Starch Test Experiment

Experiment 1: Testing for starch in food (bread, potato etc) and in a leaf.

 

Results:

Materials Tested Colour change Labelled diagram (or photographs)
Bread  dark blue  

Potato dark blue
Leaf only the green part of the leaf turns dark blue.

 

EXPERIMENT 2: Is light needed for photosynthesis?

RESULT:

 

In the experiment above, the middle part of the leaf is covered by a piece of aluminium foil while the stalk is still attached to the plant.  The plant is left under the sunlight to allow the photosynthesis process to continue to take place and glucose is made in the uncovered part of the leaf. This glucose is converted into starch and stored in the leaf.  (Glucose is a simple molecule and these molecules combined to make large complex molecules called starch).

What is happening to the covered part of the plant?

Glass is transparent and allows light energy to travel through it. However,  aluminium is opaque and does not allow light to travel through it. This part of leaf covered by aluminium will not receive the needed sunlight and the leaf will not be able to carry the photosynthesis process.  This means the covered part of the leaf will not be able to make starch while the uncovered part of the leaf continues to make starch.

What is photosynthesis?

 Photosynthesis refers to the process where plant takes in the carbon dioxide produced by all breathing organisms and reintroduces oxygen into the atmosphere. Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight and turn it into chemical energy.

Chemical equation of photosynthesis:

Discussion:

  1. Why part of the leaf is covered with a piece of aluminium foil?
  2.  Why was the plant left in the sun?
  3. What happens when the leaf is tested for the presence of starch?
  4.  Explain why a part of the leaf covered by the foil will not show the presence of starch?
  5. How does this experiment support the idea that sunlight is needed for photosynthesis?

 

 

 

Hibiscus Flower Dissection

 Hibiscus Flower dissection

  (1) Photograph of labelled parts of a Hibiscus Flower:

Table:
Parts of the flower. Number Colour
sepals     5    green
petals     5   pink
Stamens   many (hundreds)   light pink
Style    5    light pink
Stigma     5    dark pink

 Hand-drawn labelled parts of a Hibiscus Flower:

 

 

(2) Hibiscus Flower (Lengthwise -more detailed diagram)

...

Parts of a Hibiscus Flower:

SEPALS (found at the end of Calyx)

The pointed ends called sepals ae found at the bottom of the flower. The green sepals protects the bud of the flower.

Petals

  • Every flower has multiple petals, which differ in colour depending on the species.
  • The colourful petals attracts animals and insects. This attraction helps ensure the pollination of the flower.
  • The bees and the animals (birds) are called the pollinators and they help to transfer the pollens to the stigma and this process is called pollination.

Female Reproductive organs (pistil)

  • The pistil is the female part of the flower; its function is to produce seeds.
  • The pistil consists of the ovary, stigma and style.  The pistil is a long tubular organ.
  • The stigma is where pollen is collected and it at the top of the pistil. In the middle is the style. This is the section that the pollen travels down to the ovary.
  • The ovary lies at the bottom of the blossom. In some flowers there are several ovaries, but the hibiscus has just one.
  • After fertilisation (pollen travels down to meet the ovules (eggs), the ovary develops to become the fruit and the ovule develops to a seed.

 

Male Reproductive organs (stamen)

  • The male part of the flower is the stamen and is responsible for producing pollen.
  • Anthers are two tube-shaped objects that release the pollen. The anther is usually, but not always, yellow.
  • Anthers sit on a long thin tube called a filament. Together, these organs make up the male part of the flower known as the stamen (anther + filament = stamen). Some flowers have a few stamens, but the hibiscus flowers have hundreds.

 

 

iSTEM Stage 5 Aeronautics – Gliders -Resources

iSTEM        STAGE 5 Aeronautics  – Gliders

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