BMST Science 5 — Questions and Answers
Question 1: Which of the following best describes a chemical change?
- Ice melting into water
- Sugar dissolving in water
- Iron rusting over time (Correct answer)
- Glass breaking into pieces
Correct answer: Iron rusting over time
Rusting is a chemical change because iron reacts with oxygen to form a new substance, iron oxide.
Question 2: What force keeps planets in orbit around the Sun?
- Electromagnetic force
- Nuclear force
- Gravity (Correct answer)
- Friction
Correct answer: Gravity
Gravity is the attractive force between masses that keeps planets in their orbital paths around the Sun.
Question 3: In a food chain, organisms that make their own food using sunlight are called:
- Consumers
- Decomposers
- Producers (Correct answer)
- Predators
Correct answer: Producers
Producers (mainly plants) use photosynthesis to convert sunlight into food energy.
Question 4: Which type of wave requires a medium to travel through?
- Radio wave
- Gamma ray
- Mechanical wave (Correct answer)
- Light wave
Correct answer: Mechanical wave
Mechanical waves, such as sound, need a physical medium (solid, liquid, or gas) to propagate.
Question 5: What is the term for the number of protons in the nucleus of an atom?
- Mass number
- Atomic number (Correct answer)
- Neutron number
- Isotope number
Correct answer: Atomic number
The atomic number defines an element and equals the number of protons in its nucleus.
Question 6: Which of the following is an example of a renewable energy source?
- Coal
- Natural gas
- Nuclear fission
- Wind power (Correct answer)
Correct answer: Wind power
Wind power is renewable because wind is a naturally replenishing resource that will not run out.
Question 7: During photosynthesis, plants absorb carbon dioxide and release which gas?
- Nitrogen
- Hydrogen
- Oxygen (Correct answer)
- Carbon monoxide
Correct answer: Oxygen
Photosynthesis converts CO₂ and water into glucose and oxygen using light energy.
BMST Science 5
Which of the following best describes a chemical change?