Download Sandy seeds notes

Sandy Seeds
(Age 7–9 years)
Teacher’s Notes
Primary upd8 provides relevant contexts and creative hooks for your science lessons.
What’s it all about?
Every year vast areas of Bangladesh are flooded. These floods are likely to get worse due to
climate change. When the flood waters recede the land next to rivers (called the char lands)
is left covered with deposits of sand and silt which do not contain sufficient nutrients to grow
crops. Practical Action is supporting families to grow pumpkins on these lands by digging
pits, adding compost and then planting pumpkin seeds. Some of the pumpkins are eaten by
the family and others are sold at market to provide an income.
In this activity, children will be observing the growth of seeds in sand and compost over time.
Children will be able to work scientifically by:
●
setting up simple observations over time
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recording findings using simple scientific language, drawings, labelled diagrams, keys,
bar charts and tables.
Children will learn:
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about the requirements of plants for life and growth.
Resources needed:
Two pots per group
Sand
Compost
Seeds (e.g. radish – NOT beans or peas)
Spoons/small trowels for transferring sand/compost (peat free)
Watering cans/jugs
Space to leave seeds to grow (indoors or out depending on the
season)
Digital camera (optional) to record changes or software such as
i-motion time lapse to produce a time lapse movie
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Introducing the activity:
Ideas for discussion starters:
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Who had toast/cereal for breakfast?
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What is it made from?
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What would happen to the crops if the land was flooded?
Use the discussion to make connections with the global issue. Even when there is sufficient
sun and rain, there are still places in the world where it is difficult to grow crops.
Show slide 1 to introduce the problem.
The floods in Bangladesh have washed away everything and covered a very large area with
vast banks of sand and silt, causing people to lose their homes, possessions and farmland.
This slide introduces eight-year-old Sujan. Here is the Big question: Is there any way that
Sujan’s family can grow crops in sand?
The Practical Action video (up to 2 mins 45, http://practicalaction.org/turning-compost-intofood and see website links below) shows the scale of the problem and the consequences for
a family. The children can then carry out an investigation into the growth of seeds in pots
containing sand and compost.
The children should be encouraged to consider what variables need to be controlled in order
to be able to make a fair comparison (same amount of watering/light etc) but the focus
should be on making observations over time (see slide 2). The children should plant several
seeds in each pot.
Show slide 3 to encourage children to make and explain a prediction about their experiment.
Ask the children to discuss the statements and to use this to help them to predict what may
happen when one seed is planted in sand and the other in compost. The discussion can be
used to discover any existing misconceptions, for example that plants extract all the food
they need from the soil through their roots.
At the end of the investigation, encourage the children to discuss their observations. How
many seeds in each pot have germinated? Did the seeds in one pot grow better than the
other? Did they investigate how tall the seeds grew or did they look at the number or size of
the leaves?
Discuss with the children why the seed in the sand was able to grow (plants make their own
food through photosynthesis) but why the seed in compost grew better (like them, plants
need nutrients to be healthy). Can the children suggest an answer to the original Big
question: ‘How could Sujan’s family grow crops in the sand?’
Show slide 4: What happened next?
The children could also be shown the rest of the video to find out what happened.
The Practical Action project in Bangladesh has been very successful. Adding compost made
from a mixture of cow dung, soil and water to deep pits in the sand provides the essential
nutrients to allow the young pumpkin plants to grow to maturity. As well as providing food for
the family, these can be sold in the market to raise money. The family can then begin to
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rebuild their lives by buying and growing more pumpkins, and making more money, which
can be used to buy livestock. The additional money can also allow children in the family to
attend school. Farmers can use plant material from the previous year’s crop and the
dung/manure from their livestock to make more compost, making the farming method
sustainable.
You may wish to discuss what gardeners in the UK add to soil to help their plants grow.
Children may think that ‘compost’ has to come in bags from a garden centre. Explain that
people can make their own compost from garden or food waste. Some schools make their
own compost as part of their gardening activities. Manure can help plants in the UK grow too!
Evidence of children’s thinking and learning:
●
the comments the children make when thinking
about their predictions
●
the observations the children make and the
conclusions they draw
●
the comments the children make when discussing
how their conclusions can lead to a solution to the
Big question.
Extension ideas…Cross-curricular links:
The children could grow pumpkins (or other fruit or vegetables) on the school patch or in
raised boxes to eat or to sell to raise money for school (which could be spent enabling more
crops to be grown the next year). They could also make their own compost, which would link
well with the ideas of reducing waste/recycling/health eating.
Maths
This activity can support maths learning in a variety of ways. It gives children the opportunity
for making measurements and carrying out basic calculations, such as using subtraction to
work out how much a plant has grown each week. In addition it can be used to support work
on writing fractions in terms of the number of seeds out of the total number planted that have
germinated.
Science at your fingertips:
Some children may predict that the seed planted in sand will not grow at all. This could
indicate that they hold the misconception that plants take in food through their roots. If
students are surprised that the seed in sand grew, then recap work on plants making their
own food using energy from sunlight to turn carbon dioxide (from the air) and water (drawn
up through the roots) into glucose.
Compost contains additional nutrients that help a plant be healthy and grow more vigorously.
Children may also not understand the difference between germination (development from a
seed to the first sign of leaves) and subsequent growth of the plant. Children may be familiar
with ‘growing’ beans without soil. In fact what that classic experiment does is to show the
conditions necessary for germination (water, oxygen in air, warm temperature and a food
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store in the seed or bean). The seedling then needs to be planted in soil to allow the plant to
grow, flower and produce the beans we eat.
More detail for the teacher…
Plants are made up of cells. Plant cells contain the green substance chlorophyll, which is
critical for photosynthesis. It is these plant cells that need the different nutrients to function
properly. A website link is provided below that shows how the lack of different nutrients
affects crops.
Websites:
For a video showing the problem and the impact of the pumpkin project see
http://practicalaction.org/turning-compost-into-food
For the full technical brief on growing the pumpkins see
www.practicalaction.org/technical-briefs-schools-agriculture
For advice on making compost see http://www.funkidslive.com/features/a-to-z-of-food-healthand-the-environment/c-is-for-compost/
For photos and information on how nutrient deficiency affects crops see
http://www.cropnutrition.com/nutrient-knowledge
Health and Safety:
Please refer to p9–10 in the Association for Science Education publication, ‘Be Safe!’ for
advice about precautions to take with seeds and plants.
Acknowledgments:
This activity was produced by the Association for Science Education in partnership with
Practical Action as part of the Global Learning Programme (GLP).
The GLP is a ground-breaking programme which is building a national network of likeminded schools, committed to equipping their students to succeed in a globalised world. The
GLP helps teachers in Primary, Secondary and Special schools to deliver effective teaching
and learning about international development and global issues at Key Stages 2 and 3.
ASE is providing the science education support for the Global Learning Programme, which is
funded by the UK government. This activity can be found on the Global Learning Programme
www.glp-e.org.uk , ASE Primary upd8 www.primaryupd8.org.uk, and Practical Action
Schools www.practicalaction.org/schools websites.
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Funded by the UK government