Latest news with #physics
Irish Times
3 days ago
- Science
- Irish Times
Leaving Cert physics: ‘Anyone hoping for a replay of past papers will be shocked'
Students in today's Leaving Cert higher level physics exam faced challenges such as 'wordy' questions and mathematical twists. Pat Doyle, physics teacher at the Institute of Education, said the paper required students to think beyond the modes of questions from previous years and 'really bring their understanding of physics to these questions'. 'Anyone hoping to have an autopiloted replay of the previous papers will be shocked,' he said. 'Perhaps the more novel elements of this paper will be most challenging for those who struggle with the subject as they would need to take on extra interpretative work in the pressurised environment of the exam.' READ MORE Mr Doyle said most questions on experiments in section A were traditional in their approach, question two had an 'original twist on the conservation of momentum'. 'Previous papers use the scenario of a moving object striking a stationary object while this year's exam re-contextualised to objects moved by a spring,' he said. 'This mimics the forces in a nuclear reaction in a clever way, but it will have thrown students who might have expected to autopilot through the opening pages of the exam.' In section B, question six is traditionally very popular as it is an assortment of short questions. Yet Mr Doyle said this year's class will have found themselves moving more slowly through this question as the scale of the questions has shifted. [ Classroom to College: your essential newsletter to the Leaving Cert and study options Opens in new window ] 'The questions were expressed in a longer manner that needed to be parsed out before they could get to the examined concepts,' he said. 'Even then, some of the concepts examined were atypical for this section, most notably the speed of a galaxy would not have been anticipated as a short question which, while a nice question, would require a great deal more work to get all the marks. 'This novelty was balanced with an array of much more conventional questions. Question seven on planets, question eight on light diffraction and question nine on photoelectric effect and x- rays all fell within expectations and examples from previous years,'Mr Doyle ' aid. Question 10 on heat and temperature reinjected some twists back into the exam, he said, as the style of question on definition of temperature would not have been seen by students reviewing any recent papers. 'Those who ensured that they focused on the syllabus as a key guiding tool will know the material, but if you were looking for a repeat of previous exams this would have been a surprise,' he said. For many, question eleven on electricity will already have been unpopular even before the exam started as the students are not often drawn to the topic. 'This question is unlikely to convert them or increase the popularity of the topic as it was quite tricky. What will have been appealing was question 12 on particle physics with a special appearance of Ireland's only Nobel Prize winner for physics, Ernest Walton,' he said. ErnestWalton was an Irish physicist and Nobel laureate for his work with John Cockcroft with "atom-smashing" experiments done at Cambridge University in the early 1930s. Photograph: Jack McManus Question 13 was a comprehension style question on electromagnetism. Mr Doyle said neither the topic nor the style tends to appeal to students, but for those who attempted it ill be pleased with a 'rather nice question behind the text'. Question 14 is a popular choice as it contains some internal choice, with sections that ranged from the traditional to the obscure. Mr Doyle said the second section involved a tricky mathematical twist that skirted the edges of the syllabus. 'The third option demanded students read it very carefully to ensure that they approached the calculations correctly. Thankfully the paper closes with something more traditional and so students will have had the chance to conclude their time with the paper on more familiar territory,' he said.
Time of India
4 days ago
- General
- Time of India
Two girls from Pune score 100 percentile in MHT-CET (PCB)
1 2 Pune: Two girls from the district scored 100 percentile in the physics, chemistry, biology (PCB) group of Maharashtra Common Entrance Test (MHT-CET), the results of which were announced on Tuesday. Of the 2.82 lakh students who appeared for MHT-CET in the PCB group from across the state this year, 14 scored a perfect 100 percentile. Last year, 17 of the 2.9 lakh students who appeared for the exam scored 100 percentile in the same group. MHT-CET is a prerequisite for admission to the state's first-year undergraduate pharmacy programmes. Shreya Yadav (17), a 100 percentlier from the district, said she was preparing for National Eligibility-cum-Entrance Test, which prepared her for MHT-CET as well. "Honestly, I have not yet checked my MHT-CET score because I won't be taking admission based on it. I prepared well for my HSC exams, and since the CET syllabus is based on the same syllabus, I didn't need to study anything extra. I have my eyes set on MBBS. I was hoping for AIIMS Delhi, but my NEET ranking is just 2,128. I am hoping to get into AIIMS Nagpur," she said. During breaks from studies, Shreya ensured that she didn't watch any serials for fear of getting hooked. "I studied at least 10 hours a day. So, instead of watching regular TV, I went back to cartoons I used to love as a child. Mr Bean is my stress buster. Other than that, I also cycle," said Shreya. Unlike many other students who give importance to coaching classes over college during Stds XI and XII, Shreya's father, Prasad Yadav, said he ensured Sneha gave equal importance to both. "We wanted her to be in a proper college and not a dummy. Hence, she was a regular student at Fergusson College. I think colleges prepare students better for senior college. In college, she had laboratory practicals, which will serve her well when she goes to senior college. Social skills are very important as you grow, and colleges teach you that," said Prasad, adding that she did yoga regularly. Siddhi Bade, from Baramati, who also scored 100 percentile from Pune district, has her hopes pinned on AIIMS Delhi. "All my life, I wanted to be a doctor. I was preparing for NEET since Std XI and secured 26th All-India rank this time. I never prepared differently for MHT-CET as the NEET syllabus covers everything," said Siddhi, whose parents are govt schoolteachers. Her elder brother is an engineering student. Another student, Snehal Diwate from Pune, who secured 99.97 percentile, topped in the ST category. The State CET cell is yet to release its schedule for the centralized admission process. With the Pharmacy Council of India (PCI) extending the deadline for approval till Sept 30, representatives of colleges offering pharmacy education in the state fear yet another delay in the admission process. This year, the examination was conducted from April 9 to 17 at 172 centres within Maharashtra, and 9 examination centres outside the state.
Yahoo
7 days ago
- Science
- Yahoo
Scientists create world's tiniest violin —and it's only visible with a microscope
British physicists claim they've created the 'world's smallest violin' — and, by the looks of it, they could take a bow for their masterpiece invention. The brainy bunch at Loughborough University used nanotechnology to build the teeny instrument, which is no bigger than a speck of dust and can only be seen with a microscope. Made of platinum, the mini-instrument measures 35 microns, one-millionth of a meter long, and 13 microns wide. Loughborough explained on its website that it's tiny enough to fit within the width of a human's hair. The scientists created the violin, which is just a microscopic image and isn't playable, as a test of the school's new nanolithography system, which allows them to build and study structures at the nanoscale. The project references the expression 'Can you hear the world's smallest violin playing just for you?' which pokes fun at people being overly dramatic. 'Though creating the world's smallest violin may seem like fun and games, a lot of what we've learned in the process has actually laid the groundwork for the research we're now undertaking,' Kelly Morrison, professor of experimental physics at the university, said on its website. 'Our nanolithography system allows us to design experiments that probe materials in different ways – using light, magnetism, or electricity – and observe their responses. Once we understand how materials behave, we can start applying that knowledge to develop new technologies.' The violin was made by a NanoFrazor, a nano-sculpting machine that uses a technique where a heated, needle-like tip writes patterns. First, a chip was coated with a gel-like material and then placed under the machine, effectively burning the violin pattern into the surface. After the pattern was etched, the underlayer of the gel dissolved, and a violin-shaped hole remained. A thin layer of platinum was then inserted into the chip, which was then rinsed with acetone to remove any remaining particles. The prototype took three hours to create. However, the team's final version took several months. 'Depending on how you engage with technology, there are people who are always looking to have something that runs faster, better, more efficient,' Morrison said in a YouTube video. 'That requires … finding a way to scale down.'
WIRED
13-06-2025
- Science
- WIRED
Are Those Viral ‘Cooling Blankets' for Real?
Jun 13, 2025 7:00 AM According to physics, any blanket can cool you—for a few minutes. But a real cooling blanket is possible with phase-change materials. Photograph:If you spend much time on the internet, you will see the same things pop up again and again. For me, it's these 'cooling blankets' that people talk about on social media. I mean, it sounds great for summer—just like a blanket that warms you up but in reverse. Sadly, these products don't do what they claim. They might be breathable so they don't make you as hot as an ordinary blanket would, but you'd still be cooler with no blanket at all. However, there is hope. Someone has created a real cooling blanket that's sort of awesome. Of course, there's a bunch of physics here, so let's get to it. Temperature vs. Energy Temperature is one of those words everyone uses and no one understands. In chemistry it's the average kinetic energy, or vibrational motion, of the molecules in a substance. The greater the commotion, the higher the temperature. But I like this more pragmatic definition: Temperature is the property two objects will have in common when they're in contact for a long time. So, if you take a hot block of metal and set it against a cold block of metal, eventually they will have the same temperature. Heat flows from the warmer thing to the cooler thing until they equalize. (Note: It doesn't work the other way around; you can't transfer 'coolness.') We also talk about objects having a certain amount of thermal energy , which you'd get by adding up the kinetic energy of all the particles inside it. It depends on three things: the mass of the object, its temperature, and the material it's made of. So for instance, focusing on mass, big potatoes have more thermal energy than small potatoes at the same temperature. Now, if you look at the type of material, every substance has a 'specific heat capacity,' which is the amount of heat required to raise the temperature of that substance by one degree. Try this at home. Find two objects that have been sitting in your room for a while, so they're both at room temperature. Here, I have a block of wood and a block of aluminum. Touch both objects. They're the same temperature, but the wood feels warmer, right? Why is that? It's not about temperature but thermal energy. When your hand touches an object, there is a heat conduction interaction. Energy is transferred from your warmer hand to the cooler object until the two are the same temperature. However, with the metal block it takes way more energy to reach the temperature of your hand. It feels cooler because it causes your hand to lose more energy. You'll notice the same thing when you go swimming. An air temperature of 75°F feels nice and comfortable, but wading into water of the same temperature feels really cold. That's because water has a much higher mass and specific heat capacity than air, which causes you to lose more thermal energy and feel colder. All Blankets Cool So, blankets, how do they work? A blanket is basically an insulator. That means it prevents energy transfer between objects at different temperatures. Wrapping yourself in a blanket on a cold day keeps you from losing body heat to the air around you, so you feel warmer. Similarly, if you put a blanket around a cold soda on a warm day, it will slow down the transfer of thermal energy from the air to the soda, keeping the soda cold longer. But what if you feel hot and you put on a blanket? In that case, two things can happen at once. It can still act as a thermal insulator and slow down the transfer of energy between you and the air. Unless the ambient air is above 98.5°F, this is going to make you hotter, not cooler. However, the blanket can also have a thermal interaction with your body. Suppose you have a 80°F blanket in contact with a 98°F person. This will raise the temperature of the blanket while reducing the thermal energy of your body. Yes, it will act as a cooling blanket—at least for a few minutes, until the temperatures are equalized. So, what makes one blanket cool more effectively than another? First, it should have a high mass, so that it takes a lot of energy to warm up. Second, the blanket needs to make good contact with your skin to increase the thermal interaction. So, one of those light fluffy blankets won't cool you off that much. Other than that, it's just a normal blanket. But I'm a sucker for trying these things, so I bought a cheap 'cooling blanket' online. (I know, someone will say it doesn't work unless you get an expensive one.) For those who say their cooling blanket was out in the sun and they measured a 75°F temperature, I don't believe you. Check this out. I have three blankets on my sofa. One of them is the cooling blanket and the others are normal. In back is the same picture taken with an infrared camera so that different colors represent different temperatures. Can you tell which one is the cooling blanket? Nope. You can't. There's almost no difference in the temperatures. They are all cooling blankets. They are also all normal blankets. A Real Cooling Blanket But what if I told you it's possible to have a thermal interaction between two objects but one of them doesn't change in temperature. Yes, this is a thing—it's called a phase transition. It happens whenever a material changes from solid to liquid or liquid to gas. Here's an interesting experiment. Imagine I take a beaker with frozen water (aka ice) that's colder than the freezing point (maybe –10°C). Then I put the beaker on a hot plate and add energy to it, measuring the temperature of the water as I go. Here is what that would look like: As you can see, the ice increases in temperature until it reaches the melting point, 0°C (32°F). At that point the temperature levels off, and it remains constant until all the ice melts—even though heat is still being added to the system. Why is that? It's because the energy is being used to break the molecular bonds and turn the solid into a liquid. Once it's entirely liquid, the temperature starts rising again, until it reaches the boiling point (100°C). Again, the temperature levels off until all the water turns to gas. (This is why it's nice to cook with boiling water—it stays the same temperature.) You can see how this would make for a better cooling blanket. Because of these temperature plateaus during a phase change, you can keep transferring thermal energy from your body to the blanket without the blanket getting warmer and becoming ineffective. Does this mean you could use an ice blanket, maybe with the water in a flexible lining, to cool yourself? Sure. But it would be excruciating and you might get frostbite. Also, once you melt the ice and heat up the water, you'd need to put your blanket back in the freezer before you could use it again. But how about a material that has a melting point closer to the temperature of the human body? In this video from the YouTube channel NighthawkInLight, Ben Cusick makes just such a phase-change material (PCM) from common salts (sodium sulfate and sodium chloride). Of course I had to try making some of this stuff myself. I'm not a chemist, but I think it turned out pretty well. It depends on your mixture and the type of salts used, but these kinds of materials have a melting point somewhere around 18°C (65°F). Why does that matter? Well, first, it's not so cold that it hurts. Second, you don't need a freezer; a cool place like a basement floor will make it refreeze. And best of all, the high melting point means it will melt slowly at room temperature, so the phase transition lasts a long time—hours instead of minutes—and it will cool you off during this whole time. Put this stuff in the lining of a blanket and voilà! Pretty cool, right?
Arab News
12-06-2025
- Science
- Arab News
Book Review: ‘Brief Answers to the Big Questions'
Stephen Hawking's 'Brief Answers to the Big Questions' is a fascinating and thought-provoking exploration of science's most profound mysteries, offering insights into the origins of the universe and humanity's place within it. Published in 2018, this final work by the renowned physicist combines complex scientific ideas with accessible explanations, making it a must-read for anyone curious about the cosmos. Hawking begins by addressing how the universe came into existence. He explains that the laws of physics are sufficient to describe the universe's origins, suggesting that it could arise from a state of nothingness due to the balance of positive and negative energy. By linking this to the nature of time, which began alongside the universe itself, he offers a perspective grounded in scientific reasoning. The book also delves into the evolution of the universe and the evidence supporting it. Hawking discusses how the redshift of light from distant galaxies confirms the universe's expansion, while the cosmic microwave background radiation provides a glimpse into its dense, hot beginnings. Through the anthropic principle, he demonstrates how the unique conditions of our universe make life possible, underscoring how rare such conditions are. Hawking also considers the possibility of extraterrestrial life, suggesting that while life may exist elsewhere, intelligent civilizations are unlikely to be nearby or at the same stage of development. He cautions against attempts to communicate with alien life, warning that such interactions could pose risks to humanity. One of the book's most intriguing sections explores black holes. Hawking examines their immense density, the singularity at their core, and the paradox of information loss. He explains how black holes might release information as they evaporate, preserving the fundamental laws of physics. Beyond its scientific insights, the book is a call to action. Hawking urges readers to prioritize scientific progress, safeguard the planet, and prepare for the challenges of the future. Though some sections may challenge non-experts, 'Brief Answers to the Big Questions' remains accessible, inspiring, and deeply insightful — a fitting conclusion to Hawking's extraordinary legacy.
