- Moisture is water in liquid form
- There is moisture on the surface of the airplane
- Therefore, there is water on the surface of the airplane

- An airplane is climbing in the sky
- Climbing increases altitude
- Therefore, the airplane is increasing in altitude

- The airplane is increasing in altitude
- As altitude increases , the temperature of the air will decrease in the troposphere
- Therefore, the temperature of the air decreases when the altitude of the airplane increases

- There is water on the surface of the airplane
- The temperature of the air decreases when the altitude of the airplane increases
- Therefore, the water on the surface of the airplane will decrease in temperature

- The water on the surface of the airplane will decrease in temperature
- Water is a kind of substance
- Freezing means a substance changes from a liquid into a solid by decreasing heat energy
- Water is in the solid state , called ice
- So, the water on the surface of the airplane will freeze into ice

Therefore, the water on the surface of the airplane will freeze into ice
[Question]As an airplane climbs in the sky, the pilot notices ice crystals forming on the windshield. This happens because
[Context]- Moisture is water in liquid form 
- Water is a kind of substance 
- Freezing means a substance changes from a liquid into a solid by decreasing heat energy 
- There is moisture on the surface of the airplane 
- An airplane is climbing in the sky 
- Climbing increases altitude 
- As altitude increases , the temperature of the air will decrease in the troposphere 
- Water is in the solid state , called ice