The document describes tests Nicolai 7C performed on a doughnut to identify its components. Small pieces of doughnut were tested for fat, starch, protein, and glucose. The fat test showed the doughnut was transparent under light, indicating it contained fat. Tests for starch, protein and glucose involved adding reagents that resulted in color changes, confirming the presence of each component. The document also outlines the six main parts of the digestive system and how a doughnut would be broken down at each stage.

1. Doughnut
By Nicolai 7C

2. • This is a picture that shows the nutrition
facts of a doughnut.

3. Testing for Fat
• For the fat test, I cut off a small piece of the
doughnut and rubbed it onto a filter paper
for about a minute. After finishing that, I
held up the filter paper in front of a light
and realized it was transparent. That
showed that the doughnut had fat in it.

4. Testing for Starch
• When testing for starch, I
cut off a small piece of the
doughnut and put that piece
into a spotting tile and
added 2 drops of iodine
solution to the doughnut.
The doughnut then turned
black, which showed that it
had starch in it.

5. Testing for Protein
• When testing a doughnut for protein, I cut off a
small piece of the doughnut, added about 2
drops of water onto it, and then crush it so that
it becomes nearly powder. When this is done, I
put the crushed doughnut piece into a test tube
that is half full of protein solution, and I added
10 drops of biuret solution to the test tube.
Then mix it together. From blue, the liquid
inside the test tube turned purple, which meant
the test was positive

6. Testing for Glucose
• When I tested for glucose, I cut off a little piece off
the doughnut and then added 2 drops of water
onto it and then crushed it into nearly powder.
Afterwards, I put the crushed doughnut piece into
a test tube which was filled with 1 5th of glucose
solution. Later, I added 10 drops of benedict’s
solution to the test tube. I mixed carefully and then
put the test tube into a water bath and waited for
around 5 minutes before I took it back. I realized
that the liquid inside the test tube had turned from
blue to orange.

7. Mouth
• The digestive system starts with the
mouth. The teeth chop and grind op the
doughnut. Then Saliva is produced and saliva
contains enzymes that break down any
starch in the doughnut.

8. Stomach
• The second part of the digestion system is
the stomach. The stomach is a muscular bag
that mixes digestive juices with the food.
Enzymes in the digestive juices starts
breaking down any protein in the doughnut.

9. Duodenum
• The third part of the digestive system is the
duodenum. Enzymes in the duodenum
complete breaking down all the starch and
protein into sugar particles. Then bile
comes and rips the fat particles into tiny
bits, and then enzymes break down the fat
even more.

10. Ileum
• The fourth part of the digestive system is
the ileum. In the ileum, sugars, fats, and
proteins are now small enough to be
absorbed. They are absorbed into the blood
stream by small finger-like extensions called
villi. What is now left of the doughnut is
undigested waste, mostly made up of
roughage and water.

11. Colon
• The fifth part of the digestive system is the
colon. As the doughnut travels to the
rectum, most of the water is absorbed.

12. Anus
• The sixth and last part of the digestive
system is the anus. What is left of the
doughnut is a small amount of an
indigestible solid waste which is stored in
the rectum. The doughnut is then expelled
through the anus.