The best hypothesis for the experiment investigating the impact of salt water on the growth of plants is:
If salt water is used to water plants, then the plants will not grow as tall as those watered with tap water.
Here's why this is the correct answer:
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Specificity: This hypothesis clearly states the expected outcome of the experiment. It specifies a condition (using salt water) and an expected result (plants not growing as tall as those watered with tap water).
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Testable: The hypothesis is testable through experimentation. The researcher can set up an experiment with two groups of plants: one receiving salt water and the other receiving tap water, then measure their growth.
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Based on existing knowledge: The hypothesis is grounded in biological and botanical principles. High salt concentrations in the soil can lead to osmotic stress for plants, which often results in stunted growth.
The other responses do not serve as effective hypotheses:
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"Plants need water to grow, and they should also be exposed to sunlight." This is a general statement about plant growth but does not specifically relate to the effect of salt water versus tap water.
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"I will add salt water to plants and observe how they grow." This is more of a statement of intent rather than a hypothesis. A hypothesis should predict an outcome based on an experimental condition.
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"I think salt water will help plants grow taller." This goes against the established understanding of plant biology, as salt water typically hampers growth rather than promotes it.
Thus, the first option provides a clear, specific, and testable hypothesis that directly addresses the research question.
5 answers