Procedure. 1  Start with a short lecture on the nature of solid, liquid, and gaseous water. 2  Your goal is to give some understanding that water molecules themselves don't change when the state of the matter changes, but that the interaction between molecules changes.
Check out our guide of what to toss when. Is your important paperwork piling up? Check out our easy-to-use chart to see what to keep, what to toss, and how to store those hard-to-replace documents. Keep tax returns, as well as supporting documents like W-2 forms, receipts, and real estate closing statements for seven years.
What to keep after filing your taxes and how long. Knowing what information to save and for how long can be confusing. As a general rule of thumb, keep tax returns and related documents for at least three years from the April 15 filing deadline. Three years is also the amount of time you have to amend your return. 2  Four years: Many income-taxing states have an additional year to audit individual returns. 3  Six years: Forms W-2, 1099, etc. because the IRS has six years to contact you if you've failed to report income.