Let me work through each question step by step.
Question 1: In a controlled experiment,
In a controlled experiment, we need to understand what makes it "controlled." A controlled experiment has:
- One independent variable (the thing we change)
- All other variables kept the same (controlled variables)
- A control group and experimental group(s) to compare
Looking at the options:
a. A control group is compared with one or more experimental groups - This is TRUE. That's how we see if our changes made a difference.
b. There are at least two variables - This is misleading. We have ONE independent variable and many controlled variables.
c. All factors should be different - FALSE. Only ONE factor should be different; everything else stays the same.
d. A variable is not needed - FALSE. We definitely need variables.
Answer:
a
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Question 2: Which factor is the Independent Variable in this experiment?
The independent variable is what we CHANGE on purpose to test something.
Looking at the table:
- Type of Bee: All honeybees (same)
- Time of Day: All 9:00 am - 10:00 am (same)
- Type of Plant: All Portland Rose (same)
- Flower Color: Red, Yellow, White, Pink (DIFFERENT!)
Since flower color is the only thing that changes between groups, that's the independent variable.
Answer:
d
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Question 3: Which of the following ideas could be tested with this experiment?
The experiment tests whether bees prefer different colored flowers because:
- Everything else is the same (bee type, time, plant type)
- Only the flower color changes
So we can test if honeybees have a preference for certain colors.
Looking at options:
a. Honeybees prefer rose plants - NO, we're only using roses, can't compare to other plants
b. Honeybees prefer red flowers - YES! We can see if they visit red flowers more than yellow, white, or pink
c. Honeybees prefer morning flowers - NO, all observations are in the morning
d. Honeybees prefer Portland roses between 9-10 am - NO, we're not testing time or comparing plants
Answer:
b
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Question 4: Why is Portland rose included in all groups?
When we keep something the SAME in all groups, it's called a "control variable" or "constant." We do this so we know that any differences we see are ONLY because of what we changed (flower color), not because of different plants.
Looking at options:
a. The type of plant is a control variable; any type of flowering plant could be used if all plants were of the same type - YES! This is exactly right. We keep it constant so it doesn't affect our results.
b. Testing if bees prefer Portland rose over other flowers - NO, we're not comparing different plants
c. An experiment should always have more than one variable - NO, that's wrong. Good experiments have only ONE independent variable.
d. Portland rose is very common - NO, that's not the scientific reason
Answer:
a
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Final Answer:
1. a
2. d
3. b
4. a
Parent Tip: Review the logic above to help your child master the concept of 7th grade science questions and answers.
