Biology lab questions

In the pillbug experiment, your hypothesis

was related to the environment pillbugs prefer?

A cover slide should be used to protect the objective lens from specimen on the slide and provides a level surface to make viewing easier.

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Place the four phases of the scientific method in order.

Hypothesis Experiment Analysis Report

You should use the graph generated from your data to see if your hypothesis is supported.

True

experiment

carry out the strategy, collect measurements

hypothesis

formulate a hypothesis and create a strategy

Match each item with the correct base unit of the metric system used to measure the item. Meter Liter Temperature Gram

height of a tree amount of water in a test tube heat of a water bath powdered chemical

In the pillbug experiment, an important part of the experimental strategy was to

make observations at regular intervals.

In the pillbug experiment, the substance used as the control was

sand.

There are two, two-sided dishes in the pillbug experiment. In one dish, you should have placed sand in both sides. In the other dish, you should have placed ______ in one side and ______ in the other.

sand; cornstarch

In order to come to reliable conclusions about pillbug preferences, you needed to use the

scientific method.

Before you begin a scientific experiment, you should (Select all that apply)

state a hypothesis. decide on a strategy.

The tare button is used to zero (i.e., reset) the scale.

True The tare button will zero the scale.

When utilizing the scientific method, there are two types of variables. They are

dependent and independent.

Imagine that you wish to compare two different diets that will be fed to tadpoles raised in a lab. One diet is a meat-based fish food, and the other is the traditional diet of boiled lettuce. You want to see if the meat-based diet will be associated with an increase in the average weight of the tadpoles. In your experiment you keep all other factors, such as tadpole density per pan, temperature, pH, and the amount of food the same. The only difference between your control and experimental groups is the type of food the tadpoles receive. What is the independent variable for the tadpole diet experiment?

diet because it's changed

report

document results

analysis

draw graphs, evaluate the hypothesis

When determining the scope of an experiment, you need to consider (Select all that apply)

the outcome you will investigate. the factor that will vary.

Adding the oil provides increased resolving power of the objective lens. Decreasing the light will make the image more difficult to view. The coarse focus should only be used with the lower magnification objective lens.

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Obtain a clean slide and cover slip. Using a transfer pipette, obtain a drop of specimen and place onto the center of the slide. Carefully place the cover slip over the drop of specimen. Observe preparation under the 10X objective lens. Observe preparation under the 40X objective lens.

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The course adjustment knob locates the specimen in the focus plane.

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The fine adjustment knob fine-tunes the focus of the specimen.

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The objective lens 4x is scanning, 10x is low power, 40x is high power and 100x is oil immersion. The highest total magnification would be the oil immersion objective labeled 100x.

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The objective lens magnifies the specimen. The mechanical stage moves the slide back and forth and right to left. The iris diaphragm controls the amount of light on the specimen. The course adjustment knob controls the stage movement up and down.

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The objective lenses are mounted to a rotating nosepiece.

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The ocular lens (eyepiece) magnifies the specimen 10 times.

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To find the total magnification you must multiply the ocular lens magnification (10x) by the magnification of the objective lens. For example, if your objective lens is 10x and the ocular lens (eyepiece) is 10x, then your total magnification is 10 x 10= 100x.

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Assume you drink 250mL of soda out of a 1 liter soda bottle. How many liters are left?

0.75 liters Convert 1 liter to milliliters and subtract 250 mL to find remaining mL. Example: 1 liter = 1000 mL-250 mL = 750 mL.

In the pillbug experiment, how many pillbugs did you need to use to get good information for the experiment?

10

Pond water can contain many types of organisms. Which of the following are you most likely to find in a pond water sample? Please select all that apply.

Bacteria, algae, rotifers, human cells, and protozoa Human cells would need to be contrast stained to be visible. Virus are not visible with a brightfield microscope.

In the metric system, the base unit of temperature is the

Celsius. In the metric system, gram is the base unit for weight, meter is the base unit for length, liter is the base unit for a liquid and Celsius is the base for temperature.

After a period of time, most of the pillbugs appeared to spend most of their time on the side of the dish with sand, not cornstarch.

False

If the hypothesis in a scientific experiment is not supported, the experiment is considered a complete failure and must be repeated until a satisfactory outcome is reached.

False

In the pillbug experiment, it is important that measurements be taken twice: once at the beginning of the experiment, and once at the end of the experiment.

False

You do not need to pause to record your data as you perform your experiment. You can go back and estimate the values when the experiment is complete.

False

The centigram is the smallest unit of weight.

False A milligram is 1000 times smaller than a gram where as a centigram is only 100 times smaller than a gram.

On the Celsius scale, water freezes at 32 degrees.

False Boiling = 212ºF or 100ºC. Body Temperature = 98.6ºF or 37ºC. Freezing = 32ºF or 0ºC.

The metric scale of temperature is Fahrenheit.

False In the metric system, gram is the base unit for weight, meter is the base unit for length, liter is the base unit for a liquid, and Celsius is the base for temperature.

Why is it important to use the tare function when weighing an object placed in a beaker?

It allows you to weigh the object and disregard the beaker.

In the pillbug experiment, if the pillbugs in the experimental chamber would have moved to the side of the chamber with sand instead of cornstarch, what would you have concluded?

Pillbugs tend to prefer sand over cornstarch.

When measuring the volume of a liquid in a graduated cylinder, at which point should the measurement be taken?

at the meniscus Accurate volume measurements are taken at the bottom of the water level (meniscus) with your eye level parallel to the water level.

Some students consume large amounts of coffee and so-called energy drinks to help them stay alert when studying. You notice that many who engage in this practice seem to do poorly on exams. Suppose you want to investigate the relationship between caffeine consumption and exam performance. Which of the following statements would be an appropriate hypothesis?

Students who consume large amounts of caffeine while studying will have lower exam scores than those who consume less caffeine.

Imagine that you wish to compare two different diets that will be fed to tadpoles raised in a lab. One diet is a meat-based fish food, and the other is the traditional diet of boiled lettuce. You want to see if the meat-based diet will be associated with an increase in the average weight of the tadpoles. In your experiment you keep all other factors, such as tadpole density per pan, temperature, pH, and the amount of food the same. The only difference between your control and experimental groups is the type of food the tadpoles receive. Which is a good hypothesis for this tadpole experiment?

Tadpoles will be larger if fed a meat-based diet.

How is the metric system different than the standard United States system?

The metric system is based on units of 10.

What is the advantage of using a wet mount?

The motility of a specimen can be viewed under a microscope, The wet mount is a safer way to view pathogenic organisms, The specimen can be viewed as living cells, The contrast of a specimen is enhanced with the addition of water to the slide. Wet mount allow fast preparation with no special equipment. Organisms can be viewed in their living state and movement can be observed. Pathogenic organisms, which can make you sick, require special handling.

If you wanted to test whether or not a particular pain reliever was effective in the general population, you would need to design an experiment with an experimental group and a control group. What should be the only difference between these two groups?

Treatment: The experimental group should get the pain reliever, and the control group should get a placebo

The Celsius scale is primarily used in climate studies and industry.

True In the metric system, gram is the base unit for weight, meter is the base unit for length, liter is the base unit for a liquid, and Celsius is the base for temperature. Metric units are used in scientific research to ensure consistency of collected data.

When comparing the milligram, gram, microgram, and kilogram, the largest unit of weight is the kilogram.

True Milligram is 1/1000 the base, gram is the base, microgram is 1/1 million the base and kilogram is 1000x the base therefore kilogram is the largest unit of measurement.

In the pillbug experiment, did your results support your hypothesis? Why or why not?

Yes, my hypothesis was supported with the results. I stated that the pillbugs would prefer cornstarch to sand due to their interest in the food. As time passed during the experiment, you see more pillbugs migrate to the side of the dish with cornstarch while in the control group, the pillbugs remained the same because both sides were filled with sand.

In the metric system, the base unit of a liquid is the

liter.

According to the results of the pillbug experiment,

pillbugs tend to prefer cornstarch over sand.

When graphing your data, it is important to

place the dependent variable on the Y-axis.

When graphing your data, it is important that you

place the independent variable on the X-axis.

A student measured the weight of 10 male rats fed junk food compared to 10 male rats fed a healthy diet. The average weight of each group can be seen in the table below. What important variable did the student hold constant when she designed this experiment?

the sex of the rats The experimental groups would not be equal or comparable if one group was male and one was female. For meaningful data, both groups should be as constant as possible while changing independent variable and measuring one dependent variable.

A student was measuring the height of plants grown with different types of fertilizer or with plain water. He took his measurements using inches, then realized that he needed to use metric units, so he converted his measurements from inches to centimeters. What is the independent variable in this experiment?

what the plant was watered with Independent variables are variables that scientists select to change within the experiment like different types of fertilizer. Dependent variables are variables that scientists observe in relationship to the independent variable like plant height.