4. Now pour 3 L of room-temperature water into the prism. Shine the laser and mark the new position on the wall. Measure and record the temperature. Label this Trial 1. **Note: Remember to label your points as you mark them.**
5. Add 60 g of salt to the water and mix the water until the salt is mostly dissolved. Shine the laser and mark the new point again. Measure and record the temperature, and record the amount of salt added. Label this Trial 2.
Repeat Step 5 four more times.
e rst time, add another 60 g of salt.
e second time, add 60 g of salt.
e third time, add 180 g of salt.
e fourth time, add 90 g of salt.
(You will now have a total of six trials)
7. Siphon out the water using the rubber tube. (While one end of the hose sits in the water, suck the other end of the hose until the water begins to ow, remove the hose from your mouth, and let the water continue to ow out until the prism is empty.)
8. Rell the prism with 3 more liters of room-temperature water and repeat Step 4. (Label this either Trial 1 of a new table, or Trial 7 of the same one.)
9. Repeat Steps 7 and 8 two more times: rst with hot water, then with cold water.
10. Siphon the water out and shine the laser through the plastic one more time. It should be in the same spot as it was in Step 3.
is is to certify that the point has not drastically moved. If it
has, then your setup was bumped during the experiment and you will end up with a large error.