Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitchesA 2020 study captured structural changes in supercooled liquid water from 135 to 245 kelvin, finding reversible, reproducible evidence consistent with a temperature-dependent mixture of two liquid structures. The result helps explain why water behaves unusually, but it does not prove that water has a liquid–liquid critical point at atmospheric pressure.
Why is water considered unusual?
Water has a set of physical properties that differ from the patterns expected for many other liquids. Models proposed to explain these anomalies suggest that liquid water may contain two kinds of local structure, with their relative proportions changing with temperature. The study by Loni Kringle and colleagues tested for structural changes consistent with that picture; it did not claim to explain every unusual property of water.
As an Amazon Associate I earn from qualifying purchases.
What did the supercooled-water study measure?
Supercooled water is liquid water cooled below its usual freezing point without crystallizing. It is difficult to study because it can crystallize rapidly in the temperature range of interest. Kringle, Wyatt A. Thornley, Bruce D. Kay, and Greg A. Kimmel used nanosecond laser pulses to heat thin water films briefly, then rapidly cooled them. Infrared spectroscopy tracked the water’s structure during these short-lived states.
The paper, “Reversible structural transformations in supercooled liquid water from 135 to 245 K,” was published in Science in 2020. Its abstract describes measurements across 135–245 K. Read the paper abstract in Science; the Pacific Northwest National Laboratory publication record also summarizes the study.
#1 Best Overall
- 95+ YEARS OF EXPERIENCE - Carolina Biological has over 95 years of experience in providing high-quality science education materials, trusted by educators worldwide. As a leader in the field, they are committed to advancing hands-on learning, offering a vast range of biological specimens, lab equipment, and instructional materials. Carolina’s dedication to innovation, quality, and ethical sourcing has made them a go-to resource for schools, colleges, and independent learners.
- ENGAGING LEARNING TOOL – Allows students to visualize and feel molecular forces, reinforcing fundamental chemistry concepts through interactive experimentation.
- COMPLETE CLASS SET – Includes 6 Magnetic Water Kits, each with water, sodium, chloride, hydroxyl, and ethane molecules, plus a convenient carrying tray.
- COVERS KEY CONCEPTS – Ideal for teaching grades 8–12, this kit explores polarity, surface tension, solubility, states of matter, and crystal structure in a hands-on way.
- INTERACTIVE MOLECULAR MODELING – Powerful magnets in each molecule simulate polarity, hydrogen bonding, and attraction/repulsion, helping students grasp molecular interactions easily.
What changed as the water cooled?
The infrared measurements showed structural changes consistent with a mixture of two motifs, commonly described as high-temperature-like and low-temperature-like liquid structures. The fraction associated with the high-temperature motif declined rapidly as temperature fell from 245 K to 190 K. This trend is consistent with two-state mixture models, in which the balance between the two structural motifs shifts with temperature.
The authors also reported that the structural changes were reversible and reproducible. Loni Kringle, a postdoctoral researcher and study co-author, said: “A key observation is that all of the structural changes were reversible and reproducible,” PNNL’s announcement of the study explains the result for a general audience.
Rank #2
![[239 PCS] Organic Chemistry Model Kit | Molecular Model Kit for Students](https://m.media-amazon.com/images/I/511A7UN+wEL._SL160_.jpg)
- 𝐇𝐀𝐍𝐃𝐒-𝐎𝐍 𝐂𝐇𝐄𝐌𝐈𝐒𝐓𝐑𝐘 𝐋𝐄𝐀𝐑𝐍𝐈𝐍𝐆: Take chemistry beyond memorizing formulas with an interactive learning experience students can physically handle. Manipulating the pieces of this molecule kit gives learners a more engaging way to practice identifying atoms, connecting bonds, and studying molecular structures.
- 𝐓𝐔𝐑𝐍 𝟐𝐃 𝐃𝐈𝐀𝐆𝐑𝐀𝐌𝐒 𝐈𝐍𝐓𝐎 𝟑𝐃 𝐌𝐎𝐃𝐄𝐋𝐒: Make textbook structures easier to interpret by transforming flat molecular diagrams into physical 3D models. With the help of this chemistry modeling kit students can see the position of atoms and bonds from different angles, helping them better understand molecular shape and arrangement.
- 𝐁𝐔𝐈𝐋𝐃, 𝐄𝐗𝐏𝐋𝐎𝐑𝐄 & 𝐑𝐄𝐁𝐔𝐈𝐋𝐃: Encourage active discovery by letting students construct a structure, adjust its arrangement, and build it again for continued practice. The reusable pieces make it easy to explore different molecular configurations without needing a new model for every lesson.
- 𝐄𝐅𝐅𝐎𝐑𝐓𝐋𝐄𝐒𝐒 𝐀𝐒𝐒𝐄𝐌𝐁𝐋𝐘: Designed for smooth, straightforward model building, the pieces connect easily so students can spend less time figuring out how to assemble the kit and more time exploring chemistry. Simple construction also makes it convenient for repeated classroom or study use.
- 𝐆𝐈𝐕𝐄 𝐓𝐇𝐄 𝐆𝐈𝐅𝐓 𝐎𝐅 𝐃𝐈𝐒𝐂𝐎𝐕𝐄𝐑𝐘: Bring a creative twist to science gifting with this organic chemistry molecular model kit made for curious students, chemistry fans, and STEM enthusiasts. Whether for a birthday, classroom reward, holiday, or special occasion, it gives recipients something interesting to build, examine, and enjoy.
Can water exist as two liquids?
The experiment supports a model in which liquid water’s structure reflects a temperature-dependent mixture of two motifs. That is not the same as showing that two distinct liquid phases coexist under ordinary conditions. The paper says the measurements are consistent with two-state mixture models in the supercritical regime.
Nor did the experiment directly measure water density. It therefore does not establish a liquid–liquid critical point at atmospheric pressure. Chemistry World’s article frames the findings as clues to water’s unusual behavior, rather than a final resolution of the question: its coverage of the study discusses that interpretation.
Quick Recap
Best Value
- Visualize Chemical Concepts: Assemble parts to form complete molecules for easy understanding of molecular structure
- Supports Ball-and-Stick Model ＆Space-Filling Model: Modeling needs based on instructional needs,Easily understand the spatial relationships between molecules
- Install with Confidence: Recessed design for easy installation and removal. Robust atoms and resilient links ensure a long product life.
- Easy to Carry: Safety lock design,Organize by compartment.Easy to carry between home, school, lab, exam room
- Comprehensive content:Set contains 61 Atoms＆62 Links.Essential set for in-depth study of molecular modeling in organic ＆ inorganic chemistry.
Rank #4
- FOR BASIC TEACHING TO ADVANCED SCIENCE: 444 pieces molecular model kit, including 136 atoms, 158 bonds and 150 parts for Carbon-60(Fullerene), provides to students from Grade 7 to Graduate level.
- TWO CHEMICAL STRUCTURE MODELS: The ball-and-stick models use spheres to represent atoms and sticks to represent chemical bonds. In the space-filling model, the spheres are drawn to scale and are next to one another as atoms are in real molecules.
- CHEMISTRY EDUCATIONAL MOLECULE MODEL IN 3D: It can display chemical structure, molecular bond, and bond angle in all directions. Demonstrate fundamental molecular geometry, chemical molecular structure, stereochemistry with 3D modeling studies.
- EASY TO LEARN: The universal standard adopted for each atom's color makes it easier for you to use and learn. Atoms and chemical bonds combine tightly and firmly and can be easily disassembled by disconnecting tools.
- If you’re not in love with it for whatever reason, we’ll give you a full replacement or refund—no questions asked. If you have any doubt, please tell us. With nothing to worry about, or even to share with your friends, try it now.
Rank #3
- INCLUDED || 62 White Hydrogen balls, 31 Red Oxygen balls, 44 Gray links, 62 White links
- COLOR CODED || Elements identified by color
- HANDS-ON MODEL || Assembly required
- GREAT FOR SCIENCE CLASSROOMS || A clean and effective tool for teachers, or a project and study-aid for students
- Choking Hazard*
What the evidence does—and does not—show
- Direct measurement: Infrared spectroscopy tracked structural changes in briefly heated, rapidly cooled thin films of supercooled water.
- Repeatability: The transformations were reported as reversible and reproducible.
- Supported interpretation: The measured changes are consistent with a temperature-dependent mixture of two structural motifs and with two-state mixture models.
- Not established: The study did not demonstrate an atmospheric-pressure liquid–liquid critical point or settle the full explanation for water’s anomalies.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
