28
March
2007
Links to free teaching resources for the story on ballooning spiders
Teaching resources (UK US) designed specifically for this story at www.realscience.org.uk
“Meet a jumping spider named after the character Portia in Shakespeare’s The Merchant of Venice, for her habit of deceiving her enemies. Another jumping spider demonstrates an affinity for watching TV, much to the surprise of arachnologists studying her behavior. Scientist Dave Clark suspects he could be seeing the first stage of an evolving spider species.”
When Gondwana broke up, spiders were isolated on separate continents, where they evolved independently… Spider species are often good travellers. Many of these spiders get around by behaviour called ballooning. “Young spiders, and even small adults of some species, put out silk threads which are caught by the wind, carrying them up and away.”
“Researchers have developed a new model that explains how spiders fly into new territory on single strands of silk – sometimes covering distances of hundreds of miles over open ocean.” Earlier news story on how the Rothamsted scientists developed their ballooning model.
“As you see in this episode, arachnophobia can be treated using virtual reality therapy.” SpiderWorld with virtual spiders.
Lovely series of lessons on spiders for K-3, which pulls together science, math and language. English and Spanish.
Some tiny insects and spiders drift through the sky in the same way that plankton drifts in an ocean. These tiny bugs floating through the air are called “aeroplankton” or “aerial plankton.”
How in the world did spiders get to Hawaii? They floated on air currents! One of the most popular spiders in the world, the Happy Face Spider
“Would you like to adopt a Hawaiian Happyface Spider? These tiny spiders were discovered in 1973 in the rainforests of Hawaii.”
Nice collection of ballooning and Charlotte’s Web activities. “Baby spiders have no wings, but can fly as high as the highest-flying insects and birds! In fact, ballooning spiders often hit airplane windshields. How can a spider, with no wings, possibly get this high in the air? You’ll find out by reading this week’s report and helpful links that follow.”
Links to more
Acorn Naturalists, resources for the trail and classroom.
Spiders and their relatives.
The story:
Soaring spiders
Spiders ride the wind on silken threads. It is called ballooning. They do it to carry themselves out of danger or into new territory. And in the right conditions they can sometimes fly through the air for hundreds of miles.
But nobody knew until now why ballooning reaches a peak in spring and autumn, and is much less common in windy and sunny weather. Sunshine after all produces more updrafts, which are helpful for take-off.
Now a team at Rothamsted Research has developed a model of ballooning. This shows that light breezes and moderately warm weather are the best spider ballooning conditions. This is typical weather for spring and autumn.
These results could lead to a non-chemical alternative to pesticides for managing crops.
The team of biologists and mathematicians used the model to investigate travelling distances under a range of conditions of wind and sun. They were aiming to find the best weather for flight.
Hot days do indeed produce more updrafts. But the wind is not usually strong enough to carry the spiders very far, the scientists found.
On the other hand, if the wind becomes too strong the updraughts are disrupted, the model shows. This makes flight impossible.
Spiders hunt and eat pests like mites and aphids. So predicting spider ballooning peaks is important for crop management.
In the growing season, around 1800 spiders a day land in each hectare of arable farmland after ballooning, explains Dr Andy Reynolds of Rothamsted Research. “If the farmers can predict the influx of spiders, they can reduce the amount of pesticides accordingly.”
The research team is planning field experiments to test the model. This could provide valuable information on other organisms that use the wind for transport. These include mites and viruses.
This research is a good example of interdisciplinary collaboration, said Professor Julia Goodfellow. She is chief executive of the Biotechnology and Biological Sciences Research Council. “Biologists and mathematicians together have produced new knowledge which can help lead to environment-friendly pest control.”
Rothamsted Research is in Hertfordshire, England. It is a sponsored institute of the Biotechnology and Biological Sciences Research Council (BBSRC).
Posted: Biology
26
March
2007
28 Feb 2007 “A new day begins and the mist fades, revealing the teeming tropical forest. For the fog it is time to rest, while other creatures awaken…”
24 Jan 2007 Cloud forest story and science teaching resources (US or UK English) posted at www.realscience.org.uk
Posted: News updates
26
March
2007
14 March 2007 Deep inside Saturn’s moon Enceladus may be an organic brew, a heat source, and liquid water – all the key ingredients for life.
13 March 2007 Methane seas on Titan.
22 March 2007 Enceladus story and science teaching resources (US or UK English) posted at www.realscience.org.uk
Posted: News updates
26
March
2007
20 March 2007 “They may not be gold mines, but the discovery of what appear to be caves on Mars could prove just as rich.”
12 Feb 2007 Martian maps story and science teaching resources (US or UK English) posted at www.realscience.org.uk
Posted: News updates
25
March
2007
4 Dec 2006 Diversified social roles for men, women, and children may have given Homo sapiens an advantage over Neanderthals.
15 Jan 2007 Neanderthal story and science teaching resources (US or UK English) posted at www.realscience.org.uk
15 Nov 2006 Neanderthal story and science teaching resources (US or UK English posted at www.realscience.org.uk
Posted: News updates
25
March
2007
24 March 2007 Ivory-billed woodpecker sought in Texas.
19 March 2007 Researchers at Aberdeen University do not believe reports on the sightings of the ivory-billed woodpecker, believed extinct, in an Arkansas swamp in 2004.
17 Feb 2007 Ivory-billed story and science teaching resources (US or UK English) posted at www.realscience.org.uk
Posted: News updates
24
March
2007
Links to free teaching resources for the story on Saturn’s moon Enceladus:
Teaching resources (UK US) designed specifically for this story at www.realscience.org.uk
Story, audio files, images and podcast from NASA.
Saturn’s tiny moon Enceladus is a “highlight of the Cassini mission and should be targeted in future searches for life.”
Centauri Dreams, one of my favourite blogs, on the topic of little Enceladus. The blog is about the science of star-travelling: “Building a star-faring craft is something like building a cathedral: it will take the combined efforts of scientists and engineers through several generations to make it happen.”
Where is Cassini now?
Make your own Cassini presentation.
Download lesson sets for Reading, Writing and Rings, the Cassini Mission’s language arts and science program for students in grades 1-4.
Without liquid water, terrestrial life could not exist. All living organisms on Earth depend on water and its unique chemical and physical properties. In the search for life beyond Earth, scientists have focused their efforts on looking for signs of liquid water. This essay from NOVA Online explores why liquid water is considered an essential ingredient for life as we know it
Imaginative captain’s log and wonderful images from Cassini
Voyage to the mystery moon. From Nova.
Background on how long is a day on Saturn. Useful for the science methods, but the conclusion is now superseded by this latest story.
More links
NASA resources and information on Enceladus.
NASA image set
Nice explanation of difference between rotation period and length of day. Note that Saturn’s figures are wrong.
Fast facts on Saturn.
The story:
All in a day’s work
How long is a day? Well it depends on where you’re standing. One day is the time it takes for the sun to rotate right around the sky, and come back to the same place. Of course it’s the planet spinning that makes the sun seem to move.
Because planets spin at different rates, each has a different length of day. You might think these numbers would be well known, but not all of them are. Rocky planets are easy. Scientists simply choose a landmark on the surface and wait till it comes round again.
But four planets are made of gas not rock. So finding fixed features on Jupiter, Saturn, Uranus and Neptune is tricky.
Until now a method of measuring radio waves from deep inside these gas giants was thought to be accurate. These radio waves are linked to the planet’s magnetic field. This should rotate at the same rate as the planet.
New data from NASA’s Cassini spacecraft show that things are more complicated at Saturn. The problems are being caused by a small moon called Enceladus. At just over 300 miles in diameter this satellite of Saturn could easily fit into Arizona. It’s a small moon. But it is giving scientists a big headache.
The new data from Cassini show how Enceladus is making it almost impossible to measure the length of Saturn’s day. They demonstrate that the planet’s magnetic field is rotating at a different rate to the planet.
The reason seems to be electrically charged particles coming from huge geysers on Enceladus. These are spewing water vapour and ice.
These results are based on joint observations by two Cassini instruments, the radio and plasma wave instrument and the magnetometer. The new findings are reported online in the 22 March issue of Science
No one could have predicted that Enceladus would have such an effect on the radio technique used to measure the length of Saturn’s day, said Dr. Don Gurnett of the University of Iowa.
Gurnett is the principal investigator on the radio and plasma wave science experiment onboard NASA’s Cassini spacecraft.
What seems to be happening is this. Neutral gas particles are thrown out by geysers on Enceladus. They form a donut-shaped ring around Saturn. As these particles become electrically charged, they are captured by Saturn’s magnetic field. They then form a disk of ionised gas or plasma. This surrounds the planet near the equator.
The scientists now believe that the period Cassini has been measuring from radio emissions is not the length of the Saturn day. Instead it is the rotation of this plasma disk. At present Saturn’s cloud motion means that no technique is known that can accurately measure the planet’s internal rotation.
“We have linked the pulsing radio signal to a rotating magnetic signal,” said Dr. David Southwood, director of science at the European Space Agency. “Once each rotation of Saturn’s magnetic field, an asymmetry in the field triggers a burst of radio waves. We have then linked both signals to material that has come from Enceladus.
The direct link between radio, magnetic field and deep planetary rotation has been taken for granted, said Michele Dougherty of Imperial College London. He is principal investigator on Cassini’s magnetometer instrument.
“Saturn is showing we need to think further.”
Posted: Physics
14
March
2007
Links to free teaching resources for the science story below:
Teaching resources (UK US) designed specifically for this story at www.realscience.org.uk
Set of lessons on gene inheritance: Students learn how genes are passed from one generation to the next. They explore meiosis, which divides the genetic material of an individual in half to produce the sperm or egg cells. They explore how genetic diseases are passed from one generation to the next. A coin-toss exercise demonstrates the odds of parents passing mutated genes to their offspring. Two videos illustrate positive, negative and neutral effects of mutations. From Teachers’ Domain. Simple registration required.
“A mysterious biological mechanism that subtly changes the way people’s genes behave may account for many of the surprising differences between identical twins…” Washington Post. Background on epigenetics.
“Recent revisions to the basic mechanisms of modern genetics violate many long held ideas of inheritance.” Teacher background, since “older textbooks will not have references for these genetic surprises.”
“If you thought that DNA has no secrets left to surrender, think again. The sequencing of the human genome may have heralded a new era for genetic research, but the unravelling DNA story still has a twist in its tail. The new buzzword in many corners of the establishment is epigenetics…”
“How does the environment alter the phenotype? Identical twins are not interesting merely because they are different: everybody’s different. Instead, they are interesting because they show how the same genome can unfold differently with slightly different conditions.” Prominent scientist weblog touching on epigenetics.
“The only important thing about DNA is its sequence, right? Wrong.” Teacher background on epigenetics and methylation.
Activities and instruction on how memory works, and on Alzheimer’s disease. From PBS.
Activity page on memory, with: a minds-on and hands-on experience; an opportunity to compare memory tricks; tools and ideas for improving memory.
The story:
University of Alabama: 14-Mar-2007, 12:00 Eastern US Time, Eurekalert.
Memories are made of this
Scientists have discovered a mechanism by which the constantly changing brain makes its memories—from a dog-bite to that first kiss.
It’s the same mechanism that cells use to alter their genes during development of the embryo.
Neurobiologists Courtney Miller and David Sweatt report their findings in the March 15, 2007 issue of the journal Neuron.
Their studies were aimed at exploring if a process called DNA methylation plays a role in making memories.
In methylation, molecules called methyl groups are attached to genes. This switches them off. Cells use methylation when the embryo is developing to switch off particular genes. This lets the cells specialize into different types – skin, bones, hair, etc – as the embryo grows and develops.
The name for this process is “epigenetic”. Epi means “above” or “in addition”. So epigenetic means that something is happening in addition to the normal action of the genes.
During development of the embryo, methylation causes a permanent change in the activity of genes. Previous studies had hinted that methylation stays active into the adult brain. But it wasn’t thought to be a mechanism for making long-term memories.
On the other hand, mistakes in DNA methylation are seen in some brain disorders, such as schizophrenia.
So Miller and Sweatt designed experiments to test if methylation helps make memories. In their experiments they produced fearful memories in rats. They gave the animals mild shocks when they were in a particular training chamber.
They could then test if the rats remembered, by noticing if they froze when placed in that chamber.
Then they gave the animals drugs that inhibit methylation. This was to test if methylation was needed for the rats to form these memories.
The researchers found that it was. They also found that methylation directly controls the activity of two genes. One of these prevents memories being formed. It is called protein phosphatase 1. The other helps memories form. It is called reelin.
DNA methylation was once thought to be a static process after cell differentiation – when cells had become part of the different organs of the body. This study is the first to find evidence, say the scientists, that instead it is “dynamically regulated in the adult nervous system”, and “plays an integral role in memory formation.”
The new findings show that DNA methylation is used by the central nervous system. This is a key step in controlling gene activity to make memories.
In terms of possible applications of the work, epigenetic errors have been seen in cancer, some types of autism and schizophrenia. So the new findings could improve our understanding of the causes of those disorders.
More broadly, the findings show the importance of DNA methylation in changes in the brain caused by events in the environment
###
The researchers include Courtney A. Miller and J. David Sweatt of University of Alabama at Birmingham in Birmingham, AL.
This work was supported by the NIMH, NINDS, American Health Assistance Foundation, and the Evelyn F. McKnight Brain Research Foundation. C.A.M. is a Civitan Emerging Scholar.
Miller et al.: “Covalent Modification of DNA Regulates Memory Formation.” Publishing in Neuron 53, 857–869, March 15, 2007. DOI 10.1016/j.neuron.2007.02.022. www.neuron.org.
Posted: Biology, Chemistry
11
March
2007
Links to free activities, resources and lesson plans
Teaching resources (UK US) designed specifically for this story at www.realscience.org.uk
“For the very first time, astronomers have witnessed the speeding up of an asteroid’s rotation, and have shown that it is due to a theoretical effect predicted but never seen before.” News release, photos and movies from European Space Observatory.
Online video, teachers’ notes and pupil interactives on near-Earth asteroids.
Earth impact effects program: Provides an easy way to calculate the environmental effects of an asteroid strike on Earth. “Plug in a few size and impact parameters, and find the total damage inflicted with the click of a button.” From University of Arizona.
Interactive lessons and virtual labs on asteroid formation, the physics of asteroid trajectories, etc. “Teachers can also download fun problem-solving activities for use in the classroom.”
Newton’s 3rd Law illustrated through astronauts working working in space. “This video segment, adapted from NOVA, illustrates the significance of Newton’s law to space-walking astronauts and the engineers who design their spacecrafts.”
“Explore the planets, comets and asteroids on an interactive virtual fly-through. Zoom in close on a particular planet or choose a different orbit view to see the whole system from afar. The data sheets let you discover more about some of the elements that make up our Solar System.”
“The University of Pisa offers a comprehensive monthly catalog of known asteroids and other large orbital objects, as well as links to several major observatories.” Enter 2000 PH5 in the search engine to find more facts about the little asteroid than you thought possible.
NASA’s Near Earth Object Program detects, tracks and analyzes large asteroids and comets that might be on a collision course with Earth. Find recent close approaches, view asteroid orbit diagrams, see impact risk assessments. Includes multimedia introduction.
The Asteroid Club encourages amateurs to learn to identify and observe asteroids. “While the deep sky objects observable by amateurs remain the same, year after year, the asteroids are constantly moving against the background of the constellations. By learning to identify asteroids you will greatly enhance your observing skills.”
Background on the YORP effect.
“In 1873, while investigating infrared radiation and the element thallium, the eminent Victorian experimenter Sir William Crookes developed a special kind of radiometer, an instrument for measuring radiant energy of heat and light.”
Posted: Physics
1
March
2007
Links to free activities, resources and lesson plans
Teaching resources (UK US) designed specifically for this story at www.realscience.org.uk
“When Gordon Moore began working at Shockley Semiconductor in 1956, he barely knew what a semiconductor was. Within ten years he was well on his way to being one of the greatest visionaries of the semiconductor world.” Includes audio of Moore talking about the impact of the transistor.
“The Transistor was probably the most important invention of the 20th Century, and the story behind the invention is one of clashing egos and top secret research.” Portal to lots of good stuff for teachers and pupils. For example:
“To help students better understand the transistor and its impact on technology, the documentary and website are accompanied by this Teachers’ Guide… The Teachers’ Guide includes a range of activities, appropriate for middle-school or high-school use, plus a series of profiles of young scientists and their work.
All about Moore’s Law. From Intel.
“This interactive activity from NOVA describes the crystalline structure of metal and uses animations to illustrate the molecular changes that occur when a metallic substance is bent, heated, or otherwise changed by external forces.”
“Einstein’s relativity theory proven with the ‘lead’ of a pencil.” Earlier press release about graphene.
“Researchers have discovered the world’s first single-atom-thick fabric, which reveals the existence of a new class of materials and may lead to computers made from a single molecule.” Original discovery of graphene.
“Graphite, the material that gives pencils their marking ability, could be the basis for a new class of nanometer-scale electronic devices that have the attractive properties of carbon nanotubes – but could be produced using established microelectronics manufacturing techniques.”
“Graphene is a single layer of carbon atoms densely packed in a honeycomb crystal lattice. The material is made from splitting graphite apart into individual atomic planes, through a process similar to tracing with a pencil. The resulting atomic sheet is unexpectedly stable, highly flexible and strong, and very conductive.” Earlier press release about Graphene.
“The structure of a material may be divided into four levels: atomic structure, atomic arrangement, microstructure, and macrostructure.” Page on crystal structures with nice pics and links.
“Materials science and engineering : ‘never heard of it’ is a common enough response both from students at school as well as from the general public. Compared to other science and engineering subjects, it can be a bit of a mystery… However, it is a vitally important subject, underlying all the others and playing a key role in developments in science and technology… most major technological advances throughout history have only been possible through a better understanding and use of materials.”
Links to more links
Transistorized!
Animation gallery of nanotubes, fullerenes etc.
Posted: Physics
