Teacher's Pages
Activity 19 - More Opportunities to Apply the Ideas
Activity 19 - Students Pages
Purpose:
These activities present problems that students can
solve (at least partially) by using the
concept of photosynthesis. Their successes and struggles with
these problems will serve as an important assessment tool for the teacher.
Options and Recommendations:
Use any or all of these problems. In
addition, there are many other ways you could extend students' opportunities to try using the new
ideas and to work on changing their incoming misconceptions to more scientifically
appropriate ways of
thinking. For example, you could examine particular kinds of plants and how they are particularly adapted
to do photosynthesis (cacti, insect "eating" plants, etc.)
Comparing Food for Humans and Food for Plants
Desired Student Response:
How many sources of food do they have?
What is their food?
Where do they get their food?
How do they get their food?
When can they get/make their food?
HUMANS
Many meat, vegetables, etc. farms, gardens, stores grow it or buy it at the store
anytime
PLANTS
one-what they make in photosynthesis
sugar which is made during photosynthesis
it is made in their leaves
make it in their leaves
in the sunlight only
CAVE PROBLEM DESIRED RESPONSE:
The seeds will start to grow but then die. They can begin to grow
using food stored in their cotyledon. That food came from photosynthesis in the parent plant -- extra food
was stored in the seed. The embryo will use that stored food to begin to grow. When that food runs out,
the embryo has to use carbon dioxide, water, and sunlight to make its own food (photosynthesis). But
the small plants in the cave will not get light so they cannot make their food. So they will starve to death.
WINTER PROBLEM DESIRED RESPONSE:
Because the pine needles are thick and have very little surface
area compared to other leaves, they can save water and keep their insides warmer. Thus, the water will
not freeze inside the needles. Since the tree has water and air and sunlight, it can still make its own
food. Although the cold weather will slow down the process greatly.
NIGHT PROBLEM DESIRED RESPONSE:
Plants can use food that was made and stored during the day.