Procedures

Part 1: (approx. 90 minutes)

1. Students should brainstorm factors that seeds need to germinate (external factors). List on the board. Discuss why each of these factors are important.
2. Ask students to describe what it means for a seed to be dormant. Define. Ask students to describe some things that may cause a seed to stay dormant (Optional: Don't discuss internal factors yet).
3. Ask if anyone knows what seed scarification is and then define. Ask students if they think this will effect seed germination. How? Discuss.
4. Ask students if it would be possible to do an experiment to test the effects of artificial scarification on seeds. How could this be done?.
5. Divide students into groups of 2 to 4. Give each group their sets of seeds. Each group will together form a hypothesis to answer the question, "How does artificial seed scarification effect seed germination?" The students will then start writing their lab paper in scientific method form (on their own paper). Students will add to their paper as they complete more of the experiment.
6. Next, the students will gather the materials necessary to set up the experiment.
7. Discuss the variables and the controls so that everyone understands why the experiment is being set up the way it is. Everyone will use the same size containers, same type of light source, same type of soil, and the same planting technique.
8. The students will scarify three of each set of the six seeds using the nail clippers or file (Sand paper can be used in place of the file).
9. The students will then measure the amount of soil that will be used so that it will be the same for each container by using the balance or scale.
10. The students should place the soil in each container and make a hole for each seed that is 2 cm deep (Students can measure 2 cm from the eraser end of a pencil and make a mark on the pencil. Then, they can use the pencil to make the holes the exact depth).
11. Next, the students will plant the scarified seeds in one container and the non-scarified seeds in another container for each group of seeds. The students must be sure to label the containers.
12. Next, the students should water each container with the same amount of water until water starts to drip from the bottom of the container (Be sure to have something under the containers to catch the water).
13. Students should set up a data journal to keep track of the amount of water and soil used. This data table should also be used to keep track of future plant maintenance and observations for each container.

Part 2: Daily Observations

1. The students will check on their plants and record their observations in their data journals each day that we have class for the next two to three weeks. Keep track of which plants sprout first from each container. Record the amount watered each time.
2. Meanwhile, students should be researching to find out information about their two types of plants. Students should find out if the plant is a tree or small plant. Students should find out if the plant has any economic value, where the plants grow, and what times of year it produces its seeds. This research should be done on their own.
3. After one week for most plants, the height of each plant that came up can be measured and recorded. Then record the growth of each plant every one to two days there after using the metric ruler.

Part 3 Drawing Conclusions (approx. 90 minutes)

1. After two to three weeks have elapsed, the students will draw conclusions based on their observations. The students will present their results to the class. The students will also make graphs of collected data.
2. The students should make hypotheses as to why certain plants that were not scarified did not germinate. Students will do some research about their seeds that did not germinate and look further into causes of dormancy.
3. The students will report their findings to the class.
4. The students will compare and contrast the seed coats of their two sets of seeds.
5. The class will discuss internal factors that effect seed dormancy and will make an educated guess as to why the seeds that were not scarified did not germinate.
6. The students will complete their lab papers and graphs. Students will summarize the experiment.