sentence: Some extra chemicals are used to change the way the fuel feels and acts.
sentences_before: Extra chemicals are often added to rocket candy. They are used to change the way the fuel burns. These extra chemicals can make the rocket candy burn faster or slower. Some are used to change the color of the flame. Other chemicals are used to make smoke when the rocket flies.
sentences_after: They can make the fuel less likely to break. They can also make the fuel more like a flowing liquid. This can make it easier  to put the rocket candy into the motor.
concept_name: extra chemical
headings: Rocket candy Components Extra chemicals
categories: Fuel Rockets