You may have been surprised to see the sunflowers in the video bending to face the sun. Plants move much more slowly than people do, so you have to watch over time to see that a plant has reacted to a change. With this simple experiment, you will be able to see for yourself how plants turn to face the light.
Your teacher has set up a plant in the classroom. Look at the plant carefully and notice the direction that its stem (or stems) are growing.
DISCUSS:
Are the stems pointing straight up? Do they lean to one side?
Next, your teacher will put the plant inside of a box, placing it as far from the hole as possible. The plant should be placed so it leans away from the hole, then the box should be closed.
DISCUSS:
What do think will happen? Think about how the sunflowers responded to sunlight.
Your teacher will water the plant regularly. Each time they do, look at the plant’s stem.
DISCUSS:
Are there any changes?
Switch to non-narrated version
|
Knife
|
1 knife |
|
Scotch Tape
Only needed if your box lets light in.
|
Details
1 roll
|
|
Aluminum Foil
Only needed if your box lets light in.
|
Details
10 inches
|
|
Cardboard Box (12x12x11")
|
1 box |
|
Soft-Stemmed Plant
|
1 plant |
As an optional activity, we suggest having students observe and discuss how plants respond to light.
If you like, you can grow your own experimental plant by planting bean, sunflower, or corn seeds a week before you experiment. Buying a bean seedling or an herb such as thyme will also work.
Get your box ready by cutting a hole that’s about two inches square in one top corner. Hold the box up to the light and check for any other places the light might get in. If there are holes other than the one you cut, tape aluminum foil over them since foil is opaque and it won’t let any light through. Make sure your box is large enough so when your plant is a few inches tall, the whole thing will still to fit inside the box.
Locked
6:10
Why is the sky blue?
Locked
4:41
Why do we call them doughnuts?
Locked
5:16
Could a turtle live outside its shell?