Students’ investigations of torque

Students come to class with little understanding about torque, angular velocity, and angular acceleration despite the fact that these physical science concepts are frequently observed. For example, torque occurs when car and bicycle tires rotate, the movement of fishing pole when hooking a fish, and when a person uses a hammer to drive in a nail. Interestingly, students also have a plethora of misunderstandings about scientific inquiry. For example, many students believe that all scientific investigations contain an experiment, and that they are all consist of very specific steps comprising the scientific method. In this week long lesson, 9–12 grade students engage in scientific and engineering practices to examine factors that affect the amount of angular acceleration of a catapult arm. Students also reflect on their own understandings of scientific inquiry within the context of the lesson and address misconceptions they might have. Throughout the activities of this lesson, students to engage in discourse, critical thinking, problem solving, reflection, and modification of ideas to design a catapult that will effectively launch a projectile.     

Coastal residents,stingray style: Selecting the best intertidal creeks for seasonal living

Graphing and calculating percentages are integral skills in a STEM curriculum. Teaching students how to create graphs allows them to identify numerical trends and to express results in a clear and concise manner. In this activity, students will remain engaged in the lesson by moving around the room and then work together to generate their own data. Students will act like stingrays and determine the costs and benefits of selecting different habitats. The skills honed in the activity will enable students to compare actual stingray data with in-class data and to express the results graphically. This activity aligns with Ocean Literacy Principles, Common Core Standards, and National Science Education Standards. The Next Generation Science Standard of including the analysis and interpretation of data to provide evidence for the effects of resource availability on organisms in an ecosystem is also incorporated.     

Animal Life in Caves

This is an interdisciplinary lesson designed for middle school students studying landforms and geological processes. Students create a two-dimensional topographic map from a three-dimensional landform that they create using clay. Students then use other groups’ topographic maps to re-create landforms. Following this, students explore some basic ideas about how landforms take shape and how they can change over time. As students work through three distinct learning-cycle phases of concept exploration, introduction, and application, they use art, language arts, and mathematical skills to strengthen or form new science and social studies concepts.     

Thermoelastic excitation of acoustic waves in biological models under the effect of the high peak-power pulsed electromagnetic radiation of extremely high frequency

The capability of high peak-power pulsed electromagnetic radiation of extremely high frequency (35,27 GHz, pulse widths of 100 and 600 ns, peak power of 20 kW) to excite acoustic waves in model water-containing objects and muscular tissue of animals has been experimentally shown for the first time. The amplitude and duration of excited acoustic pulses are within the limits of accuracy of theoretical assessments and have a complex nonlinear dependence on the energy input of electromagnetic radiation supplied. The velocity of propagation of acoustic pulses in water-containing models and isolated muscular tissue of animals was close to the reference data. The excitation of acoustic waves in biological systems under the action of high peak-power pulsed electromagnetic radiation of extremely high frequency is the important phenomenon, which essentially contributes to the understanding of the mechanisms of biological effects of these electromagnetic fields.     

Does It Sink or Float?

ABSTRACT

This activity is designed to teach prekindergarten to second grade students about the concept of sink or float through an inquiry activity. Students will use familiar objects to predict and test the properties of sink and float. Background information is offered to teachers to assist them with this activity. This lesson begins with an engaging story, Who Sank the Boat? by Pamela Allen.     

Exploring the Science of Sound

This investigation-based lesson is geared toward third through fifth grade students. The lesson presented in this article was the first of three lessons designed and taught by us for our first preservice teaching course. UTeach is a teacher preparation program for undergraduate STEM majors, which originated at the University of Austin, Texas. The first course taken by UTeach interns is STEP 1—Inquiry Approaches to Teaching. All UTeach courses promote the use of the 5E (Engage, Explore, Explain, Elaborate, and Evaluate) instructional model. We planned this first lesson by incorporating only Exploration, Explanation, and Elaboration and addressed the most basic principle of sound, which is that sounds are caused by vibrations that travel through some materials (mediums) better than others.     

Electromagnetic hypersensitivity: biological effects of dirty electricity with emphasis on diabetes and multiple sclerosis

Dirty electricity is a ubiquitous pollutant. It flows along wires and radiates from them and involves both extremely low frequency electromagnetic fields and radio frequency radiation. Until recently, dirty electricity has been largely ignored by the scientific community. Recent inventions of metering and filter equipment provide scientists with the tools to measure and reduce dirty electricity on electrical wires. Several case studies and anecdotal reports are presented. Graham/Stetzer (GS) filters have been installed in schools with sick building syndrome and both staff and students reported improved health and more energy. The number of students needing inhalers for asthma was reduced in one school and student behavior associated with ADD/ADHD improved in another school. Blood sugar levels for some diabetics respond to the amount of dirty electricity in their environment. Type 1 diabetics require less insulin and Type 2 diabetics have lower blood sugar levels in an electromagnetically clean environment. Individuals diagnosed with multiple sclerosis have better balance and fewer tremors. Those requiring a cane walked unassisted within a few days to weeks after GS filters were installed in their home. Several disorders, including asthma, ADD/ADHD, diabetes, multiple sclerosis, chronic fatigue, fibromyalgia, are increasing at an alarming rate, as is electromagnetic pollution in the form of dirty electricity, ground current, and radio frequency radiation from wireless devices. The connection between electromagnetic pollution and these disorders needs to be investigated and the percentage of people sensitive to this form of energy needs to be determined.     

Exploring Ethograms in the Schoolyard: A Lesson on Animal Behavior

This article highlights a core lesson that has been used in a number of Lincoln Park Zoo educational programs. The lesson teaches students to conduct an ethological, or animal behavior, study on a bird. This study can be implemented in a variety of outdoor settings, including a park, schoolyard, or zoo. Using an ethogram, students will practice inquiry skills such as making observations, collecting and analyzing data, and sharing results. This type of inquiry-based research is commonly conducted at Lincoln Park Zoo and allows students to make a connection between their work and that of our practicing researchers. Furthermore, this lesson supports the recommendations of the National Research Council by providing students with an opportunity to engage in scientific inquiry and to utilize research skills in an outdoor setting.     

Spectra of Electromagnetic Radiation from a Hot Plasma with Langmuir Turbulence in a Magnetic Field

A study is made of the generation of electromagnetic waves during the merging of two Langmuir plasmons in a hot plasma with a magnetic field. It is shown that the frequency of Langmuir plasmons can vary in the range from 0.8 to 1.1 of the electron Langmuir frequency. The spectrum and polarization of the emitted electromagnetic radiation are analyzed. It is found that the thermal motion of plasma particles may lead to the generation of electromagnetic waves in the frequency range from 1.6 to 2.2 of the electron Langmuir frequency. In a plasma with an isotropic Langmuir turbulence spectrum, the degree of circular polarization of the emitted radiation can amount to 50%.     

Thermoelastic excitation of acoustic waves in biological models exposed to high-peak-power pulsed electromagnetic radiation of extremely high frequency

We experimentally demonstrated for the first time that high-peak-power pulsed electromagnetic radiation of extremely high frequency (35.27 GHz; pulse widths, 100 and 600 ns; peak power, 20 kW) is capable of thermoelastic excitation of acoustic waves in model water-containing objects and muscle tissue of animals. The amplitude and duration of excited acoustic pulses are within the limits of accuracy of theoretical estimates and are a complex nonlinear function of electromagnetic energy input. The propagation velocities of acoustic pulses in water-gelatin models and isolated muscle tissue of animals are close to reference data. The excitation of acoustic waves in biological systems exposed to high-peak-power pulsed microwaves is an important phenomenon that makes an essential contribution to understanding the mechanisms of biological effects in these electromagnetic fields.     

Watts down is What's Up

Physics instruction looks different from one classroom to the next; however, the outcome of those classrooms should be one and the same. Students should understand simple concepts and be able to transfer concepts to more complex problems. In this lesson, I would like to show you how I provide students an opportunity to explore their ideas before formulae or calculations are introduced.     

Generation of terahertz radiation from a low-density plasma slab irradiated by a laser pulse

The generation of terahertz electromagnetic radiation when a laser pulse propagates through a low-density plasma slab is considered. It is shown that terahertz waves are excited because of the growth of a weakly damped, antisymmetric leaking mode of the plasma slab. The spectral, angular, and energy parameters of the terahertz radiation are investigated, as well as the spatiotemporal structure of the emitted waves. It is demonstrated that terahertz electromagnetic wave fields are generated most efficiently when the pulse length is comparable to the slab thickness.     

Polarization of electromagnetic radiation at the second harmonic of the electron gyrofrequency in a turbulent plasma

A study is made of the polarization of electromagnetic radiation at the second harmonic of the electron gyrofrequency. The radiation is emitted by a highly ionized collisionless plasma in which the turbulence is excited at electron gyrofrequencies in a strong magnetic field. The mechanism for the generation of electromagnetic waves during mergings of the gyrofrequency plasmons is analyzed. It is shown that, even in a strong magnetic field, the degree of circular polarization of electromagnetic radiation at the second harmonic of the electron gyrofrequency may be moderate or weak.     

Spontaneous electrical activity of the rat cerebral cortex during microwave irradiation

A study was made of changes in spontaneous electrical activity of rat brain cortex induced by a single exposure to microwave radiation (electromagnetic fields of 0.1, 1.0, 10, and 35 mW/cm2). The animals were exposed in anechoic chambers to continuous waves at 2450 MHz in conditions of continuous generation. The data obtained indicate that the EEG parameters change under the effect of microwave radiation. The technique applied permits to study the occurrence and development of the CNS reactions to microwave radiation at the time of action of the factor.     

The Judicious Use of Instructional Technology in Science Education

It is natural to study astronomy outdoors, but it is not quite as natural to study astronomy during the daytime. This lesson uses the Earth's closest star as a subject of study within the schoolyard. The importance of the rising sun is combined with hands-on inquiry in which students explore the properties of shadows. Students (a) complete a modified Know and Need to Know (KNK) chart about shadows, (b) complete task cards to help direct their inquiry, (c) develop two rules about shadows and the sun, and (d) reflect upon the experience through a writing assignment.     

The effect of a 94 GHz electromagnetic field on neuronal microtubules

Hardware that generates electromagnetic waves with wavelengths from 1 to 10 mm (millimeter waves, “MMW”) is being used in a variety of applications, including high‐speed data communication and medical devices. This raises both practical and fundamental issues concerning the interaction of MMW electromagnetic fields (EMF) with biological tissues. A 94 GHz EMF is of particular interest because a number of applications, such as active denial systems, rely on this specific frequency. Most of the energy associated with MMW radiation is absorbed in the skin and, for a 94 GHz field, the power penetration depth is shallow (≈0.4 mm). At sufficiently high energies, skin heating is expected to activate thermal pain receptors, leading to the perception of pain. In addition to this “thermal” mechanism of action, a number of “non‐thermal” effects of MMW fields have been previously reported. Here, we investigated the influence of a 94 GHz EMF on the assembly/disassembly of neuronal microtubules in Xenopus spinal cord neurons. We reasoned that since microtubule array is regulated by a large number of intracellular signaling cascades, it may serve as an exquisitely sensitive reporter for the biochemical status of neuronal cytoplasm. We found that exposure to 94 GHz radiation increases the rate of microtubule assembly and that this effect can be entirely accounted for by the rapid EMF‐elicited temperature jump. Our data are consistent with the notion that the cellular effects of a 94 GHz EMF are mediated entirely by cell heating. Bioelectromagnetics 34:133–144, 2013. © 2012 Wiley Periodicals, Inc.     

Involuntary human hand movements due to FM radio waves in a moving van

Finland TRACT Involuntary movements of hands in a moving van on a public road were studied to clarify the possible role of frequency modulated radio waves on driving. The signals were measured in a direct 2 km test segment of an international road during repeated drives to both directions. Test subjects (n=4) had an ability to sense radio frequency field intensity variations of the environment. They were sitting in a minivan with arm movement detectors in their hands. A potentiometer was used to register the hand movements to a computer which simultaneously collected data on the amplitude of the RF signal of the local FM tower 30 km distance at a frequency of about 100 MHz. Involuntary hand movements of the test subjects correlated with electromagnetic field, i.e. FM radio wave intensity measured. They reacted also on the place of a geomagnetic anomaly crossing the road, which was found on the basis of these recordings and confirmed by the public geological maps of the area.In conclusion, RF irradiation seems to affect the human hand reflexes of sensitive persons in a moving van along a normal public road which may have significance in traffic safety.     

Generation of terahertz radiation in the reflection of a laser pulse from a dense plasma

The generation of low-frequency (terahertz) electromagnetic radiation in the reflection of a laser pulse from the boundary of a dense plasma is considered. Low-frequency wave electromagnetic fields in vacuum are excited by a vortex electric current that is induced at the plasma boundary by the ponderomotive force of the laser pulse. The spectral, angular, and energy parameters of the low-frequency radiation, as well as the spatiotemporal structure of the emitted waves, are investigated. It is shown that for typical parameters of present-day laser plasma experiments, the power of terahertz radiation can amount to tens of megawatts.