Measuring Germination Rates

Introduction

Have you ever wondered what happens to a seed when it is placed in the ground? Do you think seeds grow quickly or slowly? Do you think weather has any effect on how seeds grow? This experiment will allow you to see what seeds do under ground, and how temperature affects what they do.

You can do this experiment as a whole group, or in small groups which would allow you to compare your data with each other.

Materials

• Two Petri dishes or similar dishes with covers or small, clear plastic ziplock baggies
• Paper towel or filter paper
• Seeds (lentils or kidney seeds), 30 seeds per dish
• Two classroom thermometers
• Student Data Sheet
• Spreadsheet software on a computer

Procedure

1. Place the filter paper or paper towel inside the dishes or bags
2. Moisten the paper until there is a tiny bit of standing water
3. Place 30 seeds on top of the wet paper in each dish. Space them as evenly as possible.
4. Put the covers on the dishes or ziplock the bags.
5. Place one of the dishes/bags in a warm place and the other one in a cool place.
6. Place a thermometer next to each dish and record the temperatures.
7. Check both dishes every other day and record the following data:
• a) the Temperature
• b) the Number of Seeds that have Germinated
• c) anything you observe about the seeds and the containers, such as mold growing or seeds changing colors
8. After recording the data, remove the seeds that have germinated. You can plant them in paper cups or in a garden.
9. If the paper filter or towel dries out, rewet it just a little. This time, don't leave water standing in the container.
10. Continue this process for three weeks or until your teacher tells you to stop.

Data Collection

Collect your data on a schedule. One suggestion is to record on Monday, Wednesday, and Friday. The day you start the experiment is Day 1. Be sure to number your days correctly. If you start on a Monday and make your first record on Wednesday, your data sheet should start with Day 3. If you are unsure how to number your data collection days, ask your teacher.

Here are the things to record on the day you start the experiment:

• Date and Time seeds were placed in containers
• Types of seeds you are using
• Number of seeds in each container
• Location of the two containers
• Temperature of each location
• A drawing or written description of the process followed on Day 1

Record the following every other day:

• Date and Time
• Temperature of each location
• Number of seeds that have germinated
• Number of hours of light on each container
• Description of each container and a drawing of it

Graphing the data

In order to make a spreadsheet of your data, follow the instructions on the Creating a Spreadsheet page. If you are not using a computer program, construct a graph of how many seeds germinated in each location on paper. Use the sample on the Creating a Paper Graph page.

Questions

Discuss with your classmates what is happening. Here are some questions to get you started:

• How does the temperature effect the seeds?
• How many seeds are germinating each day?
• How does this experiment relate to the weather's effect on seeds?
• Will this experiement work for different types of seeds?
• What might happen if the temperature suddenly changed in one or both locations?
• What might happen if too much water were added? Not enough water?
• How would the presence of insects or worms affect the growth of the seeds?

Now think of five or more questions to ask each other and discuss the possible answers.

Extension

After collecting and graphing your data, you should be able to do the advanced calculations to show the following information:

• the average temperature for each germination location
• the number of days that passed until the first seed germinated
• the number of days between the first seed germination and the last seed germination
• Total number of seeds that germinated
• Total percentage of seeds germinated

Publish

Print out copies of your spreadsheets, charts, and graphs. Display them on a bulletin board or other area. Make sure to include the written descriptions of what you did and how you collected your data so that others can recreate your experiment. Try another form of presenting your findings to the class by using Presentation Methods and Ideas.