ICAS Science 2 — Questions and Answers
Question 1: A student leaves a damp cloth on a windowsill in sunlight. After an hour, the cloth is dry. Which process best explains this?
- Condensation
- Evaporation (Correct answer)
- Precipitation
- Sublimation
Correct answer: Evaporation
Evaporation occurs when liquid water absorbs heat energy and changes into water vapor, drying the cloth.
Question 2: Which organ system is primarily responsible for removing carbon dioxide from the human body?
- Digestive system
- Circulatory system
- Respiratory system (Correct answer)
- Excretory system
Correct answer: Respiratory system
The respiratory system expels carbon dioxide from the body when we exhale through the lungs.
Question 3: A magnet is brought near a pile of mixed sand and iron filings. What will happen?
- Both sand and iron filings are attracted
- Only the iron filings are attracted (Correct answer)
- Only the sand is attracted
- Neither material is attracted
Correct answer: Only the iron filings are attracted
Magnets attract ferromagnetic materials like iron, but have no effect on non-magnetic materials like sand.
Question 4: Plants appear green because their leaves mainly:
- Absorb green light and reflect all others
- Reflect green light and absorb other wavelengths (Correct answer)
- Produce green-colored water
- Contain green-colored soil minerals
Correct answer: Reflect green light and absorb other wavelengths
Chlorophyll in plant leaves absorbs red and blue light for photosynthesis and reflects green light, making plants appear green.
Question 5: Which of the following is a chemical change rather than a physical change?
- Ice melting into water
- Sugar dissolving in tea
- Wood burning in a fire (Correct answer)
- Glass shattering into pieces
Correct answer: Wood burning in a fire
Burning wood is a chemical change because it produces new substances (ash, carbon dioxide, and water vapor) that cannot easily be reversed.
Question 6: The Moon appears to change shape over the course of a month. This is because:
- The Moon physically shrinks and grows
- Earth's shadow blocks different parts of the Moon
- We see different portions of the Moon's lit side as it orbits Earth (Correct answer)
- Clouds on the Moon cover its surface
Correct answer: We see different portions of the Moon's lit side as it orbits Earth
As the Moon orbits Earth, we see different fractions of its sunlit half, creating the appearance of changing phases.
Question 7: A bird has hollow bones. How does this adaptation most likely help the bird?
- It makes the bird heavier for better balance
- It reduces the bird's body weight to aid in flight (Correct answer)
- It helps the bird store more energy
- It protects the bird from predators
Correct answer: It reduces the bird's body weight to aid in flight
Hollow bones reduce overall body mass, making it easier for birds to achieve and sustain flight.
ICAS Science 2
A student leaves a damp cloth on a windowsill in sunlight.
After an hour, the cloth is dry.
Which process best explains this?