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