Osmosis Lab Or Fresh Water vs. Sea Water
Procedure Write down Procedure (Notebook pg. 32) • Make Table #1 (Notebook pg. 32) • Fill out table #1 with class • Make table #2 (Notebook pg. 33)
procedure • Make Hypothesis for each cup (What will happen to the length of the potato?) • Measure potato slices carefully (Put in table #2) • Make sea water solutions (LABEL) • Drop potato slices into sea water solutions and cover with plastic wrap
procedure • MAKE SURE TO GET THE CORRECT POTATO INTO THE CORRECT SOLUTION
Fresh Water vs. Sea Water A shipwrecked sailor is stranded on a small desert island with no fresh water to drink.
Fresh water vs. sea water She knows she could last without food for up to a month, but if she didn’t have water to drink she would be dead within a week.
Fresh Water vs. Sea water Hoping to postpone the inevitable, her thirst drove her to drink the salty seawater.
Fresh water vs. sea water She was dead in two days.
Fresh water vs. sea water Why do you think drinking seawater killed the sailor faster than not drinking any water at all?
Fresh water vs. sea water Today we explore the cause of the sailor’s death. We’ll prepare solutions of salt water to represent the sea, and we’ll cut up slices of potato to represent the sailor.
Fresh water vs. sea water Potatoes are made of cells, as is the sailor!
objective To determine the cause of the sailor’s death, we will determine the effects of salt water on slices of potato. Our assumption is that potato cells will behave like the sailor’s cells in her body. We will compare salt water to fresh water so we can see if there is any effect caused by the salt in the water. The fresh water acts as a control in this experiment.
hypothesis • I think that the 10% salt water solution will cause the potato slice to… • I think that the 5% salt water solution will cause the potato slice to… • I think that the 1% salt water solution will cause the potato slice to… • I think that the fresh water solution will cause the potato slice to…
Osmosis lab day 2 (Put this information on pg. 35 in your notebook) • Collect cups • Remove potato slices carefully • Measure slices accurately • Fill in Data Table #2
Osmosis lab day 2 • Throw potato slices and plastic wrap in garbage • Dump out cups and stack on lab table • Answer questions on last page of lab handout (notebook pg. 34) • Make Bar Graph of results from Data Table #2 for Day 1 and Day 2 potato lengths – put in notebook pg. 34 or 35
Formal lab report • Rough draft – Written in notebook • Final draft – Written in the following format
Final draft PROBLEM: • The problem we are trying to solve is… • This problem is important because… • The information that is important to know before we begin is… • The control in this experiment is… • This is the control in the experiment because…
Final draft PROBLEM: • My hypothesis was… • I made the hypothesis that the 10% salt solution water would cause the potato slice to… • I made the hypothesis that the 5% salt solution water would cause the potato slice to… • I made the hypothesis that the 1% salt solution water would cause the potato slice to… • I made the hypothesis that the fresh water would cause the potato slice to…
Procedure • Materials List – List all materials used in the experiment. • List in order how the experiment was performed. • The first thing I had to do was ____________ • The next thing I had to do was ____________ • After that I ________________ • Finally I _______________
results • What quantitative and qualitative observations were you able to make? (list) • Quantitative observations are number type observations. • Qualitative observations are opinions or color observations. • Data table (taken from your notebook) • Graph
OBSERVATIONS AND CONCLUSIONS • When the potato slices sat in the water overnight they _______________ • I think the potato slices did this because ____________ • Is diffusion, osmosis, or active transport responsible for the changes in the slices? • Define: • Diffusion • Osmosis • Active transport
OBSERVATIONS AND CONCLUSIONS • The ______ solution is isotonic to potato cells. A. I know that the solution _______ is isotonic to the potato cells because _____________ • Define: • Hypertonic • Hypotonic • Isotonic
OBSERVATIONS AND CONCLUSIONS • The sailor died more quickly drinking salt water than not drinking any water at all because _______________. • I think the sailor died from ____________ • My hypothesis was correct. OR My hypothesis was not correct. A. My hypothesis was correct because __________. OR My hypothesis was not correct because ____________.