What causes ice to stick together

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In summary, the conversation discusses the phenomenon of ice cubes sticking together in the freezer over time. Possible causes mentioned include moisture in the air filling the gaps between the ice cubes, temperature fluctuations in the freezer, and regelation. The group also suggests conducting experiments to determine the effects of factors such as frequency of door opening, temperature setting, and storage containers on the ice cubes sticking together. The conversation concludes with the idea of using this topic as a testable question for students.
  • #1
Pengwuino
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I think everyone sees this happen. You buy a pack of ice from the store, it's all nice and loose and easy to use and stays that way in the storage bin. You bring it home and if you don't use it, you put it in the freezer. For a couple of days the ice stays nice and detached and usable. However, as time goes on, the ice starts getting stuck together up to the point it all gets attached into one giant piece.

What causes this? I've been trying to figure it out but I'm clueless. The freezers are well below 0... maybe moisture in the air starts filling the gap between the ice cubes to bond them together?
 
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Pengwuino said:
... maybe moisture in the air starts filling the gap between the ice cubes to bond them together?

That's my guess. The amount of build-up you get in older freezers (perhaps before the "frost-free" systems were well-engineered) makes clear there is a substantial source of water vapor.

Or maybe it is regelation?

I know from earlier work that the temperature cycles above and below the temperature you set it at. The temperature will likely rise above 0 C when the door is opened, but I would think too little energy gets into cause significant melting.

A few tests comes to mind:
1) Does the effect correlate to how often or how long the door is opened?
2) Does it correlate to what the temperature is set at?
3) Does it happen more to ice at the more of the bag than at the top? (I'm thinking about regelation here).
4) Does it happen more if weights on put on top of the ice bag?
5) What are the effects storing the ice in a reasonably air tight container?

I think I see a great testable question in this for my students...
 

What causes ice to stick together?

The phenomenon of ice sticking together is known as cohesion. It occurs due to the strong intermolecular forces between water molecules, known as hydrogen bonding. These bonds are formed when the positive hydrogen atom in one water molecule is attracted to the negative oxygen atom in another water molecule.

Why does ice stick together more in colder temperatures?

Lower temperatures mean that there is less energy in the water molecules, causing them to move less and form stronger hydrogen bonds. This results in a more rigid and tightly packed ice structure, making it more likely for ice to stick together.

Can impurities affect the stickiness of ice?

Yes, impurities such as dirt, dust, or salt can disrupt the formation of hydrogen bonds and weaken the cohesion between ice crystals. This can make it more difficult for ice to stick together.

Is there a difference between how ice sticks together on a molecular level compared to how it appears visually?

Yes, on a molecular level, ice sticks together through the formation of hydrogen bonds between water molecules. However, visually, ice may appear to stick together due to the presence of tiny air bubbles or cracks that create a rough surface, allowing the ice to grip onto itself.

What role do external factors, such as wind or pressure, play in ice sticking together?

External factors can play a significant role in the stickiness of ice. For example, strong winds can cause movement and friction between ice crystals, breaking down the hydrogen bonds and leading to less cohesion. On the other hand, high pressure can compress and melt the surface of the ice, creating a thin layer of water that can act as a lubricant and reduce the stickiness of ice.

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