In the same science fair, Tina asks the question ‘Does caffeine increase the heart rate of an earthworm?

In the same science fair, Tina asks the question “Does caffeine increase the heart rate of an earthworm?” In Test 1, she measures the heart rate by looking at the earthworm under a microscope, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm’s skin and measures the rate again. In this test, the heart rate is 68 bpm. 6) What is the Independent/Manipulated variable? 7) What is the Dependent/Responding variable? 8) Tina’s experiment should have included a hypothesis. In a complete sentence, suggest a hypothesis for Tina’s experiment. You may use an if/then statement.

Independent variable- effect of caffeine Dependent variable- heart rate Hypothesis- If a stimulant such as caffeine is administered to earthworm, then its heart rate increases. Explanation: The experiment is based on the research question; “Does caffeine increase the heart rate of an earthworm?” We can see from this research question that the independent variable is the effect of caffeine and the response it produces is a change in the heart rate (the dependent variable) This now leads us to a hypothesis that states thus; ‘If a stimulant such as caffeine is administered to earthworm, then its heart rate increases.’

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A hypothesis is usually an if then because statement, but the answer will differ as there may be multiple hypotheses to use for a single experiment. If an earthworm had an intake of caffeine, then their heart rate would increase because it would happen the same for humans as well.

If caffeine is applied to earthworms, then the earthworm’s heart rate will increase.

The Answer is C. Explanation: sorry i took awhile

Does caffeine increase the rate of an earthworm yes

Answer 6

In Test 1, the worm is observed in its natural state, making that the control group.

The independent variable is the one that does not change depending on other variables – so here it would be the presence or the absence of caffeine – this is dependent on Tina’s actions, but not on other variables in the experiment. The dependent variable is the heart rate – it is assumed to depend on the presence or absence of caffeine. A hypothesis could be that “Caffeine causes an increase of heart rate in earthworms” – and this hypothesis is what the experiment is testing.

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