Nature Notes from Common Ground
Week of November 2, 2020
Weekly Nature Note
What's happening in nature this week?
The First Freeze - (note that this was written by Tim last Thursday, before the cold of the weekend)
It is a bittersweet time in the garden. As I write this, we are expecting the first freeze this weekend. In the gardening world, a freeze occurs when the temperature of the air drops below 32 degrees Fahrenheit for long enough that ice crystals form inside the cells of plants. This causes the cell walls to burst, so that when the plant thaws, the fluids inside the cells leak out and make the plant wilted and mushy. The amount of damage depends on how cold it is and for how long.
A frost, different from a freeze, occurs when the surface of the plant gets cold enough for ice crystals to form on the outside of the plants. Sometimes, this can even occur while the air temperature is above freezing. A light frost won’t necessarily kill a plant, though it may cause some leaf damage. For a more in-depth explanation of the difference between a frost and a freeze, as well as tips for protecting plants, check out this article.
This weekend I anticipate a killing freeze. By the time you read this, I imagine all my lovely basil plants will have turned black and wilty from the cold. That’s the bitter part. The sweet part is that, while I may lose some of my most tender garden plants, I’m expecting the flavor of my kale and collards to improve! Kale and collards respond to colder temperatures by increasing the levels of sugars in their leaves. The additional sugar acts like an antifreeze, preventing the formation of ice crystals inside the cells. So while I may lose my basil, my kale will suddenly become much sweeter!
Nature activity of the week
In the nature note above, Tim talked about how kale and collards protect themselves from freezing by increasing the sugar in their leaves. In this activity, we’ll find out how that works!
Materials: Sugar, water, two paper cups (you could also use an ice cube tray), optional timer
Label one cup, “sugar,” and the other cup, “plain.”
Pour the same amount of water into each cup (say, one inch or so - it doesn't matter exactly how much, what matters is that they are both the same)
Put a spoonful or two of sugar into the “sugar” cup and stir until it dissolves.
Place both cups into the freezer.
After 15 minutes, take the two cups out of the freezer and observe.
Return them to the freezer and take out again after another 15 minutes and observe.
Continue until one cup of water is frozen.
Which cup froze first? Do you think if you left it in for longer the other one would freeze too? What does this tell you about sugar, kale leaves, and freezing?
You could also leave your two cups outside overnight on a below-freezing night - does one cup have enough "antifreeze" to keep it from freezing?
Using our senses: The sound of crunching leaves
With all the wind we’ve had lately, most of the leaves are off the trees. One of my favorite things about fall is the sound of my feet walking through fallen leaves. Crunch, crunch, crackle, crunch. Walk in a few different places - do the leaves sound different? Why do you think that is? Try stomping down on the leaves versus shuffling through them. Get a group together and create a (socially-distanced) leaf symphony!
KidsGardening offers some ideas to sneak in some math practice for your young learner in the garden!
Hike of the Week
About this series
In this time of virtual learning and social distancing, we seek to support teachers and families in getting outside in safe and healthy ways. We hope this series provides content and activities to help your students or your family engage in nature-based learning, whether you are learning in person or virtually.
Some of the funding we rely on to keep Nature Notes free comes from the Robert F. Schumann Foundation and The Claire C. Bennitt Watershed Fund, established by the South Central CT Regional Water Authority.
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