We can learn about the world around us by taking measurements. Different tools help us make different kinds of measurements. Here are a few tools for measuring.
ThermometerPAGA DESIGN/GETTY IMAGES
A thermometer measures temperature. It tells us how hot or cold something is.
A scale measures weight. It tells us how much something weighs. Which of these two loads is heavier?
RulerFROM TOP: JANGELTUN (2); DNY55/GETTY IMAGES
A ruler measures length. It tells us how long or short something is. How many inches long is this eraser?
ClockPAUL BRICKNELL—GETTY IMAGES
A clock measures time in hours and minutes. The round clock is analog . It has hands that move. They point at the numbers to show the time. The black clock is digital . It has only numbers.
Did You Know?RICHARD CUMMINS—GETTY IMAGES
This is a sundial . It is one of the oldest tools for telling time. A sundial has markings. They stand for the hours of daylight. It also has a pointer. The pointer casts a shadow. The shadow moves as the sun moves. This is one way people could tell time long ago.