Temperature and pressure are really important in telling us if something is a solid, liquid, or gas.

Temperature:

• When the temperature goes up, solids usually turn into liquids, and liquids can change into gases.
• For instance, ice melts into water when it reaches 0 degrees Celsius.

Pressure:

• When we increase pressure, it can push gases into liquids. This is how carbonated drinks work!
• On the other hand, if we lower the pressure, gases will spread out and take up more space.

So, simply put: when you heat things up and lower the pressure, you can often change how matter behaves!