Radish Seed Lab!Name ______Hr. ___

Thanks to: for ideas and information

REES- Biology

Objectives:

  1. To identify characteristics that distinguishes living organisms from non-living objects.
  2. To propose and predict the factors that may affect the rate of germination in the Radish seeds.
  3. To design and perform an experiment in which correct scientific method is used.

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.

Reading check: What are the 3 parts of a plant seed? ______

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!

Reading check: What is one advantage for pine trees in a mountainous area to have a very tough outside seed covering? ______

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.

Reading check: Write out (summarize) the 2 steps of germination. ______

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.

Reading check: What type of radiation makes your cell phone work? ______

Terms, Concepts and Questions to Start Background Research

To do this type of experiment you should know what the following terms mean. Find their definitions and write them out below. You may also draw a picture and label it if that helps you remember what each term means.

  • seed coat (testa)-
  • shoot (plumule)-
  • germinate-
  • cotyledon-
  • root (radicle)-

Let’s Experiment!

Materials and Equipment

  • radish seeds
  • oven
  • microwave
  • napkins
  • permanent marker
  • aluminum foil
  • tape
  • Zip-Lock baggies
  • water and a dropper
  • a sunny window or grow lamps

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: "10 seconds," "20 seconds," "30 seconds,” Label each baked seed baggie with "B" and the time you baked your seeds: "10 minutes," "20 minutes," "30 minutes,". (We will actually do this as a class; each table will have one of these bags assigned to them.)
  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.
  1. 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 (10, 20, or 30 seconds).
  2. Place the seeds into the matching bag with the correct label, close the bag, and place it under the grow light.
  3. For the baked seeds—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.
  4. Place each little tin on a cookie sheet and fill with 10 seeds.
  5. Place the entire cookie sheet onto the oven, which has been preheated to 250 degrees.
  6. Take out a group of seeds about every 10 minutes, so that the time in the oven will match the time on each baggie.
  7. Place the seeds into the matching bag with the correct label, close the bag, and place it under the grow light.
  8. Let all of your experiments sit under the grow light 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.
  9. After the seeds have sprouted, write the number of sprouted and un-sprouted seeds on the baggie for each group. Record your data in this table:

Group / Time Treated / Number Sprouted / Number Un-sprouted
Control (MW) / none
Control (B) / none
Microwaved / 10 seconds
Microwaved / 20 seconds
Microwaved / 30 minutes
Baked / 10 minutes
Baked / 20 minutes
Baked / 30 minutes
  1. 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.
  1. 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?