GOOGLE Slides: Total Dissolved Solids (TDS) Lab; What are they? - PDF document

NAME:_________________________________________ Class:_____________ Date:________________ GOOGLE Slides: ​ Total Dissolved Solids (TDS) ​ Lab; What are they? For this lab, we will test various water samples to find out how much Total Dissolved Solids (TDS) are present using a TDS Meter. The unit for TDS is ​ ppm ​ , which is “ ​ parts per million ​ ” and this unit gives us an idea of how many dissolved particles are in a given sample. It does not tell us what the particles are ​ specifically. Some of the particles that could be present are: salt (NaCl), chloride, calcium, magnesium, potassium, sodium, and some small amounts of organic matter. Pre-Lab Questions: A) ​ Why does water have dissolved solids in it? (slide 4) ● Water is a good ______________________ and picks up solids easily. ● A solvent “dissolves” other materials, _______________________ them apart. ● Pure water -- tasteless, colorless, and odorless -- is often called the universal solvent. B) ​ What is the ​ range of acceptable levels of TDS for “average tap water” ​ ? (see chart) B) ​ What does ​ WHO ​ stand for? C) ​ What are types of Dissolved Solids (particles) may be found in drinking water (6)? D) ​ Where do TDS in fresh water come from? (slides #7 to the end) 1. 2. 3.

NAME:_________________________________________ Class:_____________ Date:________________ 4. 5. 6. E) LAB RAW Data: ​ (see the board, copy down) Description of Sample: Prediction: Actual reading (Water source, ex. tap, fountain, well water, High TDS ( > 500 ppm) from TDS meter: pond, river, stream, bottled water etc) Med TDS ( 300 - 499 ppm) Low TDS ( 0 - 249 ppm) Mystery water school ? high 570 ppm F) Answer these questions, ​ in sentences ​ , ​ ON LOOSELEAF ​ , and attach to this page to pass in. 1) Explain what the experiment revealed about drinking water. 2) What could have contaminated or affected the readings of the TDS meter? 3) Web Research: What is a Water Purifier? What is a Water Softener? 4) Web Research: Sometimes a town or city will order a “Water Boil Order” after a big rain and a large amount of run-off has got into the municipal water system. This means in order to use the water coming into your home for drinking, cooking or even brushing teeth, you must boil it for 1 minute. Why?

NAME:_________________________________________ Class:_____________ Date:________________