Response to stimuli (maintains homeostasis)

Samantha- Stimuli is defined as anything in the environment that causes an organism to react.
For example, light, temperature, odor, sound, gravity, water, or pressure.
Protocol: There are many ways to test whether these unknown substances respond to stimuli. We could pour water on each substance to see how they react to it and observe whether they react in a positive or negative way to the water. We could do this same experiment for many other stimuli also.


Samantha Louis, Collin Burns, and Mia Stern

Response to Stimuli(maintains homeostasis) September 28, 2010

Definition: Anything in the environment that causes an organism to react.

Hypothesis- By adding one drop of distilled water, .9% of saltwater , and 10% of saltwater to each one of the unknown substances and purple onion we will be able to see the response to stimuli.

Materials:
Microscope
Glass Slide
Cover Slip
Purple Onion
Distilled Water
Unknown Substances (A,B,and C)
Saltwater- .9% and 10%
Dropper

Procedure:

1. Set up a microscope.
2. Cut a piece of purple and onion and peel a layer of skin off.
3. Place on glass slide.
4. Place a drop of distilled water on the onion and cover with a slip.
5. Place under microscope and observe.
6. Dab off water and place a drop of .9% of salt water on purple onion.
7. Cover with slip and observe.
8. Dab off water and place a drop of 10% salt water on purple onion.
9. Remove purple onion and clean slide.
10. Add substance A on slide.
11. Place one drop of distilled water and then place cover slip on.
12. Place under microscope and observe.
13. Dab off distilled water and put one drop of .9% saltwater on substance A.
14. Place and observe under microscope.
15. Dab off saltwater and put one drop of 10% saltwater on substance A
16. Place and observe under microscope.
17. Remove substance A and clean slide
18. Repeat steps 10 through 17 with substances B and C

Observations

Purple Onion: Distilled water- Cells are large and somewhat defined.
- Purple pigment is spread out through the cells.






















.9% Saltwater- Cells are more defined but smaller.
- Purple pigment is less spread out.


10% Saltwater- Cells are defined.
- larger in size
- pigment is in one spot, instead of spread out across the cells




Substance A: Distilled water-Substance appears to be gray when it is under the microscope
-Some darker spots than others
-Some more condensed blobs than others


.9% Saltwater- Able to get a clearer visual of cell structure


10% Saltwater- More defined cell structure




Substance B: Distilled water- looks like gray blob



.9% Saltwater- Slowly melted/dissolved when saltwater was added


10% Saltwater- Started out as dark, defined circles. Then slowly dissolved into one massive grey blob


Substance C: Distilled water- tiny and not defined, couldn't make out what it was.


.9% Saltwater- Diamond shape, and are smaller than the .10 diagram. not as defined.



10% Saltwater- Bigger and more defined. Takes the shape of miniature rocks.