• What is the lightest element?
  The lightest element is hydrogen. It has just one proton in its ...

• What substance has the highest melting point?
  The metal with the highest melting point is tungsten, which melts at ...

• What substance has the lowest freezing point?
  Mercury has the lowest freezing point of any metal -38.87°C ...

• What is a plasma?
  A plasma is the rare fourth state of matter. It occurs only when a ...

• When do things freeze?
  Things freeze from liquid to solid when they reach the freezing ...

• When do things boil?
  Things boil from liquid to gas when they reach boiling point, which ...

• When do things melt?
  Things melt from solid to liquid on reaching a temperature called the ...

• What is pressure?
  Pressure is the amount of force pressing on something. Air pressure ...

• How does pressure change?
  If you squeeze a gas into half the space, the pressure doubles (as ...

• What is an atomic bomb?
  An atomic bomb or A-bomb is one of the two main kinds of nuclear ...