ENV 101 Ch. 1 & 2 H.W.

If a scientist makes an observation and carries out an experiment to explain that observation, he or she is conducting __________.

hypothesis-driven science

In a controlled experiment, if a researcher wants to examine the effect of radon exposure to rat longevity, which one would be the independent variable?

radon exposure

Identify which type of feedback loop each process represents. Drag the positive or negative feedback loop on the left to each process on the right. Terms may be used once, more than once, or not at all.

1. A snowball rolling down a hill accumulates snow and becomes larger, which increases its speed, causing it to increase its size and speed even more. Positive 2. Increasing air temperatures from global warming speed up the melting of glaciers, exposing darker rocks underneath the ice. The dark surfaces absorb more sunlight, causing further increases in temperature and accelerated glacier melting. Positive 3. A dog pants as it lies in the hot summer sun, releasing excess body heat to the environment and lowering its body temperature to its stable state. Negative 4. A bull on the edge of a herd of cattle panics when it hears a loud noise and begins to run. Five nearby cattle sense the panic and also begin to run. This causes another 15 cattle to panic. Eventually, all 100 cattle in the herd panic and stampede. Positive 5. You invest $1,000 in a savings account and reinvest the 5% interest you earn. The interest makes the amount of money in the account larger, so it earns even more interest. After 20 years, the account contains more than $2,600 and is still growing. Positive 6. When blood sugar levels rise after eating a meal, the pancreas releases the hormone insulin, stimulating cells to take up sugar from the blood. When blood sugar levels drop, the pancreas releases another hormone to stop sugar uptake by cells. Negative

Can you sequence the steps in the eutrophication process that occurs in a body of water? Drag each statement to the appropriate location in the flowchart of the eutrophication process.

1. Nutrients enter a waterway in elevated concentration. 2. Nutrients promote phytoplankton growth, and increases phytoplankton density in the water. 3. More phytoplankton die and settle to the bottom, where they are metabolized by bacteria. 4. Hypoxic conditions arise in the deep water above the sediment. 5. Aquatic life in and near sediment flees or suffocates.

Each of the terms listed relates to the process of science and the scientific method. How well do you understand these terms? Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

Scientists use a general process known as the scientific method to ask and answer questions about natural phenomena. A hypothesis is a testable statement that proposes an explanation for a set of observations. It leads to predictions that can be tested by an experiment. A prediction describes specific results that can be expected if a hypothesis is true. A theory is broader in scope than a hypothesis, is supported by a large body of evidence, and generates many new hypotheses. A scientific experiment often involves both a treatment and a control, which are alike except for the variable that the experiment is designed to test. A variable is a factor that is either manipulated or measured in an experiment. A correlation is a quantitative relationship between variables. A review process is in place to make sure that no bias has skewed the results of an experiment.

The main advantage of observational studies and natural experiments over manipulative studies is that natural experiments __________.

are able to test hypotheses in the field and with large study areas

Which of the following is the study of how the natural world works, how our environment affects us, and how we affect our environment?

environmental science

In scientific research, the strongest form of evidence comes from __________.

experimentation

Which one of the following represents quantitative data?

levels of nitrate pollution in local waterways

If an experiment fails to disprove a hypothesis, then __________.

this lends support to the hypothesis but does not prove it is correct