1.
How many more bones do babies have compared to adults?
Correct Answer
D. 100
Explanation
Babies have around 300 bones at birth, while adults have 206 bones. As the baby grows, some of its bones fuse together, resulting in a decrease in the total number of bones. Therefore, babies have approximately 100 more bones compared to adults.
2.
What's the most interesting fact about the Eiffel Tower?
Correct Answer
D. It can be 15 cm taller during summer
Explanation
The correct answer is "It can be 15 cm taller during summer." The Eiffel Tower can actually grow by up to 15 centimeters (about 6 inches) in height during the summer due to thermal expansion. When the iron structure heats up from the sun, the metal expands, causing the tower to increase in height. This fascinating phenomenon is a result of the basic principles of physics and demonstrates the impact of temperature changes on large metal structures. Understanding such facts about the Eiffel Tower adds to its allure and showcases the intriguing interplay between engineering and natural forces.
3.
Where does 20% of the earth's oxygen come from?
Correct Answer
D. The Amazon rain forest
Explanation
The Amazon rainforest is known as the "lungs of the Earth" due to its significant contribution to the production of oxygen. The rainforest is home to a vast number of plant species, and through the process of photosynthesis, these plants release oxygen into the atmosphere. It is estimated that the Amazon rainforest alone produces about 20% of the Earth's oxygen, making it a crucial source for maintaining the planet's oxygen balance.
4.
Which metal explodes when in contact with water?
Correct Answer
A. Potassium
Explanation
Potassium is a highly reactive metal that reacts vigorously with water. When potassium comes in contact with water, it undergoes a violent exothermic reaction, resulting in the release of hydrogen gas and the formation of potassium hydroxide. The heat generated during this reaction is sufficient to ignite the hydrogen gas, causing a small explosion. Therefore, potassium is the metal that explodes when in contact with water.
5.
How heavy is a teaspoon of a neutron star?
Correct Answer
A. 6 billion tons
Explanation
A teaspoon of a neutron star is incredibly heavy, weighing approximately 6 billion tons. Neutron stars are incredibly dense and compact, formed from the remnants of a massive star that has undergone a supernova explosion. The immense gravitational force compresses the star's mass into a small volume, resulting in such extreme density. Due to this, even a small amount of matter from a neutron star can have an astonishingly high mass, making a teaspoon of it weigh billions of tons.
6.
How close is Hawaii moving towards Alaska every year?
Correct Answer
D. 7.5 cm closer
Explanation
The correct answer is 7.5 cm closer. Hawaii is moving towards Alaska at a rate of approximately 7.5 centimeters (about 3 inches) per year. This movement is due to the tectonic activity of the Pacific Plate, which is gradually shifting in a northwesterly direction. Over millions of years, this slow but consistent movement will significantly change the positions of these landmasses relative to each other. Understanding tectonic plate movements helps scientists predict geological events and understand the Earth's dynamic nature.
7.
In how many years will it be too hot on earth to be able to live on it?
Correct Answer
C. 2.3 billion years
Explanation
Based on current scientific understanding, the gradual increase in the Earth's temperature, known as global warming, is expected to continue at a relatively slow pace. It is estimated that in about 2.3 billion years, the Earth will become too hot to sustain life as we know it. This prediction takes into account various factors such as the gradual increase in solar radiation over time and the eventual depletion of atmospheric carbon dioxide, which plays a role in regulating the planet's temperature. Therefore, the correct answer is 2.3 billion years.
8.
How long does it take for light to travel from the sun to the earth?
Correct Answer
C. 8 minutes and 19 seconds
Explanation
Light travels at a speed of approximately 186,282 miles per second (299,792 kilometers per second). The distance between the sun and the earth is about 93 million miles (150 million kilometers). Therefore, it takes light about 8 minutes and 19 seconds to travel from the sun to the earth.
9.
How strong is stomach acid?
Correct Answer
A. Strong enough to dissolve stainless steel
Explanation
Stomach acid is extremely strong and has a pH level of around 1-3, which makes it highly acidic. This acidity is necessary for the digestion of food and the breakdown of proteins. The high concentration of hydrochloric acid in the stomach allows it to break down various substances, including metals like stainless steel. However, it is important to note that the stomach lining is protected from the corrosive effects of stomach acid by a layer of mucus.
10.
Which planet is known to spin clockwise?
Correct Answer
A. Venus
Explanation
Venus is known to spin clockwise. Unlike most planets in our solar system, Venus rotates on its axis in the opposite direction to its orbit around the sun. This means that if you were standing on Venus, the sun would rise in the west and set in the east. This retrograde rotation is thought to have been caused by a collision or gravitational interactions with other celestial bodies in the early history of the planet.