Krampf points out that, “Because we’re using fire, always be sure you keep safety in mind, and be sure you’ve got an adult around, so that you’ll have somebody to blame if something goes wrong!”

So, what is it about water that makes it absorb the heat from the candle flame so fast and so protect the rubber of the balloon from melting or burning? Water has the second highest specific heat capacity of any known chemical compound, after ammonia. This is due to the extensive but transient network of temporary hydrogen bonds that form between the oxygen atom at the centre of each water molecule and a hydrogen atom from a neighbouring water molecule. This fluxional network of loose bonds allows liquid water to rapidly absorb heat and also allows the heat to quickly be dispersed through the bulk liquid.

WARNING: Please don’t attempt this experiment with anything but water in the balloon. Water is about the only fluid that is safe to use but more to the point, it won’t work properly with any other fluid.

Save a balloon with water is a post from: Sciencebase Science Blog

But, first check out this great science project you can download now that includes A Pinch of Salt which will help you answer that question.

The fact that dissolving a salt in a liquid, such as water, affects its boiling point comes under the general heading of colligative properties in chemistry. In fact, it’s a generic phenomenon dissolve one substance (the solute) in another (the solvent) and you will raise its boiling point.

Colligative properties determine how a solvent will behave once it becomes a solution, as it were. The degree of change depends on the amount of solute dissolved in the bulk liquid, not the type of solute.

So, here’s a rough explanation of what’s going on. If a substance has a lower vapour pressure than the liquid (it’s relatively non-volatile in other words) then dissolving that substance in the liquid, common salt (NaCl) in water (H₂O), for instance, will lower the overall vapour pressure of the resulting solution compared with the pure liquid. A lower vapour pressure means that the solution has to be heated more than the pure liquid to make its molecules vaporise. It is an effect of the dilution of the solvent in the presence of a solute.

Put another way, if a solute is dissolved in a solvent, then the number of solvent molecules at the surface of the solution is less than for pure solvent. The surface molecules can thus be considered “diluted” by the less volatile particles of solute. The rate of exchange between solvent in the solution and in the air above the solution is lower (vapour pressure of the solvent is reduced). A lower vapour pressure means that a higher temperature is necessary to boil the water in the solution, hence boiling-point elevation.

Conversely, adding common salt to water will lower its freezing point. This effect is exploited in cold weather when adding grit (rock salt) to the roads. The salt dissolves in the water condensing on the road surface and lowers its freezing point so that the temperature has to fall that bit more before ice will form on the roads.

A much more fun use for freezing point depression is to add salt to ice to make icecream. The About site has some instructions on how to do this, although it’s probably not too tasty.

Curiously, at least one Sciencebase reader was searching for the phrase “how does sugar affect the boiling point of water?” and landed on this page. This is essentially the same question as does salt affect the boiling point of water. The nature of the solute, the material being dissolved in the solvent, is pretty much irrelevant at a first estimate. Rather it is the amount of material that is dissolved (which depends on the materials solubility) that influences the boiling and freezing points as described above.

Salt and the Boiling Point of Water is a post from: Sciencebase Science Blog

The long answer follows:

Jon Nelson, a researcher with Ritsumeikan University in Japan, has studied snowflakes for fifteen years, and has some interesting insights into their delicate structures. He points out that the old adage that ‘no two snowflakes are alike’ might be true for larger snowflakes, but it does not hold true for smaller, simpler crystals that fall before they’ve had a chance to fully develop into the familiarly evocative hexagonal flakes.

Regardless, the shape of snow crystals are incredibly diverse, this is partly due to their sensitivity to even the smallest temperature change as they fall through the clouds.

So, how do snowflakes form in the first place?

Put simply, at the heart of every snowflake is a minute grain of dust that was once floating in a cloud. Water vapor from the atmosphere condenses on this dust grain forming a droplet that freezes instantly (it’s a nucleation process if you want it technical).

The ice crystals grow hexagonally as is the wont of frozen water. The shape originates from the chemistry of the water molecule, which consists of two hydrogen atoms bonded to an oxygen atom, H-O-H. These atoms are not in a straight line though, they’re at an angle and this angle means that when severl water molecules get hitched together through hydrogen-bonding in the frozen state the simplest way to do that (i.e. the lowest energy arrangement) results in six-sided symmetry, hence six-side flakes.

The flake eventually sprouts six tiny branches. Each of these branches grows to form side branches in a direction and shape that are influenced by the clustering of water molecules on the ice crystal surfaces.

The American Chemical Society has produced an excellent poster illustrating all this. You can download it as a PDF file here.

You may be wondering why scientists are so interested in snowflakes, after all in many parts of the world, you’re never going to get a chance to test your theories.

Well, snowflakes and ice crystals have an effect on the global climate because of the reflectivity, they are thought to help catalyze the break of ozone in the upper atmosphere depletion, and they also play a critical role in the build up electric charges in clouds that leads to lightning.

The Scout Report recently highlighted another researcher with an interest in ice crystal growth and pattern formation in ice. Kenneth Libbrecht at Caltech University, the Report says, is “so interested in fact, he went
ahead and created this lovely website that documents the very wide, and very
interesting world, of “snowflakes, snow crystals, and other ice phenomena.”

But, that’s probably enough science for today. So, wherever you are let it snow, let it snow, let it snow…and compliments of the season from Sciencebase.com

Are all snowflakes different is a post from: Sciencebase Science Blog

The latest Reactive Profile is in Issue 60 of our chemistry magazine.

Synthesizing a new breed of chemist is a post from: Sciencebase Science Blog

As ever, sciencebase is here to help with a bench covered in science fair projects, a labful of science experiments and all the science books for home study you can bear.

A word of warning, please DO NOT try to light your last barbecue of the summer with liquid oxygen…

Science fair projects and experiments is a post from: Sciencebase Science Blog

A friend of mine is into nature conservation in a big way and one of the tools of the trade, which to the outsider may seem rather odd, is owl pellet dissection.

Owl pellets are the regurgitates remains (bones, feathers and other indigestibles) that accumulate in this bird of prey’s gizzard after it dines on small rodents and other critters. The dessicated pellets are to be found lying where they are discarded by the owl and can provide important information about what critters are being preyed on in owl territory.

The only way to get at that information, however, is to tease apart the pellet with tweezers and other implements to extract the bones from the tangle of hair and other detritus. It needs a steady hand, a keen eye, and a lot of patience. What you will find within is quite amazing though, tiny jaw bones and skulls, femurs, tibias pelvic bones and more.

Identifying which bone belongs to which creature takes even more patience, but it is possible and provides useful insights into the prevalence or otherwise of particular small mammals in a given area where owls prey.

For more on owl pellet dissection, check out this site http://www.kidwings.com/owlpellets/.

The reason I bring it up (pardon the pun) today, is that owl pellet dissection was the hot new search phrase on the sciencebase site this last month, with dozens of visitors all flapping for information on the subject. It’s not a topic that’s been searched for here before, so I thought I’d provide some background in case we have another flutter of en-raptor-ed activity.

Owl pellet dissection is a post from: Sciencebase Science Blog

We’ve got a stack of information available to science students including science homework and chemistry assignment help, science fair projects and science class demonstration guides. The free stuff is fine, but we also offer science project resources in partnership with 24 Hour Science Projects, which you or your parent will have to pay for. We recommend these project packs very highly though as they’re almost guaranteed to help you make the grade in science class as well as improve your understanding of some important scientific principles.

The following pages in the Sciencebase archives will help you find the science project inspiration you need:

• Science demonstration projects
• Science homework help
• Sience projects
• Scince fair projects online
• Useful scientific and computing tools
• Simple sience experiments
• Chemistry assignment help
• Winning science fair experiments
• Science lab projects
• Science fair projects
• Science fair project ideas
• Intel science fair prize

Apologies for those typos in some of the file names, they can’t be corrected now, but rest assured we do know how to spell science

Science Projects Demonstrations Guides Ideas is a post from: Sciencebase Science Blog

You can download individual project packs (24-hour or weekend) right now, but I’ve negotiated a limited time offer for Sciencebase visitors that isn’t mentioned on the company’s site so that you can get all ten project guides at a discount. Click here to start downloading your science fair project guides.

Science Fair Project Guides – Bonus is a post from: Sciencebase Science Blog

Education News is a post from: Sciencebase Science Blog

The pole has moved hundreds of kilometres in the last couple of centuries and could reach Siberia within another fifty years according to Oregon State University paleomagnetist Joseph Stoner speaking at the annual meeting of the American Geophysical Union in San Francisco, California, this week. The remarkably rapid (for geological change) movement of the magnetic pole doesn’t necessarily mean that our planet is going through a large-scale change that would result in the reversal of the Earth’s magnetic field as some people fear. Instead, this may be part of a normal oscillation, says Stoner, and could swing back towards Canada again.

Whichever way it goes, check out the sciencebase magnetic science lesson plan courtesy of Oregon’s Columbia Education Center.

Science Lesson Plan on Magnetism is a post from: Sciencebase Science Blog