- Hypothesis: All forks have three tines.
Disproven if you find any fork with a different number of tines.
- Hypothesis: There is no relationship between smoking and lung cancer.
While it is difficult to establish cause and effect in health issues, you can apply statistics to data to discredit this hypothesis or to support it, if the rates of lung cancer are the same between smokers and non-smokers.
- Hypothesis: Plants require liquid water to survive.
Disproven if you find a plant that doesn't need it.
- Hypothesis: Cats do not show a paw preference (cat equivalent to being right- or left-handed).
You could gather data about the number of times cats bat at a toy with either paw and analyze the data to determine whether cats, on the whole, favor one paw over the other. Be careful here, because individual cats, like people, might (or might not) express a preference.
- Hypothesis: If plants are watered with a 10% detergent solution, their growth will be negatively affected.
Some people prefer to state a hypothesis in an "If, then" format. An alternate hypothesis might be: Plant growth will be unaffected by watering with a 10% detergent solution. What hypothesis would you use?
You're welcome to post a reply offering additional hypothesis examples or discussing the type of hypothesis you prefer to formulate and test.