2016年12月8日 星期四

F2 IS EXP 06 Answers

1st Term EXP 06
Submission date_____________
Name______________________
Class & no.2 _________(     )
 
Experiment 7.5A: Gaseous exchange (氣體交換) of
grasshopper (草蜢) mealworms (麥皮蟲) (P.48-50)


Objective: To study the gaseous exchange of mealworms in bright and dark conditions.

Procedures:
1.      Place the following set-ups in a bright place.
2.      Measure the distance (距離) between the stopper and the red ink marker in
    each capillary tube (毛細管). Take measurements (量度) again after 5 minutes.

Results:
Set-up
Distance between the stopper and the red ink marker (cm)
Just after setting up
After 5 minutes
A
10.2
1.1
B
11
11.1

Discussion:
(a)    Explain the results in set-up A.
The mealworms take in oxygen from the air in the boiling tube and releases
carbon dioxide.
Soda lime absorbs (吸收) carbon dioxide from the air in the boiling tube.
The total amount of the gas inside the boiling tube decreases (increases / decreases).
As a result, the red ink marker moves towards (towards / away from) the boiling tube.

(b)   What is the use of set-up B?
There is no mealworm in set-up B. If there is any change in the position of its red ink marker,
it means there are changes in other factors, e.g. temperature and air pressure. These factors
will also (not / also) affect set-up A.
By comparing the results in set-ups A and B, we can know the actual effect (真正影響) brought
about by the mealworms in set-up A.
Set-up B is known as the control experiment for set-up A.




(c) Study the design of set-up C as shown below.
What condition does set-up C simulate (模擬), compared with set-up A?
Set-up C simulates the condition at night (in the daytime / at night) while
set-up A simulates the condition in the daytime.

Design a control experiment (對照實驗) for set-up C. Draw a labelled diagram to show it and call it set-up D below.








The following table shows the results of set-up A and B.
Set-up
Distance between the stopper and the red ink marker (cm)
Just after setting up
After 5 minutes
A
9
2
C
8
1

(c)    Explain the results in set-up C.
The mealworms takes in oxygen from the air in the boiling tube and releases
carbon dioxide which is absorbed by soda lime.
The total amount of the gas inside the boiling tube decreases.
As a result, the red ink marker moves towards the boiling tube.

(d)   What is the use of set-up D?
There is no mealworm in set-up D. If there is any change in the position of its red ink marker, it means there are changes in other factors, e.g. temperature and air pressure. These factors
will also affect set-up C.
By comparing the results in set-ups C and D, we can know the actual effect brought about by the
mealworms in set-up C. Set-up D is known as the control experiment for set-up C.

Conclusion:
Ø   The mealworm takes in oxygen and releases carbon dioxide in both bright and dark conditions.

Ø   The gaseous exchange of the mealworm is the same in both bright and dark conditions.

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