Radiant Radish Seeds

Related Links

• Science Fair Project Guide

Project Summary

Difficulty	3
Time required	Average (about one week)
Prerequisites	None
Material Availability	Readily available
Cost	Very Low (under $20)
Safety	Requires adult supervision

Donate to Science Buddies

Sponsor

Sponsored by a generous grant from Monsanto Fund

Objective

To determine the effect of radiation and heat on the germination of radish seeds.

Introduction

You might already know that if you plant a seed it will grow into a plant. But did you know that inside of every seed is a baby plant? The inside of a plant seed has three main parts: the embryo is the baby plant, the endosperm is food for the baby plant, and the cotyledon(s), which look like leaves and contain the endosperm. All of the parts of the baby plant are enclosed and protected by a special covering called the seed coat. The seed coat protects the baby plant embryo from many different conditions, some of these conditions can be: drying out, freezing temperatures, heat, radiation, or acidity.

Some seeds have very large and tough seed coats while others have very weak and fragile seed coats. This is because different kinds of plants have adapted to different environments, and so need to be protected from different things. Desert plants need protection from drought, arctic plants need to be protected from cold winter temperatures, and plants from pine forests often need protection from forest fire. In fact, seeds from some forest plants need a forest fire before they can sprout through their tough, protective seed coats!

Seed sprouting is called germination, and is the process during which the baby plant emerges from the seed and develops its first set of true leaves. Germination begins when the seed absorbs water, which causes the endosperm to swell and pop open the seed coat. Then the embryo will grow and develop its first set of true leaves, using food stored in the endosperm for energy. Some seeds take a very long time to germinate, while others germinate very quickly. For this experiment, we have chosen radish seeds, which germinate very quickly in 3 to 5 days.

Plants use energy from the sun to grow and make food in their leaves. Some of the sun's energy is in the form of ultraviolet radiation, sometimes called UV rays. The UV radiation from the sun is one kind of electromagnetic radiation. Electromagnetic radiation is also produced by many household appliances, like radios, cell phones, televisions, and your microwave. When you use a microwave, the microwaves travel through your food, causing the food to cook. In this experiment we will use a microwave to expose our seeds to electromagnetic radiation. Sometimes electromagnetic energy can also cause heat, and in our experiment we will heat our seeds by baking them in the oven.

Terms, Concepts and Questions to Start Background Research

To do this type of experiment you should know what the following terms mean. Have an adult help you search the internet, or take you to your local library to find out more!

• seed
• seed coat
• embryo
• sprout
• germinate
• heat
• temperature

Bibliography

• Visit the website of "The Great Plant Escape" to help Detective Le Plant solve 6 cases, learn about plants, use the glossary to learn new terms and see pictures of plant parts:
  Stack, Greg, et. al. 2005. "The Great Plant Escape." University of Illinois, Urbana-Champaign. [12/13/05]
  http://www.urbanext.uiuc.edu/gpe/index.html
  
• Gibbons, Gail. 1991. "From Seed to Plant." New York, NY: Holiday House.
• Rockwell, Anne. 1998. "One Bean." New York, NY: Walker & Company.

Materials and Equipment

• radish seeds
• oven (you will needs your parents supervision)
• microwave
• napkins
• permanent marker
• aluminum foil
• tape
• Zip-Lock baggies
• water and a dropper
• a sunny window

Experimental Procedure

1. Before you start, have an adult preheat the oven to 250 degrees.
2. Now you can start to set up your experiments. To set up for each experiment, you will need to do a lot of labeling and organizing, so that your seeds won't get mixed up with each other. To do this you can label each zip lock baggie with a permanent marker.
3. You will need to label one baggie for your "control" group, one baggie for each group of microwaved seeds, and one baggie for each group of baked seeds. Label each microwaved seed baggie with "MW" and the time you microwaved your seeds: "5 seconds," "10 seconds," "20 seconds," etc. Label each baked seed baggie with "B" and the time you baked your seeds: "10 minutes," "20 minutes," "30 minutes," etc.
4. Now you are ready to turn each baggie into a miniature greenhouse. Place a folded napkin in the bottom of each baggie making sure it lies nice and flat.
5. Add a few drops of water into each baggie until the napkin is evenly moist, but not dripping wet. Keep the baggies ready, so that as you treat your seeds you can put them inside the baggies, zip the baggie closed, and tape it to a sunny window.
6. One more important thing to do is to set up a "control" group. This group of seeds will not be microwaved or baked in the oven. The reason for having a control group is so that you know your seeds are good and can sprout. What if the seeds you bought are bad? For this group, take the bag labeled "control" and add 10 radish seeds to the bottom of the bag on one side of the napkin, close the baggie and tape to the window.

7. For the microwave experiment, you will be taking groups of 10 seeds and microwaving them for different amounts of time. Count out 10 radish seeds, place on a dry napkin, and microwave for a period of time (5, 10, 15, or 20 seconds).
8. Place the seeds into the matching bag with the correct label, close the bag, and tape it to the window.
9. For the baked seeds you will need your parents help—remember the oven will be very hot! Make some little squares of aluminum foil and fold up the outer edges to put your seeds into.
10. Place each little tin on a cookie sheet and fill with 10 seeds.
11. Place the entire cookie sheet onto the oven, which has been preheated to 250 degrees.
12. Take out a group of seeds about every 10 minutes, so that the time in the oven will match the time on each baggie.
13. Place the seeds into the matching bag with the correct label, close the bag, and tape it to the window.
14. Let all of your experiments sit taped to the window for 3 to 5 days. After that time you will notice that some of the seeds have sprouted. Do not open the bags or add water during this time, if they were sealed properly they will not dry out or run out of air.
15. After the seeds have sprouted, write the number of sprouted and un-sprouted seeds on the baggie for each group. Record your data in a table, here is an example of how to make a table:

    Group	Time Treated	Number Sprouted	Number Un-sprouted
    Control	none
    Microwaved	10 seconds
    Microwaved	20 seconds
    Baked	10 minutes
    Baked	20 minutes
    Etc.	Etc.

16. After you have finished counting up all of your seeds and sprouts, you are ready to make a graph. There are many different types of graphs you can use for this experiment. The simplest type of graph will be a bar graph. On the left side of your graph, called the Y-axis, you will put the number of seeds sprouted from 1 to 10. On the bottom of the graph you will put your different groups. Draw a bar for each group that indicates how many seeds sprouted for that group.

17. From your graph, you can compare the seeds from your different experiments to your control seeds. Do more seeds sprout, or less seeds sprout in your experiments? What do you think happens when the seeds are exposed to microwaves? What do you think happens when the seeds are heated? What does this tell you about seeds?

Variations

• Think about temperature in your seed experiment. Do you think all of the seeds were heated to the same temperature? Is the temperature of the oven the same as the temperature of the microwave? You can calculate the actual temperature the seeds were exposed to in the microwave by heating up a cup of water and measuring the starting and final temperature using a candy thermometer. You can measure the accuracy of your oven temperature by using an oven thermometer. How did the temperature of the microwaved seeds compare to the baked seeds? Was one method hotter than the other? How did the temperature change as more time was added? Could you use this new information to adjust the treatment times in your original experiment?
• You can try the same experiments on different types of seeds. Do different plant species have seeds that are more tolerant to these conditions?
• You can also try experiments with more conditions. For example, acidity can be a problem for some seeds, but good for others. You can use vinegar to test the effects of acid by mixing with the water you use to keep your seeds moist.
• Did you know that some seeds sprout better in the dark? You can try different types of seeds in the light and in the dark to see which conditions are best for each type of seed.
• Here is an amazing seed fact: Ancient seeds have been found by scientists frozen deep in arctic ice, and when scientists tried to grow these seeds they sprouted! Try this experiment yourself by putting some seeds in the freezer.

• For more science project ideas in this area of science, see Plant Biology Project Ideas

Join Science Buddies

Credits

Sara Agee, Ph.D., Science Buddies

Last edit date: 2006-01-18 17:25:11

If this website has helped you, won't you consider a small gift so we may continue developing resources to help teachers and students?