The work performed by the engine is therefore greater than the energy taken from the hotter medium alone — the efficiency is over percent. The achievement of the Munich physicists could additionally be interesting for cosmology, since the thermodynamic behaviour of negative temperature exhibits parallels to so-called dark energy.
Cosmologists postulate dark energy as the elusive force that accelerates the expansion of the universe, although the cosmos should in fact contract because of the gravitational attraction between all masses. There is a similar phenomenon in the atomic cloud in the Munich laboratory: the experiment relies upon the fact that the atoms in the gas do not repel each other as in a usual gas, but instead interact attractively. This means that the atoms exert a negative instead of a positive pressure.
As a consequence, the atom cloud wants to contract and should really collapse — just as would be expected for the universe under the effect of gravity. But because of its negative temperature this does not happen. The gas is saved from collapse just like the universe.
The extremely precise control of nuclear excitations opens up possibilities of ultra-precise atomic clocks and powerful nuclear batteries. Many publications by Max Planck scientists in were of great social relevance or met with a great media response. We have selected 13 articles to present you with an overview of some noteworthy research of the year.
For the first time, it is possible to produce crystalline layers of precious metals that consist of a single atomic layer and which are semiconducting. A new form of spectroscopy provides insights for the development of resistance-free current transport at ambient temperature. Cell-sized droplets equipped with natural and synthetic parts are able to perform photosynthesis. In the future, they could serve as bioreactors for the sustainable, light driven fixation of CO 2 into value-added compounds.
Homepage Newsroom Research News A temperature below absolute zero. A temperature below absolute zero Atoms at negative absolute temperature are the hottest systems in the world. January 04, Energy Quantum Physics. Other Interesting Articles. Awards Quantum Physics. Climate Energy. A mathematical point has zero length.
Those zeroes might be unfamiliar, but they follow a consistent logic. All represent the absence of a certain quality: mass, electric charge, distance. We tend to think of hot and cold as relative things. A cup of hour-old tea, for example, is colder than the fire on your stove but hotter than an ice cube. Absolute zero represents the coldest possible temperature, which defies the this-versus-that pattern.
The key to decoding absolute zero is understanding what temperature is. Think of it as a game of atomic dodgeball. When the ball hits you, you feel its energy. Trillions and trillions of those dodgeball hits, happening on an invisibly small scale, are what we perceive as temperature. Fast-moving atoms hit hard, which we feel as a high temperature. In , researchers at MIT eclipsed this with a new record of pK 0. Related Stories.
But in the quantum world, which deals with the super small and the ultra-cold, determining how hot or cold something is starts to A figure and four Researchers set out to learn more about the everyday The formulas could be applied to further Some have observed that for a device on Earth facing space, the chilling outflow of energy from the device can be Succession on Mount St. Interdisciplinary Teach a class like forensic science where you have to apply physics, chemistry, and biology content?
View all Interdisciplinary. Most Popular Solution Preparation Guide This brief guide will provide you with the information you need to make a number of solutions commonly used in educational laboratories. Accuracy Versus Precision Beanbag Toss In this activity, students engage in a game of beanbag toss—but instead of merely keeping score, they explore statistical concepts such as mean, median, mode, and range. The Whys and Hows of Writing a Lab Report This author provides an excellent student lab-report format, explains how it adapts to different science disciplines, and suggests simple labs to familiarize students with it.
Lab Safety Information Keep your classroom or lab safe throughout the schoolyear with lots of helpful tips, hints, and safety techniques. View all Lab Safety Information. Product Support You have questions-we have answers. View all Product Support. Professional Growth Brush up on the latest instructional strategies and pedagogy with information from our teaching partners, instructional designers, and academic consultants. View all Professional Growth.
Classroom Activities on a Budget Feeling the pinch from the current economy? Ethanol and acetone are very flammable. Caution: Dry ice and liquid nitrogen should be handled very carefully wear safety glasses and insulated thermal gloves due to the risk of frostbite. Caution: Never put dry ice or liquid nitrogen in a closed container because each will build up pressure and explode the container.
Wear safety glasses during the experiment. Use insulated thermal gloves and appropriate care when handling the water baths, dry ice, liquid nitrogen, and Absolute Zero Demonstrator.
Procedure All participants put on safety glasses. Individuals responsible for handling the Absolute Zero Demonstrator apparatus, water baths, dry ice, and liquid nitrogen put on insulated thermal gloves. Support the apparatus with a large 3-prong clamp and clamp holder and support the thermometer with a small 3-prong clamp and clamp holder. Allow the water to return to a full boil. Wait a few minutes for the apparatus to equilibrate. The pressure reading should stabilize at a constant value.
Record the pressure to the nearest mm Hg and temperature to the nearest 0. Remove the apparatus from the bath. Support the apparatus and thermometer as described in step 2. Repeat steps 3 to 5. Support the apparatus as described in step 2. Do not use a thermometer to measure the temperature. The dry ice bath is assumed to be at the sublimation temperature of carbon dioxide, 1 atm pressure and — Record the pressure gauge reading and — Optional: Purge the apparatus with helium. The liquid nitrogen bath is assumed to be at its boiling point, 1 atm pressure and — Data analysis Prepare a graph of pressure vs.
Draw the best straight line through the data. Extend the line until it intersects the x -axis. If you have access to a graphing calculator or graphing software, graph the data and perform a linear regression analysis.
Record the slope, y -intercept, and correlation coefficient r. The closer the value of r is to 1. Data table Reading No. Show your calculations. Are pressure and temperature directly or inversely related? Justify your answer based on your graph. Discuss any sources of error that occurred or any improvements that could be made in this experiment.
Instructor's notes Caution: Do not use open flames during the experiment. Sample data: Reading No. Check the approximate amount of water needed to cover the bulb in the bath. Note: Be careful not to overfill the beakers or they will overflow when the bulb is immersed.
Different pairs of students can read the pressure and temperature values for each data point. An alcohol thermometer will freeze in liquid nitrogen.
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