Almost all plants need water, air, sunlight, and a place to grow.. Have students discuss what plants need in order to grow.. Explain that they are going to try to help some seeds sprout
Trang 1Plants, Water, and Sunlight
Purpose
To explore the importance of sunshine and water to
a sprouting seed
Process Skills
Predict, Observe, Collect data, Interpret data, Identify
and control variables, Draw conclusions
Background
Plants live almost everywhere in the world, and they need
things to live, just as animals do Almost all plants need
water, air, sunlight, and a place to grow Although plants
can survive with varying amounts of these resources, having
more or less of them will affect how they grow Seeds may
sprout without sunlight, but will not develop into full-grown
plants without it, as they require light to create food via
photosynthesis
Time – Approximately 45 minutes to 1 hour, plus observation
time over ten school days
Grouping – Small groups (groups of 4 recommended)
Preparation tips: Designate a sunny place
where plants can sit for two weeks Punch
a few small holes in the bottom of each cup
Procedure
1 Have students discuss what plants need
in order to grow Make a list on the board
(Make sure they include sunshine and
water.) Explain that they are going to try
to help some seeds sprout by giving seeds
what they need, but students will also
see what happens when seeds do not
get something they need
2 Hand out data sheets Have students put
all their names and the date at the top
3 Pass out four cups to each group Help
students label their cups with a permanent
marker Have them put their names, the
starting date, and each of the following
labels on the cups: “sun—yes, water— yes,” “sun—yes, water—no,” “sun—no, water—yes,” and “sun—no, water—no.”
4 Have students put about 2 cm (1 inch) gravel (or Styrofoam peanuts) in the bottom of each cups, and then put ½ cup soil on top of the gravel This will help with drainage
Materials
(per group)
q data sheet
q 4 small, clean plastic cups (or other small containers)
q seeds (choose fast-growing seeds—try radish or grass)
q ½ cup potting soil for each cup
q gravel (or Styrofoam peanuts)
q 4 disposable foam dishes (or a tray) to catch water drainage
q water
q 1 shoebox or other box
Optional Materials
q ruler
Trang 25 Have students sprinkle a pinch of seeds
in each cup Add a little more soil to just
cover the seeds
6 Have students give the seeds in the “sun—
yes, water—yes” and “sun—no, water—
yes” cups just enough water to moisten
the soil To introduce liquid measurement,
you can have students measure and pour
150 mL (5 ounces) of water into each of
these two cups
7 Place each cup on a drainage plate or the
tray Have students put the “sun—yes,
water—yes” and “sun—yes, water—no”
cups in a sunny place and the other
two cups in the same place, but beneath
a shoebox
8 Ask students to guess what will happen
with each seed Explain that this kind of
guess is called a prediction Have groups
write their prediction for each cup in their
own words, and then have students draw
pictures that illustrate their predictions
If you want students to keep an individual
science log, have them record their own
predictions and sketches, or provide a data
sheet for each student
9 Remind students to give both plants that
receive water the same amount of water
every day, and to keep the right cups in
the sun or the dark Have groups continue
watering and observing the plants for ten
school days Have groups complete the
data sheet with their observations after
five days, and again after ten days
(Optional: Have students measure the
height of their sprouts and record the
measurements on their data sheet.)
10 If possible, allow enough time in this
activity for the seeds to grow leaves You
do not need to introduce photosynthesis
at this point, but it may help students
make an early connection if they see the
plant growing in the sun If some of the
seeds sprout without sunlight, encourage discussion about how this happened and what might happen if the plant stays in the dark And if there are differences in the color of leaves, ask students to explain why they think this occurred
Discussion Questions
Use these questions to guide a discussion about the experiment
1 What else do plants need to grow (besides sunlight and water)?
Refer students to the nonfiction book Plants
to review other things plants need to live, including air, soil (in most cases), food, and
a place to live.
2 Do you think the seeds would have grown without soil? How could we test this?
Answers will vary Students may explain that
a good way to test whether or not the seeds would have grown without soil is to place them
in an empty container or immerse them in water A more productive way to conduct this test is to keep seeds between moist paper towels
or in a dish with a shallow layer of water Many seeds will sprout in these conditions.
3 How many days did it take for the seeds
to sprout?
Answers will vary Discuss when to consider the seed to have sprouted Have students speculate as to why certain seeds took longer
to sprout than others.
4 If certain seeds didn’t sprout, why do you think that happened?
Answers will vary Discuss the wide variety
in nature; each seed naturally sprouts best under certain conditions found in its native area In order to grow these plants on farms and in greenhouses, humans simulate the conditions that will allow the seeds to grow best, particularly in terms of how much water and light the plant will need.
Trang 35 Why was it important to keep everything
the same between the cups, except for
whether or not each cup received sun
or water?
Emphasize the importance of keeping variables
constant for all the seeds, so one can conclude
that the reason certain seeds didn’t sprout
had to do with the seeds themselves, not the
conditions in the experiment.
Conclusion
Use the following question to help students
draw a conclusion
What do seeds need in order to sprout?
Based upon observations in this experiment,
students should conclude that seeds need both
water and light
Extensions and Variations
• Variation: Students can design and execute
similar experiments that explore the effects
of soil versus no soil on seed sprouting and plant growth Have students try to germinate the seeds in plastic zipper bags with moistened paper towels, rather than
in cups
• Field Trip: Take students outside to observe
areas where plants do and do not grow due to availability of light, water, and soil
• Math: Have students compare the growth
among the different groups’ cups and consider why there may have been differences Graph the results
Data Sheet: Students should have drawings of
reasonable predictions and accurate observations.
Trang 4Name Date _ Collect Data
Prediction: The seeds will look like this after
10 days
Observations: The seeds looked like this after 5 days
Observations: The seeds looked like this after 10 days
sun—yes
water—yes
sun—yes
water—no
sun—no
water—yes
sun—no
water—no