example of a synchronome clock.

"I bought it to inspire, and because sometimes I feel the need to rub my colleagues' noses in the fact that there are simple solutions to engineering problems people have struggled with for centuries."

Clearly, Stiesdal can be a demanding boss.

The synchronome, designed more than a century ago in Britain, is the most accurate pendulum clock ever built - correct, according to recent studies, to one second every 12 years.

It represents, he explains, an exceptionally elegant answer to the challenge for horologists down the centuries - by reducing the mechanism down to a single gear wheel.

Until very recently Stiesdal and his colleagues faced a similar challenge. They wanted to strip out the gear systems in their turbines.

Wind turbines need gears because the blades turn at about 10 revolutions a minute but the generators that convert that rotation into electricity operate at more like 1,500 revs.

The problem is that - just as with clocks - the more complex a mechanism becomes, the more things can go wrong. And, in the world of wind turbines - particularly offshore turbines - mechanical failure is very expensive. You need specialist crane ships, engineers and good weather. The bill very rapidly runs to hundreds of thousands of dollars.

So how could Stiesdal and his team get rid of all those gears? The industry's solution - as you will have guessed - involves the rare earths.

In his laboratory in University College London, Prof Andrea Sella's face lights up when I ask him about them. Clearly this family of elements is particularly close to the chemist's heart.

"The first thing you need to know is they are neither rare nor earths," he tells me.

They are known as "rare" because it is very unusual to find them in a pure form, but it turns out there are deposits of some of them all over the world - cerium, for example, is the 25th most common element on the planet. The term "earth" is simply an archaic term for something you can dissolve in acid.

They are grouped together as a family because of their incredible chemical similarities - the reason it took a century of chemical investigation to finally isolate them all.

But the rare earths' chemical similarity belies all sorts of fascinating and often very useful electro-magnetic and optical differences.

To demonstrate, Andrea produces a rack of test tubes containing a selection of the rare-earth elements, each one a different pastel shade - there are gentle pinks, purples, blues and greens.

Nitrate salts of 15 of the rare earth elements, known collectively as lanthanides

The radioactive element promethium, is missing from his collection. Andrea calls it the "cuckoo in the nest".

Promethium isn't found naturally on earth, but is formed in nuclear reactors. You may be carrying a tiny trace of promethium now because it has been used in the luminous paint on some watches.

"They tarnish easily in air, they react quite violently, they burn like crazy... But the flipside of that is that once they've burnt and you've made an oxide, that oxide is incredibly robust and stable."

Andrea waves an ultraviolet light over his collection. Some suddenly light up in vivid fluorescent colours.

"One of the incredible properties of the rare-earth elements is that they produce different wavelengths of light - specific colours - exactly on demand," he explains.

It turns out this property forms part of the anti-counterfeiting system used in euro notes.

Andrea takes a 50-euro note from his wallet and places this under the UV light. Bright green and blue stripes and shapes appear together with a constellation of beautiful blue and pinky-purple stars.

"Those stars contain europium," he says, grinning broadly. "This tells me that there is someone with a sense of humour at the beating heart of the European Union."

But the optical properties of the rare earths do more than just deter forgers. The distinctive green light in a television or computer screen is generated using terbium, while the red colour is produced by a combination of europium and yttrium (which is often treated as an honorary member of the rare earths).

But the most useful rare earth - in optical terms - is probably erbium.

The light produced by erbium is out in the near-infrared spectrum and is invisible to the human eye.

But it can send signals down optical fibres for many kilometres, which is why most of the optical fibre applications around the world use signal amplifiers made with erbium.

Rare earths are also essential for the catalytic converters that scrub the exhaust gases of cars clean and in glass polishing.

But it is the incredible magnetic properties of some of the rare earths that most of us - unwittingly - exploit most often.

Andrea passes me a rectangular lump of dark grey metal a few centimetres long.

"Hold this," he orders. I clutch it in my fist.

He produces a two pence coin and places it on the back of my hand.

Even through the thickness of my hand I can feel the magnet tugging at the disk of metal.

"That is a magnet made with neodymium," he explains. "It is 10 times as powerful as a normal iron magnet and can hold 1,000 times its own weight."

Pacemakers sometimes use nuclear batteries containing promethium

It is no exaggeration to say that the miniaturisation of technology would not be possible without these incredible magnets.

They are a surprisingly recent breakthrough. The first magnets using the rare earths neodymium and scandium were developed only in 1982, but their discovery has revolutionised all sorts of technologies.

The tiny motors that power computer hard drives and the miniature speakers on mobile phones and laptops depend on rare-earth magnets.

Neodymium magnets are used in electric guitar pickups, MRI scanners and microwave ovens. You can even buy cufflinks that link up with neodymium magnets.

And they also hold the key to Mr Stiesdal's challenge - getting rid of the huge gear mechanism in wind turbines.

The stronger the magnets, the easier it is to generate power at lower speeds.

An electric current is generated by induction - the electrons are driven as a magnet moves past a coil of wire. The stronger the magnet, the more the electrons move.

Down in one of Siemens' huge engineering sheds below Stiesdal's office, I was shown one of the company's new gearless turbines.

It is much more compact than its forebears. The core is a ring about five metres in diameter, like a giant doughnut, which encloses the axle.

This ring is packed with 648 22cm-long neodymium magnets laced with another rare-earth element, dysprosium, which makes them much less liable to become demagnetised.

It means, Henrik Stiesdal tells me with evident pride, that the same power can be generated without any gear system at all.

The problem is getting hold of the rare earths that make this possible. More than 85% of the world's supply of rare-earth metals comes from China.

And practically 100% of the "heavy" rare earths - at the farther end of the periodic table - come from China, including Stiesdal's dysprosium.

China has some very rich deposits of rare earths in Inner Mongolia. And, until recently, China has not been very squeamish about the consequences of rare-earth extraction.

It is a very dirty business. Rare earths are often found with radioactive elements like thorium and uranium, and separating them out requires a lot of toxic chemicals.

Jack Lifton, founder of Technology Metals Research and an expert on rare earths, describes how, in China, the process of extraction involves leaching out the elements. They flood the high ground with chemicals, he says, and then precipitate out the metals, leaving behind a lake of carcinogenic waste fluids.

In recent years China has been trying to clean the industry up. But it can't actually stop production, because many of the hi-tech industries at the heart of the Chinese economy rely on rare-earth supplies.

Just how dependent the entire world is on Chinese rare earths became very clear at the end of 2010 when China threatened to restrict supplies. The spike in rare-earth prices was very dramatic - up to 3,000% for some of them.

Prices have since fallen back, but the shock was enough to prompt companies to begin to explore producing and refining rare earths elsewhere in the world.

And how did Stiesdal respond to this shock?

"The neodymium exists in large abundance outside China. There are a couple of companies outside China that could keep us running for thousands of years."

And the dysprosium?

"It turns out you can tweak the way you deal with your alloy so you need less. In today's magnets we have 0.7% dysprosium, and in a few years it will be all gone."