Question

Many farmers and gardeners compost their plant and animal waste. The living material naturally decays in compost bins, forming a dirt-like substance that’s rich in nutrients. The next season, farmers use this substance as a natural fertilizer for their crops. A biology student has grown tomato plants for several years. Until now, he used an artificial fertilizer formulated for tomato plants. This fertilizer caused his plants to grow faster and taller than they grew in unfertilized soil. The student wants to know whether using natural compost will cause his tomato plants to grow faster and taller than his artificial fertilizer.

What are the student’s observations and inferences before he starts his investigation?
What’s the student’s scientific question?
Construct at least two possible hypotheses for the student’s experiment.
Choose one of the hypotheses to make a prediction.
How would you conduct your investigation? In your answer, explain your independent and dependent variables.
How does the design of your experiment control for outside factors that may affect the results?
How do you plan to analyze and communicate your results?

Answer 1

The student has been using artificial fertilizer, resulting in faster and taller tomato plant growth. Artificial fertilizer likely contains specific nutrients that promote rapid tomato plant development.

Scientific Question:

Will using natural compost as a fertilizer lead to faster and taller growth in tomato plants compared to artificial fertilizer?

Hypothesis: Tomato plants treated with natural compost will exhibit faster and taller growth than those treated with artificial fertilizer.

Hypothesis: There will be no significant difference in growth between tomato plants treated with natural compost and artificial fertilizer.

Chosen Hypothesis and Prediction:

Chosen Hypothesis: Tomato plants treated with natural compost will exhibit faster and taller growth than those treated with artificial fertilizer.

Prediction: If natural compost provides essential nutrients, the plants treated with it will outperform those treated with artificial fertilizer.

Experiment Design:

Independent Variable: Type of fertilizer (natural compost or artificial fertilizer)

Dependent Variables: Growth rate (height and size) of tomato plants

Controlled Variables: Soil type, water, sunlight, temperature, and initial plant conditions

Control for Outside Factors:

Randomize plant placement, maintain consistent watering and sunlight exposure, and use identical initial plant conditions to minimize external influences.