Human Body System
Which body system controls the body and sends messages using the brain, spinal cord, and nerves?
Nervous system.
Which simple machine is a ramp?
An inclined plane.
What is the difference between weather and climate?
Weather is the daily condition of the atmosphere. Climate is the usual weather pattern over a long time.
What are the three common states of matter?
Answer: Solid, liquid, and gas.
What force keeps planets orbiting the Sun?
Answer: Gravity.
How do the respiratory and circulatory systems work together?
The respiratory system brings oxygen into the lungs, and the circulatory system carries oxygen through the blood to the body.
How does a pulley make lifting easier?
It can change the direction of the force and may reduce the effort needed to lift a load.
Why does warm air rise?
Warm air is less dense than cold air, so it rises.
What happens to particles when matter is heated?
Answer: The particles move faster and spread farther apart.
What causes day and night on Earth?
Answer: Earth’s rotation on its axis.
Why does your heart beat faster when you exercise?
Your muscles need more oxygen and energy, so the heart pumps blood faster.
A student uses a lever to lift a heavy rock. How can moving the fulcrum closer to the rock help?
It gives the student a longer effort arm, so less force is needed to lift the load.
What happens when a cold air mass meets a warm air mass?
A weather front forms, which can cause clouds, rain, storms, or temperature changes.
Why is evaporation considered a change of state?
Answer: A liquid changes into a gas when particles gain enough energy to escape into the air.
What causes the seasons on Earth?
Answer: Earth’s tilted axis and its revolution around the Sun.
How does the excretory system help keep the body healthy?
It removes wastes and extra water from the blood, helping the body stay balanced.
Why does a pulley system with more than one pulley make lifting easier?
Answer: It spreads the weight of the load over more sections of rope, so less force is needed.
What is the difference between a cold front and a warm front?
Answer: A cold front happens when cold air pushes under warm air. A warm front happens when warm air moves over colder air.
Explain the difference between a physical change and a chemical change.
Answer: A physical change changes the form or state of matter, but no new substance is made. A chemical change creates a new substance.
Why do we see different phases of the Moon?
Answer: As the Moon orbits Earth, we see different amounts of its sunlit side.
How do the respiratory and excretory systems both remove waste from the body?
The respiratory system removes carbon dioxide when we breathe out, and the excretory system removes liquid waste through urine.
A student uses scissors to cut paper. Which simple machines are working together?
Answer: Scissors use levers for the handles and wedges for the cutting blades.
How does the Sun affect weather on Earth?
Answer: The Sun heats Earth unevenly, which creates temperature differences, air movement, wind, clouds, and precipitation.
Why does ice float on water?
Answer: Ice is less dense than liquid water, so it floats.
Why does Earth have day and night, but not every place on Earth has day and night at the same time?
Answer: Earth rotates on its axis. The side facing the Sun has daytime, while the side facing away from the Sun has nighttime.