1. How to write a hypothesis
If I do this(1), then this will happen (2)
1 independent (manipulated) variable
2 dependent (responding) variable

2. If you open a faucet, then it will increase the flow of water.
You observe that the water flow increases.
Independent Variable (what I change)
Water faucet opening (closed, half open, fully open)
Dependent Variable (what I observe)
Amount of water flowing measured in liters per minute

3. Examples
If the temperature of a cup of water is increased, then it will increase the amount of sugar that dissolves in the water.
If the temperature of a gas is increased, then the volume will increase.
If a plant receives fertilizer, then it will grow to be bigger than a plant that does not receive fertilizer.
If I put fenders on a bicycle, then they will keep the rider dry when riding through puddles.

4. Your Hypothesis should be written in an if…then…because format
If and then are your variables
Because is what you think is going to happen.