Please choose the correct answer to the question: Colored alcohol is used in some glass thermometers. When placed in air of different temperatures, the column of alcohol rises or falls in the glass thermometer. Which of the following best explains why the height of the alcohol column changes?

Answer1: The glass contracts when heated. Answer2: The alcohol contracts when heated. Answer3: The glass expands more than the alcohol when heated. Answer4: The alcohol expands more than the glass when heated.

Answer format: answer1/answer2/answer3/answer4
Answer: answer4