Author: Biology Junction Team

Bacteria Worksheet

 

1.

Sample Problems on Bar Graphs

Problem 1:

The following table illustrates the average employee salary at Smith, Inc. for each of the last fifteen years. Mrs. Smith, the general manager of Smith, Inc., has been asked to submit to the local newspaper a bar graph illustrating the average employee salary in her company for each of the last 15 years.

Problem 2:

Your basketball team, the Ricebirds, has been asked to create a bar graph illustrating your team’s scores for each of its last ten games. The following table illustrates these scores.

Problem 3:

Quality Motor Company is claiming that their cars have increased in quality more significantly than the cars of their competitors. They want to use bar graphs showing the average longevity of cars from each company, as well as their own, for each of the last 12 years. Given the following data for the company, create this bar graph.

Problem 4:

You are the manager of the local mall, and you want to express to the public the safety of your mall. Use the following data that has been collected during the past year to make a bar graph.

Metric Measurement Lab

Introduction:

            Every scientific experiment in some way involves measurement.  Scientists worldwide use the metric system to display the results of measurements.  This system simplifies calculations based on a decimal system (powers of ten), opposed to the confusing English system of measurement.  Less confusion and better communication between scientists around the world makes the metric system more efficient than the English system for use in experiments.  The useful prefixes of the metric system are also known as the International System of Units (SI).

            Two measurements explored in this lab are mass and volume.  Mass is represented by grams, while volume is represented by milliliters (liquid) and cubic centimeters (solids with ruler measurement).  The purpose of this investigation is to get acquainted with and be accurate with the metric system.

Hypothesis:

By using a graduated cylinder, mass balance, and metric ruler, mass and volume can be found.  

Materials:

The materials used in this experiment include a graduated cylinder, an eyedropper, and a beaker of water for Part A; 20 ml of water, a graduated cylinder, and three marbles for Part B; a metric ruler, mass balance, three marbles, and a graduated cylinder for Part C; a metric ruler for Part D; and a graduated cylinder, eyedropper, six labeled test tubes, and three 25ml beakers of colored water (one with red, one with blue, and one with yellow) for Part E.  

Methods:

Part A:  Count you drops!

Fill a small graduated cylinder with 10 ml of water.  Count and record the number of drops it takes to raise the water to 11ml.  Leave the water in the graduated cylinder and count and record the number of drops it takes to raise the water to 12ml.  Leave the water in the graduated cylinder and count and record the number of drops it takes to raise the water to 13ml.  Calculate the average number of drops and round to the nearest tenth.

Part B:  Water Displacement

Add 20ml of water to a 100ml graduated cylinder.  Record this amount in the chart.  Add three marbles to the cylinder and measure and record the volume.  Find the difference between the two measurements and record it in the chart.  The difference between the two measurements will be the volume of the three marbles.

Part C:  Mass Mania

Check to see that the Pinter on the balance is pointing to zero.  If it is not, check to see that all the Riders (weights) are all the way to the left at the Zero mark.  Adjust the balance by turning the Adjustment Screw slowly until it points at zero.  Place the metric ruler on the pan and read and record the ruler’s mass.  After resetting the balance to zero, measure and record the mass of the empty 50ml graduated cylinder and then the three marbles.  Reset the balance to zero when all items have been massed. 

Part D:  Volume by Formula

Use the formula Volume=length x width x height to find the volume of the box.  Measure to the nearest centimeter before calculating the answer.  If necessary, round the answer to two decimal places.

Part E:  Color Challenge

Obtain the following items from the teacher:  3 beakers with colored water-25ml of each color (red, blue, and yellow), 1 graduated cylinder (25ml to 50ml), 1 eyedropper, and 6 test tubes labeled A, B, C, D, E, and F.  Perform each of the following steps using accurate measurements.  Measure 17ml of red water from the beaker and po9ur it into test tube A.  Measure 21ml of yellow water from the beaker and pour it into test tube C.  Measure 22ml of blue water from the beaker and pour it into test tube E.  Measure 5ml of water from test tube A and pour it into test tube B.  Measure 6ml of water from test tube C and pour it into test tube D.  Measure 8ml of water from test tube E and pour it into test tube F.  Measure 5ml of water from test tube C and pour it into test tube B.  Measure 2ml of water from test tube A and pour it into test tube F.  Measure 4ml of water from test tube E and pour it into test tube D.  Record the results in the chart.

Results:

Part A:  Count your drops!

1. Take a guess—how many drops of water will it take to equal 1 milliliter?  18 drops.
2. Based on your average, how close were you to your guess?  7 drops off of average.
3. Based on your average, how many drops would it take to make 1 liter?  25,000 drops.

Part B:  Water Displacement

Part C:  Mass Mania

Part D:  Volume by Formula

Volume= length x width x height

7.0 cm x 1.0 cm x 3.0 cm = 21.0 cubic centimeters

Part E:  Color Challenge

Discussion and Conclusion:

By using a graduated cylinder, mass balance, and metric ruler, mass and volume can be found.  The purpose of Part A was to be accurate with reading graduated cylinders and how many drops of water make one milliliter.  This was accomplished by using an eyedropper to count the drops and reading the bottom of the meniscus to see when to stop dropping.  The average was found by adding the number of drops it took to reach the next milliliter (three times repeated) together and dividing by how many times the experiment was repeated which was three times.  (24+26+25)/3=25 average drops.  The purpose of Part B was to use water displacement to find volume.  In this particular experiment, water displacement was used to find the volume of three marbles.  To do this, the volume of the water before adding the marbles (20ml) was subtracted from the volume of the water after adding the marbles (25ml), to get the difference in the two volumes (5ml) which ultimately was the volume of the three marbles (5ml).  25ml-20ml=5ml.  The purpose of part C was to learn to use the balance accurately to determine the mass of an object(s).  To use a balance, the pointer and weights must be set at zero.  The mass of the three marbles, empty graduated cylinder, and metric ruler were found by placing them on the pan of the balance and moving the weights until the pointer was at zero again.  Mass is measured in grams.  The purpose of Part D was to use a metric ruler properly and apply your measurements to a formula to find volume.  To fill in the volume formula, length, width, and height of the box was found in the nearest centimeter with the metric ruler.  After those measurements were found, they had to be multiplied together to find the volume in cubic centimeters.  7cm x 1cm x 3cm=21 cubic cm.  Volume is expressed with cubic centimeter for solids and milliliters for liquids.  The purpose of Part e was to be accurate in liquid measurements to find the color and volume of the six test tubes.  This was accomplished by taking certain amounts of colored water from some beakers of test tubes and adding them to other test tubes.  If something was not measured right, the water in the test tube would not be the correct color.  It is important to always use accurate methods and measurements because details matter in science and experiments.