A) It is less dense than cooler air. B) It is heavier than cool air. C) It expands in size. D) It has more pressure.
A) It escapes. B) It becomes heavier. C) It contracts. D) It expands.
A) The burner. B) The envelope. C) The flame. D) The basket.
A) 5 to 10 hours. B) 1 to 2 hours. C) 30 minutes. D) All day.
A) To stabilize the balloon. B) To increase lift. C) To release hot air. D) To let in cool air.
A) High humidity. B) Calm and clear weather. C) Windy and cloudy weather. D) Rainy conditions.
A) By adding more gas. B) By changing the balloon color. C) By adjusting the temperature of the air. D) By changing the weight of the basket.
A) At sea level. B) Above 10,000 feet. C) Between 1,000 and 3,000 feet. D) Under 500 feet. |