NTS - National Testing Service Everyday Science Concepts Questions and Answers

Question 1

Why does a large steel ship float on water, while a small steel nail sinks?

Accepted Answer

The ship is hollow and its overall shape displaces a large volume of water.

Answer

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?

Accepted Answer

Carbon Dioxide

Answer

Photosynthesis is the process plants use to convert light energy into chemical energy. They take in carbon dioxide (CO₂) from the atmosphere and water (H₂O) 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?

Accepted Answer

Vinegar

Answer

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?

Accepted Answer

The tilt of the Earth's axis of rotation.

Answer

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?

Accepted Answer

Sound requires a medium, like air or water, to travel, and the Moon has no atmosphere.

Answer

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.

NTS - National Testing Service Practice Test

NTS - National Testing Service Practice Test

NTS - National Testing Service Everyday Science Concepts Questions and Answers