Combining the two clear colorless liquids is a chemical change because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically. Insoluble means that the solid will not dissolve. Give Each Student an Activity Sheet.
There are various regulations which may vary depending on where you live and the dropzone you have chosen. In most cases you will need to be 18 years old to start skydiving. If you are 16-18 years old, your parents may give the agreement for you. But again, it depends on the dropzone and country. Some countries may have no regulations, but I would advice you to stay away from the drop zones in them.
In essence, you must have had a stable prescription for at least two years, and then only you should plan to undergo LASIK surgery. If you wish to go for custom LASIK, the minimum age is the same as that for conventional LASIK. There is no upper age limit for LASIK surgery.Even a 50 or 60 year old person may opt for LASIK. The point is that LASIK can very well correct the refractive error of a myopic patient at any stage of the patient's life, provided the patient's eyes are otherwise healthy. preoperative examination conducted prior to the age of 18 might result in incorrect measurements, and consequently, an appropriate correction via LASIK. Patients suffering from a higher degree of myopia or astigmatism should defer the surgery a wee bit longer than others-normally until the age of 21 or so.