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# Introduction to laboratory techniques

## on Jul 20, 2011

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Introduction to laboratory techniques

Introduction to laboratory techniques

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## Introduction to laboratory techniquesPresentation Transcript

• Unit 1: Introduction to Laboratory Techniques
1.5 Data Tables and Graphs
• Data tables and graphs
Why are tables and graphs important is science?
• Data tables and graphs
Making data tables and graphs are useful tools for both recording and communicating scientific data.
• Data tables and graphs
• Making data tables
You can use a data table to organize and record the measurements that you make .
Some examples of information that might be recorded in data tables are frequencies, times, and amounts.
• Making data tables
Example:
Suppose you are investigating photosynthesis in two elodea plants. One sits in direct sunlight, and the other sits in a dimly lit room. You measure the rate of photosynthesis by counting the number of bubbles in the jar every ten minutes.
How would you make a table to organize and record the data you collect?
• Making data tables
1. Title and number you data.
2. Decide how you will organize the table into columns and rows.
3. Any units, such as seconds or degrees, should de included in column headings, not in the individual cells.
• Making data tables
Table 1. Number of Bubbles form Elodea
• Making data tables
The data in the table could also be organized in a different way.
How?
• Making data tables
Table 1. Number of Bubbles form Elodea
• Home work
Observing the parts of flowers
Process Skills:
Observing
Collecting and interpreting data
Inferring
Materials:
Plastic knife
Newspaper
Hand lens
2 different flowers
• Home work
Procedure:
1. Collect two different types of flowers from your garden or neighborhood.
2. Spread newspapers on the floor.
3. Collect the following data: number of sepals, color of sepals, number of petals, color of petals, number of stamens, number of pistils, drawing of stamen, drawing of pistil.
4. Record the information collected on a table.
• Home work
Explain how the parts of the two flower s are similar and different.
What might you infer about the parts of other flowers with four parts? How might they be similar to these flower parts? How might they be different?
*Present your homework in the form of a lab report. The questions and answers should be included as your conclusion. In this report you do not need to include a hypothesis nor an introduction.
• Home work
• Bar Graph
A bar graph is a type of graph in which the lengths of the bars are used to represent and compare data.
A numerical scale is used to determine the length of the bars.
• Bar Graph
Example:
To determine the effect of water on seed sprouting, three cups were filled with sand, and ten seeds were planted in each. Different amounts of water were added to each cup over a three-day period.
• Bar Graph
Table 1. Effect of Water on Seed Sprouting
• Bar Graph
Choose a numerical scale. The greatest value is 8, so the end of the scale should have a value greater that 8, such as 10.
Draw and label the axes. Mark intervals on the vertical axis according to the scale you chose.
Draw a bar for each data value. Use the scale to decide how long to make each bar.
• Be sure to add a number and a title
Figure 1. Effect of Water on Seed Sprouting
Number of sprouting seeds
Label each bar
0 10 20
Label the scale
• Double Bar Graph
A double bar graph is a bar graph that shows two sets of data.
The two bars for each measurement are drawn next to each other.
• Double Bar Graph
Example:
The seed-sprouting experiment was done using both sand and potting soil. The data for sand and potting soil can be plotted on one graph.
Draw one set of bars, using the data for sand, as shown below.
Draw bars for the potting-soil data next to the bars for the sand data. Shade them a different color. Add a key.
• Double Bar Graph
Table 2. Effect of Water and Soil on Seed Sprouting
• Figure2. Effect of Water and Soil on Seed Sprouting
Make key to show what each color represents
Number of sprouting seeds
Leave room for “potting –soil” bars.
0 10 20
• Class work
Practice collecting and interpreting data.
Materials:
Pencil
Ruler
Paper
• Class work
Procedure:
Make a chart to record how many of your classmates have blue eyes, brown eyes, black eyes or green eyes.
Make a chart to record how many of your classmates have blonde hair, red hair brown hair or black hair.
Make a chart to record how many of your classmates are 14, 15 or 16 years old.
• Class work
Take a survey to collect the data on hair color, eye color and age. Make a tally mark for each student’s answer in the correct place on the charts. Then calculate the total number of students for each answer.
Draw three bar graphs or a triple bar graph to show your results. Make sure to label the X and Y axes. Use different colors to make a key to distinguish each bar.