What force pulls objects toward Earth?
gravity
What organ pumps blood in the body?
heart
What is the chemical formula of water?
H2O
What is the outer layer of Earth called?
crust
What star is in the center of our Solar System?
sun
What do we call energy of movement?
kinetic energy
What gas do people need to breathe?
oxygen
What state of matter has no fixed shape and fills a container?
gas
What natural event causes shaking of the ground?
earthquake
What planet is closest to the Sun?
mercury
What unit is used to measure force?
newton
What is the basic unit of life?
cell
What gas do plants take from the air?
carbon dioxide
What tool measures earthquakes?
seismograph
What planet is famous for its rings?
saturn
What device measures electric current?
ammeter
What process do plants use to make food from sunlight?
photosynthesis
What do we call a change from solid to liquid?
melting
What is the hot liquid rock under Earth called?
magma
What is Earth’s natural satellite?
moon
What law explains the relation between voltage, current, and resistance?
ohm’s law
What system helps the body move?
muscular system
What is the smallest part of an element?
atom
What is the movement of Earth’s plates called?
plate tectonics
Who was the first human in space?
yuri gagarin