Understanding Microclimates: A Matter of Degrees
This fall, you are planting a Journey North Tulip Garden so you can proclaim the official arrival of spring in your community. Students across North America are depending on you! You must find a place that accurately represents the general climate of your region. Otherwise your tulips will not be a true indicator of spring's arrival.
Watch out for microclimates! (Do you know a microclimate when you see one?) In this lesson students will learn to recognize the variables that can create a microclimate. Then they will measure one of these variables, temperature. Finally, they'll determine whether temperatures in their selected garden site accurately reflect the official temperatures of your town.
1. As an introduction to this activity, have students review the planting instructions.
Have the class make a list of all the variables we are attempting to control in this experiment.
2. Discuss and define the word "microclimate".
Have students brainstorm as to what this word might mean. Find a definition the class can agree upon. Then verify the definition with a dictionary or local resource.
A microclimate is the climate of a small, localized area in which the climate differs from the general climate due to the unique amounts of sunlight, wind and moisture this localized area receives.
Microclimates can occur in localized areas due to nearby:
- Man-made features (buildings, parking lots, roads),
- Geographical features (mountains, oceans, lakes) and
- Biological features (forests, prairies, croplands).
3. Can you find different microclimates on your school grounds?
Which of the above features might create a microclimate at your school? Take students outdoors to look for places that might have a microclimate. For example, look for places that are shady due to a nearby building. Can you find places that always remain in the shade? How might wind affect growing conditions? Are there places which are always protected from the wind? When it rains, where does the water go? Can you find large areas that are paved? How might this affect moisture conditions of the soil nearby? Can you find places that never receive rain? Etc.
4. Measure the temperatures differences at various places around your school grounds.
Have students draw a map of your school building and surrounding grounds. Ask students if they think the temperature will be the same everywhere on the map? First have them predict temperatures, then go outside and see what they find:
- What's the warmest place? Why do you think it's so warm?
- What's the coolest place you can find? What do you think makes it so cool?
- Do you think these temperature differences will change over the course of a day?
- Where did temperatures differ the most from what you predicted?
4. Compare your school's varying temperatures with today's official temperature.
When we pick up the newspaper we're told the temperature of our city. However, as you've just discovered, temperatures vary considerably depending on location. What's the official temperature in your town today? How do the temperature readings you found at your school compare with the official reading?
Be careful not to confuse the predicted temperature given in a forecast with the day's actual temperature. Most newspapers report the previous day's temperatures, but in small print. Also, note that only the day's high and low temperatures are reported. Therefore, you should attempt to conduct your experiment at the warmest time of the day, usually between 2-3 pm.
6. Home Sweet Home
Based on your microclimate study, where is the best place for your garden?
Print out the temperature chart. Periodically, go outside and measure the high temperatures in the place you've selected for your garden. Record daily the daily high and low temperatures that are published in your newspaper on the chart. Compare these temperatures with your garden site's temperatures.
- Are temperatures in your garden generally warmer or cooler than the temperatures reported in the newspaper?
- If different, by how many degrees do they vary? Why do you think this is true?
As a class, discuss whether you think your tulips will bloom "at the right time" for your region if planted at this site.
A Final Note
We recognize that you may have very few options available for a planting site. Therefore, if you are simply unable to plant your garden in a open area, please be sure to mention this next spring when you report from your site. Describe the microclimate of your garden, and explain why you think this has affected your results.
Also, make sure students understand the affect a microclimate can have on plant growth. This will help them interpret the results they receive from other gardens next spring, as well as the results from their own garden.