Take some baking soda and vinegar . Mix them and let it rest for about an hour . Add water to it and then wait for some time . Now put this mixture on a flame and let it heat till it becomes transparent . Pour it out in a glass and let it become cool . Take a stick , scrape of a little solid part of the mixture from the vessel in which it had boiled . Put this in the glass . You ’ ll see a beautiful ice pattern forming in it and that too at room temperature . You have hot ice !