Chemical composition of a hailstone: evidence for tracking hailstone trajectory in deep convection

Change of State: Condensation, Sublimation, and DepositionMatter changes from one state to another when heat is added or removed. Condensation, sublimation, and deposition are three phase changes that occur due to variations in temperature and pressure.Condensation happens when a gas turns into a liquid, such as water vapor, forming dew.Sublimation occurs when a solid changes directly into a gas without becoming a liquid, like dry ice, which turns into carbon dioxide gas.Deposition is the...

CometsComets are icy objects that travel through space in long, elliptical orbits around the Sun. They are composed of ice, dust, and rock, earning them the nickname "dirty snowballs." When a comet approaches the Sun, its ice vaporizes, forming a bright, glowing tail. Scientists study comets because they contain materials from the early solar system, providing clues about how planets and other celestial bodies formed.Science and Engineering Practice (SEP): Analyzing and Interpreting...

Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.

MeteorsMeteors are pieces of rock or metal that travel through space. When they enter Earth's atmosphere, they heat up and create a bright streak of light in the sky. People often call them “shooting stars,” but they are not stars. Most meteors burn up before reaching the ground, but some survive and land on Earth. These are called meteorites. Scientists study meteors to learn more about space and the history of our solar system.Science and Engineering Practice (SEP): Developing and Using...

The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...

Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...