Slider color? Making a thermometer?

Hello! I'm working on Cold War lesson plan for high school students. I would like for the kids to be able to slide a slider that I have placed on a thermometer in order to show the "temperature" for each Cold War event. Is there a way to do this or something similar or have an even better idea? I've included a screenshot to explain the general idea. 

 

Thank you in advance! 

3 Replies
Wendy Farmer