Poisons can be this
Toxic
This can be high on a sunny hot day
Temperature
If you are sick you take your temperature with what?
Thermometer
You can add this to your pool?
Alkaline
When it rains the water drys up by?
evaporate
Your car battery needs this?
Acid
When you need to find an answer?
Solution
Detectives have this in an investigation
Theory
When you are in Science you can?
Experiment
The way you go about doing an expermient
Method