All Science Fair Projects

The Effect of Magnets on the Growth of Radish Seedlings

Created by Laura L.

Sixth Grade SOAR 1998

PURPOSE

The purpose of this experiment is to determine whether magnets have an effect on the growth of radish seedlings.

I became interested in the study of the effect magnets, when I discovered that magnets could make you heal faster. Later I decided that that it would be a better idea to study the effect of magnets on plants to keep it a safe experiment.

The information gained from this experiment may be used to help gardeners growing radishes or other plants.

HYPOTHESIS

My hypothesis is that the stem of each plant will be attracted to the magnet. I think that the magnet will pull the plant's root causing it to grow away from the magnet.

I base my hypothesis on my research that states that plants have different kinds of tropisms that attract to different things and cause the plant’s roots to grow downward. I also based it on the fact that magnets attract to some things and repel to other things.

EXPERIMENT DESIGN

The constants in this study are:

How much water the plant receives

How much soil is in the pot

How much light the plant receives

What the growing temperature is

When the seed is planted

How many seeds are planted in each pot

Where each seed is planted

How deep each seed is planted

How big the pot is

How far from the light the pot is

The temperature of the water

What time the light is turned off and on

The manipulated variable is whether a magnet is being used and where the magnet is placed.

The responding variable is whether the plant’s stem and root grow toward the magnet, or away from the magnet.

To measure the responding variable I measure how far the plant grows away from vertical.

MATERIALS

3 clay pots

1 light reflector

2 permanent magnets

1 bag of potting soil

18 radish seeds

1 grow light

1 carpenters level

1 measuring cup

PROCEDURES

1. Gather three of the same size clay pots and label them A, B, and C.

2. In pot A place a permanent magnet in the center of the bottom of the pot.

3. In all three of the pots, pour one liter of potting soil.

4. In all three of the pots poke six, three-centimeter holes in a circular shape around the middle of the pot spaced four centimeters apart.

5. Place one radish seed in each hole.

6. Cover the holes with soil.

7. In pot B place a permanent magnet on top of the potting soil in the middle of the pot.

8. Place no magnets in pot C.

9. Place the three pots in a triangular shape.

10. Place a light reflector 0.7 meters over the plants with a grow lamp in it.

11. Water the plants 100-ml each day.

12. Turn the light off at 8 p.m. on at 7 a.m. each day.

13. Wait until the plant sprouts reach the height of 8 cm.

14. Carefully using a carpenter’s level measure how far from vertical the plant stem has grown.

15. Gently remove the plants from the soil.

16. Determine whether or not the magnet has any effect on the plant's roots by measuring how far they are curved away from the stem.

RESEARCH REPORT

INTRODUCTION

My project examines the effect of magnets have on radish seedlings. In this experiment I hope to find out how a plant reacts to a magnet. I’m going to determine this by measuring the distance the plant grows away from vertical.

I’m going to plant the seeds and wait for them to sprout radishes. When they have, I am going to gently remove the plants from the soil and measure how far away from vertical they have grown, using a carpenters level to detect vertical. I hope to find out if the magnet that I put in the pots affected the way the plants grew. I will determine this by comparing them with the plants in the pot with no magnet.

Plants

There are more than 285,000 different species of plants. Plants unlike other living things make their own food. All seed plants have roots, a stem, and leaves.

Roots

Roots anchor the plant into the ground. Without the root the plant would blow away. Roots help feed the plant by sucking up water and minerals from the soil.

Stems

Stems support the leaves and connect other parts of the plant to the root. Food, water and minerals move through the stem.

There are two types of plant stems, herbaceous and woody. Herbaceous stems are soft, green and flexible. Woody stems are usually not green; trees and shrubs have woody stems.

Most stems grow above the ground but some, called rhizomes, grow underground.

Leaves

Leaves produce food for the plant. In the leaves are tiny openings called stomata. There are about 9,000 to 72,000 stomata per square centimeter of surface area.

Photosynthesis happens when the sunlight hits the leaves. This makes the leaves a very important part of making food for the plant.

Food and energy

Plants make their own food because they have chlorophyll. Photosynthesis is the chemical change that produces food for the plant. In photosynthesis, carbon dioxide, gas and water are mixed to make sugar and oxygen. Sunlight is the energy it needs for the chemical reaction.

Plant Behavior

Because of the earth’s gravity, the roots grow down and the stem grows up. The gravity is a stimulus. Geotropism is the plant’s way of responding. The roots going downward are positive because they are going toward the stimuli. The stem is negative because it is moving away from the stimulus. Plants grow at a slow rate toward their stimuli. When the plant grows toward the sun its called phototropism. The stem is what grows toward the sunlight. Chemical compounds called auxins control tropisms. One kind of auxins make growth cells. If one side of the plant is lighted then the auxins move away from that side. That makes the plant grow more on the shaded side and the unequal mass makes the plant bend toward the sun.

Soil

The first layer of soil is called topsoil. It contains tiny rocks and many kinds of microbes. There are millions of microbes in loam soil, a mixture of clay and sand. About 15 percent of loam is fertile. Fertile soils have a lot of humus and minerals that plants need. Fertilizers are substances added to enrich soil making it better for the plant. Organic fertilizers have plant and animal items, like decayed leaves and manure. Ingredients like these are put in to hold the minerals.

Magnets

A magnet is a metal that attracts metals such as iron and other materials. A magnet has a north pole and a south pole. A north side will attract to a south side but a north and north or south and south side will push away from each other.

A magnet creates a magnetic field: the area around a magnet where magnetic forces can be found. Some things become magnetized when they are in a magnetic field.

There are two different types of magnets, permanent magnets and electromagnets. Permanent magnets hold their magnetic force for a long time. Bar magnets and horseshoe magnets are an example of permanent magnets.

Electric currents flowing through wire can also cause magnetic fields.

 This is called electromagnets. If the battery isn’t plugged in then the flow stops. Electromagnets also have north and south poles. The force of the electromagnet depends on the number of turns in the coil and force of current. When an iron rod is placed inside the coil of an electromagnet the force becomes more powerful.

SUMMARY OF PLANTS

There are more than 285,000 different kinds of plants. One part of the plant is the stem. Water and minerals travel through the stem to get to the leaves and other parts of the plant. The leaves produce food for the plant during photosynthesis.

Plants respond to the earth’s gravity by growing up or down. The plant’s way of responding is called geotropism. The stem growing up is a negative response because it’s growing against the earth’s gravity and the roots growing down are a positive response because they are going with the earth’s gravity which is the stimulus.

SUMMARY OF MAGNETS

A magnet is a piece of metal that attracts iron and certain other materials. It has a north and a south pole. A north pole attracts to a south pole but a north pole repels to a north pole and a south pole repels to a south pole.

A magnet creates a magnetic field around it. When some things are placed inside a magnetic field they become magnetized.

There are two kinds of magnets, permanent magnets and electromagnets.

RESULTS

The original purpose of this experiment was to determine whether or not magnets have an effect on the growth of radish seedlings.

The results of the experiment were: Magnets do have an effect on the growth of radish seedlings, but I can’t show this in my graphs because of the method I used to measure them. When I pulled the plants I could see that the magnet had affected the plants because they were all facing the middle where the magnet was placed. But since I measured how far away from vertical the plants had grown I couldn’t show the accurate results in my graph. All the plants grew away from vertical about the same amount. Even though the plants were facing the middle in the pot in which the magnet was placed at the top, my method of measuring the responding variable didn’t show this. Instead, it showed that the plants had moved away from vertical not that they were bent toward the magnet. So really, yes, the magnet did have an effect on the plants but I just couldn’t show this due to my measuring procedure.

The magnets did have an effect on the stems of the plants but not so much the roots. The roots didn’t change significantly from pot A and B to pot C.

Plant Deflection Measured in Millimeters

CONCLUSION

My hypothesis was that the plant would be attracted to the magnet. I thought that the magnet would pull the plant's root causing it to grow away from vertical. I thought that both the stem and the roots would show tropism toward the magnet.

The results of this experiment show that The plants did attract to the magnet but because of my method of measuring the responding variable it was difficult to show the effect on the plants. I know that the magnet had an effect on the plants because I could see that the plants were bending toward the middle of the pot.

I made a conclusion that the plants in pot C would grow straight up but instead they grew in all directions. So when I measured how far away from vertical I wasn’t determining whether or not it grew toward the magnet just away from vertical.

By looking at the results of my experiment I would have to say my hypothesis is rejected because I’m not sure if it was the tropisms that attracted to the magnet or something else. Although the stems did attract to the magnet in pot A, the roots did not as I stated in my hypothesis.

Because of the results of this experiment, I wonder why a radish plant attracts to a magnet and if it attracts to other kinds of plants.

If I were to conduct this project again I would probably choose to use larger pots, because I feel that the plants could have been stronger if they were in a bigger pot. I also would have used a method that involved measuring how far toward the middle they grew instead of away from vertical because they all were away from vertical in some direction or another. But in the pots in which there were magnets, the roots or stem tended to grow toward the magnet. But since my method did not involve a way of measuring in which direction the plant grew, I don’t have a way of determining that. I just feel that if I would have used different method of measuring the responding variable then maybe I would have more accurate results.

BIBLIOGRAPHY

Heilmler, Charles and Price, Jack Physical Science Columbus, Ohio, Merrill, 198

Heilmler, Charles Focus on Life Science Columbus, Ohio, Merrill, 1984.

"Plants," World Book Encyclopedia, 1995.

"Magnets," World Book Encyclopedia, 1995.

Vacchone, Glen Magnet Science New York, New York, Sterling Publishing Co. Inc., 1995.

Appendix

Photosynthesis - The process by which chlorophyll containing cells in green plants use the energy of light to synthesize carbohydrates from carbon dioxide.

electromagnet - A device consisting essentially of a soft-iron core wound with a current-carrying coil of uninsulated wire.

permanent magnet - A magnet that can hold its force for a long time.

magnetized - To make magnetic.

stimulus - Something that stimulates; incentive of spur.

magnetic field - A region of space, as that around a magnet or an electric current, in which a detectable force is exerted on a magnetic body at any point.

organic fertilizers - Using or grown with fertilizers consisting only of natural animal or vegetable matter.

Chlorophyll - A green plant pigment essential in photosynthesis essential in photosynthesis.

auxins - A plant hormone that promotes growth.