Osmosis Lab Walkthrough

Summary

In this educational video, Mr. Andersen guides viewers through an osmosis lab experiment, also known as the potato lab. The process involves using a potato corer to obtain uniform potato cores, which are then placed into six test tubes containing varying concentrations of sucrose solution, ranging from 0.0 molar (distilled water) to 1.0 molar. The potato cores' initial mass is recorded, and after an overnight soak, their mass is measured again to observe changes due to osmosis. The lab emphasizes careful handling to prevent errors and demonstrates the concept of percent mass change.

Takeaways

• 🥔 **Potato Cores**: Use a potato corer to obtain uniform potato cores for the experiment.
• 🔪 **Trimming**: Razor blades are used to trim the potato cores for consistency.
• 🧪 **Test Tubes**: Six labeled test tubes are prepared with varying concentrations of sucrose solution.
• 💧 **Concentrations**: The sucrose concentrations range from 0.0 M (distilled water) to 1.0 M.
• ⏲️ **Timing**: Potato cores are weighed initially and then left to sit overnight before reweighing the next day.
• 📝 **Documentation**: Record the initial masses of the potato cores and track changes over time.
• 🌡️ **Setup**: Transfer sucrose solutions from Erlenmeyer flasks to beakers, then to test tubes for ease of handling.
• 🍽️ **Parafilm**: Use parafilm to seal test tubes and prevent evaporation of the solutions.
• 📏 **Uniformity**: Ensure potato cores are roughly the same size and length for accurate results.
• 📊 **Data Analysis**: Calculate the percent change in mass of the potato cores to understand osmosis effects.
• 🧠 **Understanding Osmosis**: The lab aims to demonstrate osmosis by observing mass changes in potato cores in different sucrose solutions.

Q & A

What is the main purpose of the osmosis lab described in the script?

The main purpose of the osmosis lab, also referred to as the potato lab, is to observe and measure the change in mass of potato cores when exposed to different concentrations of sucrose solution over time.

Why is a potato coring device used in the lab?

A potato coring device is used to obtain a similar amount of potato tissue for each test to ensure consistency and accurate comparison of results across different sucrose concentrations.

How many test tubes are used in the experiment and what are they labeled with?

Six different test tubes are used in the experiment. They are labeled with the experimenter's name and the different concentrations of sucrose, ranging from 0.0 molar (distilled water) to 1.0 molar.

What is the initial step taken with the potato cores before placing them in the test tubes?

The initial step is to trim the potato cores using a razor blade to remove the skin and ensure they are roughly the same size, which is important for accurate mass comparison.

How many potato cores are placed in each test tube and why?

Two potato cores are placed in each test tube to ensure a representative sample size for each sucrose concentration, which helps in reducing variability in the results.

Why is distilled water used in one of the test tubes?

Distilled water is used in one of the test tubes as a control to observe the natural change in mass of the potato cores without the influence of sucrose.

What is the significance of measuring the mass of the potato cores before and after the experiment?

Measuring the mass of the potato cores before and after the experiment allows for the calculation of percent mass change, which indicates whether the cores gained or lost water due to osmosis.

Why is parafilm used in the test tubes during the experiment?

Parafilm is used to seal the test tubes and prevent evaporation of the sucrose solution, ensuring that the potato cores are fully submerged and that the concentration of the solution remains consistent.

How long does the experiment run for?

The experiment runs for 24 hours, during which the potato cores are left to sit in the sucrose solutions to observe any changes in mass due to osmosis.

What is the expected outcome of the experiment in terms of mass change?

The expected outcome is that potato cores in higher molar sucrose solutions will lose mass due to water loss through osmosis, while those in lower molar or distilled water might gain mass as they absorb water.

What is the formula used to calculate the percent mass change of the potato cores?

The formula for calculating the percent mass change is not explicitly mentioned in the script, but it typically involves the initial mass, final mass, and the difference between the two, expressed as a percentage of the initial mass.