Download Dark vs Light - Siemens Science Day

DARK VS. LIGHT
(45-60 Min)
Addresses NGSS
Level of Difficulty: 1
Grade Range: K-2
OVERVIEW
In this activity, students will examine the need for seeds to have sunlight for maximum growth. Students
will discuss key components needed for plant growth and survival. Students will compare plants growing
in sunlight with those growing in darkness.
Topic: Properties of Matter
Real-World Science Topics
• An understanding of the life cycle of a plant
• An evaluation the components required for plant growth and survival
• An examination of plant growth in contrasting settings
Objective
After completing this activity, students should be able to outline the key needs of plants in order to survive.
They will be able to sequence the life cycle of a plant. They will be able to discuss the effects of plant growth
in a dark setting vs. a setting in sunlight.
NGSS Three-Dimensions
Science and Engineering
Practices
Planning and Carrying Out
Investigations
• Plan and conduct an
investigation collaboratively
to produce data to serve
as the basis for evidence
to answer a question.
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Disciplinary
Core Ideas
LS2.A: Interdependent
Relationships in Ecosystems
• Plants depend on water and
light to grow.
Crosscutting
Concepts
Cause and Effect
• Events have causes that
generate observable patterns.
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DARK VS. LIGHT
Background Information
What is the life cycle of a plant?
All plants begin as a seed or bulb. Once a seed receives specific needs, it begins to germinate. This is the
initial stage of growth in which the radicle, or immature plant, begins to grow. Next is the plumule, which
contains the stems and leaves. Once the roots, stems, and leaves are established, the plant will begin to
grow flowers and new seeds. If the plant is fruit-bearing, the fruit typically comes last and then goes through
stages of ripening. Once this occurs, the plant will drop its seeds and begin the life cycle again.
What do plants need in order to grow and survive?
All plants require four elements for successful growth – air, soil (nutrients), sunlight, and water. Soil contains
the nutrients required for plant growth. In addition, it serves other purposes, such as anchoring the plant for
stability. Soil contains oxygen, which is vital for plant growth. Water helps plants grow by helping to maintain
temperatures that promote plant growth. Water distributes nutrients throughout the plant.
What is photosynthesis?
Photosynthesis stems from two words photo meaning light and synthesis meaning together. So, it literally
means using light to put things together. In this case, the light refers to sunlight. Plants take in air much like
animals. They have tiny holes in their “skin” that can only be seen under a microscope. They use those holes
to breathe in a chemical called carbon dioxide. Plants also take in water through their roots. Lastly, tiny cells
found in plants, called chloroplasts, take in water, light, and carbon dioxide and turn them into sugar and
oxygen. This is used as food for the plants and also put into the atmosphere for humans and animals to
breathe. This entire process is called photosynthesis.
Key Vocabulary
Germinate – To sprout an initial plant from a seed
Radicle – The initial plant that begins to grow from the seed
Plumule – The part of the plant containing the stems and leaves
Photosynthesis – The process by which plants take in water, light and carbon dioxide and change them
to sugar and oxygen
Solar – Of the sun
Carbon Dioxide – A colorless and odorless gas that is naturally present in the air and aides in photosynthesis
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DARK VS. LIGHT
Materials Needed for Activity
• Soil
• Chart
• Marker for chart paper
• Sharp object (to puncture holes in paper cups)
• Images from Photobank (Optional)
• Plants (Yellow Flowers on Plant): Naked and Afraid XL
File: 34113-ep101_014.jpg
• Plants (Tropical Hawaiian Plants): Buying Hawaii
File: 32722_ep101_33.jpg
• Plants: Private Life of Plants
PRIVATELIFEPLANTS.002.jpg
• Plants (sunflowers on table): Flowers Uncut
File: 19928_IMG_2692.jpg
For Each Student:
• 1 set of colored or white paper bags
• 1 set of black paper bags
• 2 clear cups
• 2 smaller paper cups
• Soil (unless prepared in advance)
• Seeds that grow easily (lima beans, soybean seeds, sunflower)
• Water
• Shovels
• Trays (optional to use for catching soil)
• Light vs. Dark Monitoring Sheet handout
Discovery Education Video Resource
• Dark vs. Light
Web Resources
Note: Always preview websites before using with students.
http://www.woojr.com/plant-life/
Suggested activities, printables, and a mini book
http://www.turtlediary.com/kindergarten-games/science-games/plant-life-cycle.html
Video showing the parts of a plant and how plants grow
http://www.sesamestreet.org/media/video_1c104d18-4142-11dd-a2c3-4d6bdc929d13?video=1c104d18-414211dd-a2c3-4d6bdc929d13
Sesame Street video about plants not getting what they need
Teacher Preparation
Punch holes in the bottom of all the paper cups so that water can drain once the seeds are water.
Put the soil into separate containers for each table or small group of children for easier access.
Hang chart paper on wall or board and have nearby.
Have all remaining materials ready to use.
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STEPS FOR
DARK VS. LIGHT
1.
Warm-up Activity: Conduct a demonstration showing what might happen if a plant receives too
much water. Display two planter pots. Engage the students in a discussion about the purpose of the
planters. Then, fill each with soil. Lead the students in a discussion about the needs of plants. Be sure to
inquire about all needed elements (sunlight, soil, water, and air). Discuss the idea that if a plant receives
too much or not enough of these, its growth will be affected. Pour a small amount of water in the first
pot. Then, pour an abundance of water in the second pot, allowing the water to overflow. Discuss the
outcome of each scenario.
2.
Use the chart paper to diagram the needs of a plant and photosynthesis. Draw a flowering plant in a
plant pot. Show how the plant takes in sunlight, water, and air (do an online search for images to help,
if necessary). Then, explain that plants take in carbon dioxide and turn it into oxygen. Allow the students
to share any ideas and questions they have related to the diagram.
3.
Explain to students that they are going to plant two seeds. They will use those planted seeds to conduct
an experiment to find out if plants can grow in a dark setting without exposure to sunlight.
4.
Demonstrate to the students how to plant each seed in a paper cup with a hole in the bottom.
• Show them how the hole acts as a filter to drain the water into the larger clear cup.
• Fill the cups 2/3 full with soil.
• Place the seeds into the cups and fill the remaining cup with soil until full.
5.
Show them the two bags and explain that they will place one cup in a white bag and seal it, but leave
it exposed to sunlight (near the window). The other cup will be placed in a sealed black bag and kept
away from sunlight.
6.
Distribute the planting materials. Allow students to plant their seeds in both cups. Then, they should
place the cups in the bags and seal them. Walk around the room and monitor the planting.
7.
Once students are finished, distribute and discuss the monitoring sheet. The students are to open the
bags every two or three days to check for germination and draw what they see.
8.
When the experiment is over, view “What Plants Need to Live” and ask students to discuss anything that
was surprising based on what they learned from their experiment. Ask students to discuss what they
would tell a friend who wants to grow plants from seeds.
Extension Activity
Now that the students have examined the effects of depriving a seed of light, they can conduct the same
experiment again. In the next experiment, they can deprive one of the plants of water and see how long or
if the plant grows at all. They can compare the two experiments to find out what is more crucial to plant
growth: sunlight or water.
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DARK VS. LIGHT
STUDENT HANDOUT
Name: __________________________________________________________________
Date: _______________________________
Light vs. Dark Monitoring Sheet
Now that you have planted your seeds, evaluate them every two or three days. Look at the seedling that is
exposed to the sunlight and draw what you see. Take a peek at the seedling that is kept away from sunlight
and draw what you see. Be sure to close the bags after you look inside!
Plant in the Sun
Plant in the Dark
Day 1
Day 4
Day
Day
Day
Day
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IMAGES FOR
DARK VS. LIGHT
Photo 1
Photo 2
Photo 3
Photo 4
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