Journey North Tulip Garden and Climate Change Study

How Freezing Temperatures Affect Plants

What happens to plants when freezing temperatures hit? Why not set up some cool experiments to explore this question?
(Teachers: See our Teacher Background section for an overview.)

What's going on here?

Photo: David Underhill

What do you think will happen to these plant leaves? Click on the picture to see a larger one.

What did you see?
What do you think caused it?
What do you think will happen next?

Explore This! What Happens When Water Freezes

Did you know that most plants are more than 85% water? Before digging into frozen plants, it helps to examine this familiar liquid. What do you think happens when water freezes? Try this setup:
Materials: two plastic cups or glass jars, some sugar, two pieces of masking tape.

Add water to each cup or jar until it's half full. Put a piece of masking tape around each cup or jar so the water is even with the top of the tape. Next, do this to the containers:
Cup 1: Leave the cup as is.
Cup 2: Add two large teaspoons of sugar. Stir to dissolve it.
Put both containers in the freezer.
Click to download the What Happens When Water Freezes handout. Fill it in.

Discussion and Journaling Questions

Click on this ice crystal to see a larger one. Then ponder the questions on the page with the picture.

Photo: Greg Rob

How did your predictions compare with what actually happened?
What can you conclude about freezing water?
How do you think freezing water might affect plants?
How do you think plants might protect themselves?
Hint: Many plants build up sugars, salts, and other substances before the winter.

Explore This! Freeze Your Own Leaves

Find two leaves to try freezing. One should be from a "hardy" outdoor tree or shrub that keeps its leaves all winter. (If you live where it doesn't freeze in the winter, try using a lettuce leaf instead.) The other leaf should come from a houseplant; many of these come from very warm climates.
Place each leaf in a plastic bag and freeze it overnight.
Click to download the What Happens When Plants Freeze? handout and fill in your predictions. Then complete it the next day after you take the leaves out of the freezer.

Making Connections

Ask your teacher to share some background information on how different plants cope with freezing temperatures.
If it snows this spring after Journey North tulips are out of the ground, what do you think might happen, and why? Stay tuned to Journey North to find out!
Explain how you think tulips get through cold winters. What "behaviors" and parts help them survive.

Try This!
Write or tell a story of a plant that lives in a cold-winter environment. Help the reader understand what the plant might experience. Does it get through the winter? If so, how?