Fancy ice cubes

Boiling water causes the air that is trapped between the water molecules to come out of the water (by thermal agitation); as the impurities in water are what causes the ice to be white, if we remove the air this way, it should be clear.

After boiling the water ,water gets almost free from dissolved air,as solubility of gases decreases with temperature.which results in transparency of ice cube ,since there remains almost no impurity to make it opaque.

The ice become opaque because of air trapped in the water,which gets stuck when it freezes. So by boiling water will remove air stuck in water and.now when you will freeze water it will be transparent.

Rather than guess, I did the experiment. None of these make any real difference. You can see little bubbles in the ice made from carbonated water. But that's about it. See if you can tell the difference. There are 4 cubes of each from left to right. Which is which?

This doesn't actually work very well. A better solution is to boil it first, then put it in a cooler with the lid removed and freeze. This is because it will freeze only on one side (the exposed top), pushing any impurities in the water toward the bottom. Before it has a chance to freeze all the way through you remove the ice and discard the dirty water at the bottom. Clear ice. This process is similar to why frozen pond ice is clear. Just boiling it will give you clearer ice but not perfectly clear ice.

Boiling will help, but almost all clear ice in bars is manufactured using directional freezing: http://www.alcademics.com/2016/04/what-is-directional-freezing.html

Some of the idea I think for boiling water is that solubility of gasses in the air decreases as temperature increase (google solubility of gasses vs temperature) so therefore gasses are released from the water that is to become ice. However this doesn’t apply to dissolved impurities such as salt. As water freezes the salts or other dissolved impurities will be slowly “pushed” out and they form what looks like a “cloud” within the centre of the ice cube, which is usually the last part to freeze. This is called brine rejection (https://en.m.wikipedia.org/wiki/Brine_rejection). In the Wikipedia case the salt sinks, in our ice cube case it and other impurities get “pushed” to the centre as the water freezes. As another writer wrote, directional freezing can move this cloudy part to, for example, the bottom part of the ice and make the top clear. Include only the top and we get clear ice from a machine or lake!

So boiling water may make it clearer, but if you have lots impurities in your water that are not dissolved gasses, you will still get “cloudy “ ice.

Clear ice refers to a solid precipitation which forms when air temperature is between $\text{0 °C (32 °F)}$ and there are supercooled, relatively large drops of water $\text{(from freezing fog)}$ . A rapid accretion and a slow dissipation of latent heat of fusion favor the formation of a transparent ice coating, without air or other impurities.

A similar phenomenon occurs when freezing rain or drizzle hit a surface and is called glaze.

Clear ice, when formed on the ground, is often called black ice, and can be extremely hazardous.

Clear ice is denser and more homogeneous than hard rime; like rime, however, clear ice accumulates on branches and overhead lines, where it is particularly dangerous due to its relative high density.

As there is dissolved air in normal water so when we freeze it this forms a translucent or whitish ICS cube After heating or boiling air gets out of water so when we heat it forms a transparent ice

Hot water releases more carbon dioxide that had been saved inside the water to the air, causing less carbon dioxide to be inside the water. Hence, the ice cubes are clearer

$\boxed {Boiled water}$