Lesson 1.5 - Fertilizers and Plant Growth

In any experiment, the variable that you change is the manipulated variable.  The variable that changes as a result of what you change is the responding variable. 

Read pages 294 and 295 in the textbook. 

You need not do the lab work, but please study the following chart and answer the questions that follow before checking your answers.

Bottle Amount of Fertilizer Color on Day 0 Color on Day 2 Color on Day 4 Color on Day 6 Color on Day 8 Color on Day 10
1 (control) 0 g pale green no change no change no change no change no change
2 1 g pale green increase in green colour little or no change little or no change little or no change little or no change
3 3 g pale green increase in green colour increase in green colour little or no change little or no change little or no change
4 5 g pale green increase in green colour increase in green colour increase in green colour little or no change little or no change
5 10 g pale green increase in green colour increase in green colour little or no change little or no change little or no change

 

Question 1. Answer questions 1 and 2 under Analyze on page 295 of your textbook.

Question 2. Answer questions 3 to 6 under Conclude and Apply on page 295 of your textbook.

Question 3. What is the manipulated variable in the above experiment?

Question 4. What is the responding variable in the above experiment?

 

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. Answer questions 1 and 2 under Analyze on page 295 of your textbook.

1.   The most growth was shown where there was five grams of fertilizer.  The least change was where there was no fertilizer.

2.    Bottle 1 shows that fertilizer is essential to plant growth. 

Question 2. Answer questions 3 to 6 under Conclude and Apply on page 295 of your textbook.

3.    Up to a certain point, fertilizer promotes plant growth.

4.    Nitrogen, phosphorus, and potassium are usually present in the largest amounts.

5a.    Producers may increase for a while, but then they may slow down and even die.

5b.    Consumers may increase for a while, but they may also die if the lake capacity is exceeded.

5c.    Decomposers will increase greatly, but after the oxygen is used up, most life in the lake will die.

6.    In spring, the cattle wastes enter the pond and allow algae to grow.

Question 3. What is the manipulated variable in the above experiment?

The manipulated variable is the amount of fertilizer.

Question 4. What is the responding variable in the above experiment?

The responding variable is the increase in the green colour.  

 


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