a block of ice is placed on a hot sidewalk & if something is placed on something else then that something is touching that something else ->  a block of ice is touching a hot sidewalk  ice is a kind of object & ice is cold in temperature ->  ice is a kind of cold object  a block of ice is touching a hot sidewalk & ice is a kind of cold object & the sidewalk is a kind of object ->  a block of ice on a hot sidewalk is an example of cold object touching warmer object  thermal conduction is when heat flows from warmer object to cooler object & when a cooler object touches a warmer object , thermal conduction occurs ->  when a cooler object touches a warmer object, heat will flow from the warmer object to the cooler object  a block of ice on a hot sidewalk is an example of cold object touching warmer object & when a cooler object touches a warmer object, heat will flow from the warmer object to the cooler object ->  heat will flow from the hot sidewalk to the block of ice  heat will flow from the hot sidewalk to the block of ice & if heat is flow to a substance, then the heat energy in that substance will increase ->  the hot sidewalk increase the heat energy in the block of ice  the hot sidewalk increase the heat energy in the block of ice & melting means substance changes from a solid into a liquid by increasing heat energy -> the block of ice will melt