March 31, 2014
Gizmo of the Week: Binomial Probabilities
Before the start of the NCAA Men’s Basketball Tournament, which ends next weekend, Warren Buffett offered a prize of one billion dollars to anyone who could create a perfect bracket. It only took 25 games before the last possible winning entry was eliminated, and Buffett’s money was safe.
How many brackets are possible in the tournament, and what are the chances of creating a perfect bracket? Students can explore these questions with the Binomial Probabilities Gizmo.
In this Gizmo, students use tree diagrams to illustrate the possible outcomes of a series of binomial experiments. Students then derive the formula for finding the probability of r successful outcomes in n experiments.
By the way, there are over 9.2 quintillion (9,200,000,000,000,000) possible brackets in the NCAA tournament. Warren Buffett’s money might be safe for a while!
Use Gizmos to help students understand the science behind the search for the missing Malaysian jetliner
On March 11, Inmarsat, a London-based telecommunication company, contacted Malaysian government with key location information for the missing Malaysian Airlines flight MH370. Inmarsat scientists measured MH370's radar ping against "example" flights to narrow down the search. The more flights they looked at, the smaller their field became, until they were tracked to a remote section of the ocean near Perth.
The company used the 'Doppler effect' to find the area where plane crashed. You're probably familiar with the Doppler effect... when you hear an ambulance pass by, the change in pitch is an example of the Doppler effect.
Watch this Physics teacher explain the Doppler effect and the effect of an object’s movement in relation to the sound waves produced by it: https://www.youtube.com/watch?v=O-Uhiz0Tilk
Help students explore this real world concept with the Doppler Shift Advanced Gizmo. Students can investigate how the speed of the moving object is related to the magnitude of the Doppler shift.
March 19, 2014
Celebrate International Forest Day with Gizmos
Did you know that March 21st is International Forest Day? This global celebration of forests provides a platform to raise awareness of the importance of all types of forests and of trees outside forests. Forests are the most biologically-diverse ecosystems on land, home to more than half of the terrestrial species of animals, plants and insects. Forests also provide shelter, jobs and security for forest-dependent populations.
In celebration of National Forest Day, use the Forest Ecosystem Gizmo to teach students about the delicate balance within a forest ecosystem. Or, have students try out the Measuring Trees Gizmo to investigate how precipitation affects tree growth, while reinforcing mathematic concepts like circumference and diameter.
If you're planning activities for International Forest Day, share them with the community on our Facebook page.
November 02, 2010
Expert's Corner: Understanding Hurricanes
Mario Junco has been with ExploreLearning for four years as a project manager in Miami, Florida. He holds a bachelors degree in Meteorology from Florida State and a Master's Degree in Science Education from Florida International University. Mario taught science for eleven years in Miami Dade and has achieved National Board Certification in Early Adolescent Science.
The Atlantic hurricane season starts June 1st and extends through November 30th each year. Here in Florida, and in other parts of the southern and eastern United States, tropical storms and hurricanes are a threat each year during this time period. The most notable recent example was the 2005 Hurricane Katrina: the sixth strongest overall hurricane in recorded history. It was the most costly natural disaster to date in the United States, causing an estimated $81 billion in property damage. More than 1,800 people lost their lives during the hurricane and subsequent flooding, making it the deadliest U.S. hurricane since the 1928 Okeechobee Hurricane.
Many people in the United States live on or near coastal areas and have to contend with the possibility of these destructive storms each year. Students may wonder how hurricanes form and why their destructive potential is so high. We have several Gizmos that can help you explain concepts related to hurricanes to your students. The Hurricane Motion Gizmo teaches students the real-life skill of tracking hurricanes using latitudinal and longitudinal coordinates.
As a hurricane approaches landfall, weather changes, such as cloud cover, wind speed, wind direction and barometric pressure, start to occur. (As an example, during hurricane Wilma in 2005, the lowest ever recorded barometric pressure of 882 mb was attained). Your students can see how barometric pressure changes by moving a hurricane closer to and further from specific weather stations on the Hurricane Motion Gizmo.
Once students learn about the variables involved in an approaching hurricane, they can conduct an experiment where they attempt to ascertain where an "invisible hurricane" is positioned based on given meteorological data. Teachers can also have students investigate these different weather variables further in the Weather Maps Gizmo and the Coastal Winds and Clouds Gizmo.
The 2004 and 2005 hurricane seasons were extremely active, and many debate hotly whether this increase was due to something meteorologists call a multi-decadal cycle of active seasons or global warming. This topic could be fodder for a great discussion in the science classroom after the students have learned about increasing temperatures in the Greenhouse Effect Gizmo.
Making connections that link current events to science curriculum helps students understand both what's happening in the world and the science behind such events better. For more learning activities related to hurricanes and other weather factors, take a look at the Teacher Guides and Student Exploration Guides with any of the Gizmos mentioned above.
September 07, 2010
Expert's Corner: Back-to-school Inquiry Activities
Bridget Mulvey is a science education doctoral student at the University of Virginia. Bridget holds a master's degree in geological sciences from Indiana University at Bloomington, and she taught middle school, high school and college science before starting her doctoral program. Bridget has taught professional development workshops on scientific inquiry and the nature of science and has presented research on whole class inquiry and the nature of science to researchers and teachers at national conferences.
As school gets back into full swing, teachers seek ways to engage students in science and set the tone for the year. One great way to do this is through scientific inquiry instruction using Gizmos!
Whether you're a pro or just getting started, Gizmos support your efforts to develop a positive classroom environment that facilitates inquiry. The simple and fun Pattern Finder Gizmo is accessible to young students yet can still be a great whole-class warm-up activity for older students.
Students observe, predict and then test predictions to identify patterns in frogs' jumps from lily pad to lily pad. Framing students' investigation with a research question such as, "What patterns can you identify in the frogs' jumps?" is a great first step toward inquiry. Students use observations as evidence that they analyze to answer the initial question.
This minds-on activity requires almost no initial scientific content knowledge and therefore offers all students a chance to be meaningful contributors to the class. This helps students see that science is fun and that they can do it.
Because pattern identification helps us make sense of the natural world, this activity can spark great discussions about the nature of science. For example, you could ask students if it is always possible for scientists to perform experiments. This discussion can highlight that direct experiments are not the only way we learn about the natural world. To learn about things out of our immediate reach, such as Earth's history or the cosmos, we can't control variables to actually experiment. When experiments can be performed, however, they are an essential part of science.
For more content-specific Gizmos appropriate for the beginning of the year, try Density Experiment: Slice and Dice. This updated take on a density lab lets students explore a big misconception about density — that size matters. To make this activity inquiry, pose a question such as, "What relationship does size have to mass, volume and density?"
In this Gizmo, students "slice" off portions of aluminum, wood or other material and compare volume, mass and density for different-sized pieces. Students analyze this information to determine the relationships and thereby answer the research question.
These Gizmos support minds-on investigations that involve students in the processes of science. They also encourage students' input, helping students gain confidence in their scientific abilities. What a great way to begin the school year!
February 02, 2010
Expert's Corner: Earthquakes
Pam Larson is the PD Manager and a national training consultant for ExploreLearning. Pam holds a Master's Degree in Science Education from Northwest Missouri State University and she taught middle and high school science before joining ExploreLearning.
On January 12, a magnitude 7.0 earthquake struck near the Haitian capital of Port-au-Prince. The earthquake caused buildings to collapse throughout the region, including the National Palace, National Assembly, and the Port-au-Prince Cathedral. Estimates of fatalities are higher than 200,000, making it one of the deadliest earthquakes in history. Weeks after the disaster, Haiti still faces a vast crisis in housing and distribution of food supplies.
In the aftermath of the Haiti earthquake, your students may be wondering why an earthquake struck Haiti, and why so many lives were lost. Haiti occupies the western side of the island of Hispaniola. Hispaniola lies on the northern part of boundary between the North American Plate and the Caribbean Plate. This is an example of a transform boundary, where the North American Plate is moving to the west and the Caribbean Plate is moving to the east. Use the Plate Tectonics Gizmo with your students to illustrate four types of plate boundaries and where they occur in the world.
In Haiti, the plate boundary is marked by two parallel faults: the Septentrional Fault and the Enriquillo-Plantain Garden Fault. Like the famous San Andreas Fault in California, these faults are the source of frequent seismic activity. A magnitude 7.5 earthquake struck near Port-au-Prince in 1770, and a magnitude 8.0 earthquake hit the Dominican Republic in 1946.
As the North American Plate grinds past the Caribbean Plate at a rate of about 2 cm per year, stress can build up on faults that are “locked.” Almost 240 years had passed since a major earthquake occurred along the Enriquillo Fault. At the epicenter of the quake (marked in red on the map), the ground ruptured over 4 meters (13 feet)! To help your students learn more about finding the epicenter of an earthquake, use our the Earthquake-Determination of Epicenter Gizmo, which teaches students how to determine the epicenter of the earthquake with real-time charts and the Earthquake-Recording Station Gizmo, which allows student to determine the distance between the recording station and the earthquake, based on timing between seismic waves.
The 2010 Haiti earthquake is comparable in size to the magnitude 6.9 Loma Prieta earthquake that struck northern California in 1989. But, the Loma Prieta earthquake resulted in less than 100 fatalities. Your students may wonder why there was such a disparity in fatalities between the two earthquakes. First, the epicenter of the Loma Prieta earthquake was located in a thinly-populated region north of Santa Cruz, so major population centers were spared the most powerful shaking. Second, buildings in the U.S. are less likely to collapse because of stricter construction rules.
Making connections that link current events to science curriculum helps students understand both what’s happening in the world and the science behind such events better. For more learning activities related to earthquakes, take a look at the Teacher Guides and Student Exploration Guides with any of the Gizmos mentioned above.
ExploreLearning’s parent company, Cambium Learning Group, has responded to the call to support Haiti’s recovery and rebuilding efforts, by contributing $5,000 to the American Red Cross.
March 03, 2009
Expert's Corner: Pi Day
Dan Moriarty is a curriculum writer and editor for ExploreLearning, and our chief Gizmo "demo movie" maker. He holds a Master's degree from the University of Virginia in secondary math education, and he taught high school math before joining ExploreLearning.
The number pi (π) shows up a lot in formulas involving circles. The area of a circle with radius r is A = πr2. The circumference of a circle is C = 2πr (or C = πd).
The value of π as we have all learned, is about 3.14. (In reality, it's a never-ending decimal that starts out 3.14159265358979…) But, how do we know this? How do you come up with the value of π? (And no, I don’t mean "hit the π button on your calculator"!)
I remember doing a classic activity when I was a student in 5th or 6th grade. We all brought in different-sized cans from home. Using string and rulers, we measured the circumference and the diameter of each can and then divided to get the ratio C/d. After putting our results together, we could see that all the ratios C/d were pretty similar (though not exactly the same). I remember thinking that the "right answer" must be 3. In reality, if we could’ve measured perfectly, we should’ve been getting π. But, measuring and eye-balling aren't very precise – particularly in the hands of 11-year-olds!
In the 2nd century B.C.E., Archimedes came up with a clever way to make a very good estimate of π, using areas. The more sides a regular polygon has, the closer it gets to being a circle. Archimedes used two regular 96-gons – one inscribed inside a unit circle (radius = 1), and the other circumscribed around it – to figure out that π (the area of the unit circle) had to be between 223/71 (3.140845…) and 22/7 (3.142857…). That's a gap of only about 0.002 – not bad!
In 1897, a bill introduced in the Indiana General Assembly suggested in a roundabout way that π equals 3.2. That estimate is off by about 0.06, making it about 30 times worse than the estimate made by Archimedes 2000 years earlier! Luckily, this bill was never passed (and – who knows – may still be stuck in committee today).
Today, computers have computed π to over one trillion decimal places, believe it or not. Fortunately for us, it's normally good enough to remember that π is about 3.14. It is from this value that we have Pi Day, March 14 (3/14).
So, have some fun with it and celebrate one of the most important numbers in mathematics! Happy Pi Day, everyone!
February 03, 2009
Expert's Corner: Darwin Day
Kurt Rosenkrantz is science curriculum writer and Gizmo designer for ExploreLearning. Kurt holds a Master of Science in Geology from the University of Cincinnati, and a bachelor's degree in Earth Science from Harvard. He taught high school and middle school science for eight years before joining ExploreLearning.
February 12, 2009 is Darwin Day, the 200th anniversary of Darwin's birth. This year also marks 150 years since the publication of Darwin's seminal treatise, On the Origin of Species, in 1859.
It is extraordinary that this rather shy, cautious, and often-sick man was responsible for the most important scientific revolution in history. Darwin studied to become a doctor and a clergyman, but never completed either of these programs; he preferred to study botany and zoology instead. Darwin's rather aimless life changed dramatically in 1831, when he was hired as ship's naturalist aboard the HMS Beagle.
During the five-year, around-the-world voyage of the Beagle, Darwin observed related species that showed adaptations to different environments. He found fossils of animals that appeared related to modern forms, and observed island animals that were physically similar to mainland forms, but which pursued completely different lifestyles. Darwin gradually became convinced that evolution was the only logical explanation for these patterns.
After returning to England, Darwin puzzled about the mechanisms that could cause organisms to change over time. Darwin found his answer in a book by the economist Thomas Malthus. Malthus predicted that as human populations grew, the competition for resources would become more intense. Darwin realized that as organisms competed for resources, individuals that were born with favorable variations would be more likely to survive, reproduce, and pass on their traits to their offspring. Thus was born the principle of natural selection.
Although he had the framework of his theory in place by 1840, Darwin did not publish his ideas until 1859. In the intervening years, he slowly accumulated evidence from a wide variety of sources, from barnacles to domesticated pigeons. Darwin may have put off publishing indefinitely, but in 1858 he received a nasty shock.
An itinerant beetle collector named Alfred Russell Wallace had written to Darwin, describing his own theory of natural selection.(Although less famous than Darwin, Wallace is generally credited as the co-discoverer of natural selection.) Darwin realized that, after 20 years of work, he was about to be scooped! To his credit, Darwin did not burn Wallace's letter or bury it in the back yard. Instead he arranged that some of his papers, along with Wallace's letter, would be presented to the Royal Society. A year later Darwin published On the Origin of Species, and the rest is history! Today the vast majority of scientists recognize evolution by natural selection as the primary explanation for the diversity of life on Earth.
At ExploreLearning, we have a strong suite of Gizmos focused on evolution. The Rainfall and Bird Beaks Gizmo illustrates how rainfall affects the finch populations that Darwin observed on the Galapagos Islands. Natural Selection allows you to play the role of a bird, hunting for moths camouflaged on the bark of a tree. Evolution: Mutation and Selection and Evolution: Natural and Artificial Selection show a population of beetles that adapt to the color of the leaves they are resting on. Microevolution explores gene frequencies in a population of parrots, and Human Evolution - Skull Analysis allows you to measure and compare the skulls of our own ancient ancestors.
So celebrate Darwin Day, and enjoy the Gizmos!