NTS - National Testing Service Everyday Science Concepts Questions and Answers 1 — Questions and Answers
Question 1: Why does a large steel ship float on water, while a small steel nail sinks?
- The steel used in ships is a special, lighter alloy.
- The ship is hollow and its overall shape displaces a large volume of water. (Correct answer)
- The ocean's salt content makes the water dense enough to support the ship.
- The ship's engine creates an upward force that keeps it afloat.
Correct answer: The ship is hollow and its overall shape displaces a large volume of water.
According to Archimedes' principle, an object floats if the upward buoyant force is greater than or equal to its weight. This buoyant force is equal to the weight of the fluid the object displaces. A ship's large, hollow shape displaces a massive volume of water, creating a buoyant force strong enough to support its own weight. A nail, being small and solid, displaces very little water, resulting in a buoyant force that is much less than its weight, causing it to sink.
Question 2: What is the primary gas absorbed from the atmosphere by plants during photosynthesis?
- Oxygen
- Nitrogen
- Carbon Dioxide (Correct answer)
- Hydrogen
Correct answer: Carbon Dioxide
Photosynthesis is the process plants use to convert light energy into chemical energy. They take in carbon dioxide (COâ‚‚) from the atmosphere and water (Hâ‚‚O) from the soil. Using sunlight, they convert these into glucose (sugar for food) and release oxygen as a byproduct.
Question 3: Which of the following common household substances is an acid?
- Baking soda solution
- Soap
- Vinegar (Correct answer)
- Bleach
Correct answer: Vinegar
Vinegar is an acid because it is a dilute solution of acetic acid, which gives it a pH value below 7. Baking soda, soap, and bleach are all common examples of bases (alkaline substances), which have a pH value above 7.
Question 4: The changing of seasons on Earth is primarily caused by which of the following?
- The Earth's changing distance from the Sun.
- The gravitational pull of the Moon.
- The tilt of the Earth's axis of rotation. (Correct answer)
- The variation in the Sun's energy output.
Correct answer: The tilt of the Earth's axis of rotation.
Earth's axis is tilted at an angle of about 23.5 degrees. As Earth orbits the Sun, this tilt causes different parts of the planet to receive more direct sunlight at different times of the year. When a hemisphere is tilted towards the Sun, it experiences summer; when it is tilted away, it experiences winter.
Question 5: An astronaut on the Moon strikes a rock with a hammer, but their fellow astronaut standing nearby hears nothing. Why is this?
- Sound requires a medium, like air or water, to travel, and the Moon has no atmosphere. (Correct answer)
- The helmets worn by astronauts block all external sound.
- The gravitational pull on the Moon is too weak for sound to travel.
- The sound produced is too quiet to be heard from that distance.
Correct answer: Sound requires a medium, like air or water, to travel, and the Moon has no atmosphere.
Sound travels as a wave of vibrations through a medium (solid, liquid, or gas). The Moon is essentially a vacuum with no atmosphere. Without a medium like air for the vibrations to travel through, sound waves cannot propagate, and therefore no sound can be heard.
Question 6: Which of the following organs is primarily responsible for filtering waste products from the blood and producing urine?
- Liver
- Kidneys (Correct answer)
- Lungs
- Stomach
Correct answer: Kidneys
The kidneys are the main organs of the urinary system. Their primary function is to filter the blood to remove waste products and excess water, which are then excreted from the body as urine. The liver has many metabolic functions, the lungs are for respiration, and the stomach is for digestion.
NTS - National Testing Service Everyday Science Concepts Questions and Answers 1
Why does a large steel ship float on water, while a small steel nail sinks?