Particles and Matter
Everything is made of _________.
Particles
When water _______ heat energy it turns into ice
loses
___________ pulls on particles, so things with more particles have more weight.
Gravity
_______ are tools that make it easier for people to do work.
Simple machines
Most heat energy on Earth come from ________.
the sun
_______ is how many particles are in something.
Mass
If ice _____ heat energy it turns into water
gains
The Earth has a lot of gravity because it is so _______.
big
A pulley changes a down pull into _______.
an up pull
Matter can ________ if we add or remove heat energy.
change forms
________ is how much space something takes up.
Volume
If we quickly add a lot of heat to water, it will ____.
boil
When two things rub together they make _____.
friction
The balance point of a lever is called _____
fulcrum
Heat energy moves easily through some kinds of matter. These materials are called ______.
conductors.
_______ is how close together the particles are.
Density
All liquids can turn into _______.
vapor
Rubbing a _____ surface has less friction than rubbing a _____ surface.
smooth : rough
What kind of machine is a pencil sharpener?
We can malke heat energy by burning ____ like ____,____, and _____.
fuels : wood, coal, and oil
Are you more or less dense than a rock?
I am less dense than a rock.
Where do water droplets on the side of a cold glass come from? Why?
The drops come from water in the air. The water condenses because it touches the cold surface.
Why do objects have weight?
Objects have weight because gravity pulls on their particles.
How are pulleys and levers the same?
They make it easier to lift things.
When are good heat insulators important?
It is hard for heat energy to move through these materials.
Winter