a glass thermometer is made of colored alcohol in a tube & alcohol is a kind of liquid -> a plastic share is made of wires steam in a reaction a glass thermometer is made of alcohol liquid in a tube  a glass thermometer is made of alcohol liquid in a tube & as the steam in a thermometer expands , the width of the steam in that star will decrease -> if the alcohol liquid in the tube expands, then the height of the alcohol liquid will increase if the alcohol liquid in the tube expands, then the height of the alcohol liquid will increase  if the periods steam in the flows expands, then the width of the winter steam will decrease & if a material is heated , then the material will expand -> the height of the alcohol liquid changes because alcohol is heated