UV Light Plant Investigation

Study/Challenge: to examine the effects of UV light on germination and growth of plants; investigation of other factors related to germination (as chosen by the students)

Materials:

• we used a UV light garden (if you don't have access to one, you could just use a window sill!)
• soil and water
• seeds (your choice - we used bean seeds)
• plastic baggies
• paper towel
• small gardening shovel or scoop
• other materials such as growing pots, depending on what the students choose to investigate

Safety Notes:

If using a UV garden, be sure to follow the guidelines for usage and teach the students about them also. General safety measures should be followed for the experiments, such as common sense review of handling soil, handling hot water, and use of electrical appliances.

Lesson Plan:

1. Set the Stage: Activate Prior Knowledge by asking students questions like

• What do plants need to grow? (Carbon dioxide/air, water, nutrients (usually through soil), and sunlight (light))
• Have you ever grown plants at your home? What did you grow? Did you grow it indoors or outdoors? How did the plants get all of the things they needed to grow at your home, both inside and outside?
• What do seeds need to start growing? (water, correct temperature (warmth) and good location). Introduce the term - germination.
• Show the students the UV garden. Discuss what the possible advantages are to using this type of garden for germination (warmth, light, moist soil) and what UV light does for plants.
• Introduce the challenge: "We will design experiments to investigate germination. In pairs, small groups, or individually, design an experiment that will show which factors are most important for speeding up the germination of bean seeds."
• Allow students to work on a plan for an experiment. Encourage students to consider the needs of a seed - water, warmth, and location. Once students have planned their experiments, have them share their ideas with the class. See if any experiments are similar, and encourage students to consider working together. Also, encourage them to consider a variety of factors such as the various experiments my class came up with:
  • One seed in UV garden versus one seed in a pot in window sill with same water content
  • One seed in cupboard without light with same water content versus one seed in UV garden
  • One seed fed hot water, one seed fed cold water, and one seed fed room temperature water to see which germinates first
  • One seed in the UV garden under a shade (no UV light) and one in the UV garden without a shade
  • One seed in a baggie hanging on the window with a wet paper towel in it versus one seed in the UV garden

2. Prepare for and conduct the experiments

a) Remind students about using a 'control' in their experiments. (A control seed would be one that has nothing done to it except growing naturally; in this case, our control seeds were one that grew without any changes to it in the UV garden and one control seed that was planted in the same soil but on a window sill, and given the same amount of water each day to keep the soil moist like in the UV garden. That way, we could compare the seeds that had other factors influencing their growth to the 'control' seeds like in proper scientific method.)

b) Set up the 'control' seeds and the experiments using whatever needed supplies (as above).

c) Have students journal the seed and plant growth using quantitative data (measurements) on a graph. They would plot days on the x axis and germination date/height of plant on the y axis. Every day, they need to examine the soil for evidence of germination (a shoot that reaches the surface) and then log down the date as their germination day. It is important to note how many days it takes to germinate as the research out there says that UV light increase germination rate - your students could prove or disprove this! Then the students use a ruler to measure the height of the shoot every day to plot the growth - they will see that some plants double their height in the early days of development - some great discussion could come out of this:

• What if a tree doubled its height every day?
• Why is bamboo considered such a sustainable plant? (fast growth)

d) At the same time as this is going on, students could examine the germination of seeds that were put in baggies with paper towel on the window and identify the parts of the plant as it is growing.

(there are great images of the parts of a seed online to help students with the parts of the early plant, such as the radicle, the cotelydon, plumule, and the epicotyl)

e) Our students shared their learning informally through a class discussion and sharing session. Other options for presentation and assessment could include:

• a visual documentation of their learning through a slide show, poster, or other form of presentation
• a completed graph and a report attached that describes their learning
• video documentation of the growth of the plant using Seesaw, I movie, or other video apps

Extensions:

• Investigate other biodiversity concepts related to what was learned by completing group, pair, or individual research on topics such as the importance of biodiversity in farming practices (versus monoculture), sustainability of bamboo products, comparing the rate of germination of other vegetables and seeds with bean seeds, or researching where everyday items come from, thanks to biodiversity (see Ontario Science Curriculum Biodiversity expectation 3.6). They can present their findings individually, in pairs, or in groups and choose from a variety of presentation media such as Google slides, Prezi, I movie, posters, pamphlets, news articles, or other presentation forms.
• 'The Jack and the Beanstalk Math Investigation': Students can ponder and work out by problem solving if Jack's beanstalk could actually grow to reach the clouds, and how long it would take to do so, if the height of the beanstalk doubled every day! Students can use their own results from measuring their beanstalks to calculate the days needed to reach that height.

Overall Assessment can include Language (for the Extension activity), Science Expectations and Math Expectations:

• Reading: 1.2, 1.4, 1.6, 1.7, 1.8
• Writing: 1.3, 1.4, 1.5, 1.6, 2.1, 2.7, 2.8
• Media: 3.2, 3.4
• Oral and Visual Communication: 2.1, 2.3, 2.4, 2.7
• Science - Biodiversity Expectations: 1.2, 2.3, 2.5, 3.4, 3.6
• Math - estimate, measure, and record quantities, using the metric measurement system; collect and organize discrete or continuous primary data and secondary data and display the data in charts, tables, and graphs (including continuous line graphs) that have appropriate titles, labels (e.g., appropriate units marked on the axes), and scales (e.g., with appropriate increments); collect data by conducting an experiment to do with their environment, and record observations or measurements; read, describe, and interpret data; solve problems using multiplication and division using a variety of strategies; make connections among mathematical concepts and procedures, and relate mathematical ideas to situations drawn from other contexts; develop, select, and apply problem-solving strategies as they pose and solve problems and conduct investigations, to help deepen their mathematical understanding; develop and apply reasoning skills to make and investigate conjectures and construct and defend arguments; communicate mathematical thinking orally, visually, and in writing, using everyday language