Seeing

Our ability to see upon our eyes ability to bend light and focus the light onto the retina. The light is bent by the cornea and the lens. Once the image comes into focus on the retina, the optic nerve transient an electrical message to the brain so that we can process the information. The iris changes size to alter the amount of light that enters the eye.If the image fails to be focused on the retina, the image will appear blurred.



Short sighted vision

Myopia is the medical term for nearsightedness. People with myopia see objects more clearly when they are close to the eye, while distant objects appear blurred or fuzzy. Reading and close-up work may be clear, but distance vision is blurry.

Long sighted Vision

Also known as hyperopia is an abnormal condition of the eye in which vision is better for distant 

objects than for near objects. It results from the eyeball being too short from front to back, causing images to be focused behind the retina. 

The eye

Noble gases

1. Name the noble gases and list their symbols
Helium- He, Neon- Ne, Argon- Ar, Krypton- Kr, Xeon- Xe, Radon- Rn

2. Explain why noble gases are so un reactive
Noble gases are so un-reactive because they have a full outer shell, so they are stable without having to react to gain or lose electrons.

3. Even though noble gases are usually un reactive some do form compounds under certain extreme conditions. Examine what compounds the noble gases form.
Usually heavier noble gases can form compounds, especially with fluorine and oxygen.
The compound that argon forms is- HArF
Krypton can form KrF2 when in reacts with fluorine
Radon can form RnF2.

Swimming pools

Q1 describe how ph levels of pools are tested

Using your swimming pool test kit you will use the large tube and fill it up to the top solid line with pool water from a depth of 18 inches. Add one drop of solution No. 4 and mix by gently swirling. This solution is sodium thiosulfate, a chlorine neutralizer. 

Add five drops of Solution 2, a phenol red indicator, and mix by gently swirling. Then you have to compare the color with the pH color standards on the plastic tester.

Q2 how to keep your pool at Ph level 7.2 

To raise or lower pH, a pool custodian simply adds acids or alkalis into the water. For example, adding sodium carbonate (soda ash) or baking soda will generally raise the pH, and adding muriatic acid or sodium bisulfate will lower the pH.

Household substance experiment

Aim:
To see what Ph are the house hold items.


Method:
1.Place a drop of lemonade into the tray
2.Add one drop of universal indicator
3.Record the colour change
4.Repeat for all house hold substances.


Safety precaution:
Wear safety glasses



Results:







Household items
Lemonade
Lemon juice
Bi-carb soda
Cloudy ammonia
Apple juice
Vinegar
Radiant
Washing detergent

Acids and Bases

Indicators experiment

  

1. Draw a 4 by grid onto a piece of paper
2. Label the first column indicator.
3. Label the second column acid.
4. Label the third column neutral
5. Label the column base.
6. In the first column record the names of the indicators, litmus, universal indicator, phenolphthalein, methyl orange, bromothymol.
7. Place a plastic sheet over the top of your grid.
8. In the acid colomn
9. Repeat for the natural (water) and base (NaOH)
10. Add a drop of indicator to each of the rows as listed.

Results



Discussion
1. Which indicator is the most useful.
The Universal indicator

2. Which indicator is the least useful
Phenolphthalein

CONCLUSION
The indicator changes the colours of the different