Name four ways that you can change the rate of a chemical reaction.

Increasing the temperature. 
Increasing the concentration (in solution).
Increasing the pressure (in gases).
Increasing the surface area of a solid.

1)By adding a catalyst. Catalyst are agents which speed up or slow down the rate of a chemical reaction.
2)By increasing temperature. When the temperature is increased, it increases the rate of collision. And according to the collision theory, collision has to take place for a chemical reaction to occur.
3)By increasing pressure. This is just like temperature, but for gases.
4) By increasing surface area. In this, it means that when more of a reactant is exposed, the reaction is faster. For example, the reaction between HCl and powdered marble is faster than HCl and pieces of marble. Hope i helped. Have a nice day.

Gallium melts near room temperature and has one of the largest  liquid  ranges of any metal, so it has found use in high temperature thermometers.

Engineers have contribute to society in many ways like making the technology we use today or any type of power energy material