1 Put the safety equipment on, such as the glasses and the apron.
2 Take the egg out of the plastic bag carefully use the paper towel to dry it carefully.
3 Place the egg on the balance and record its mass in the data table.
4 Use the measuring cylinder to measure 75ml 10% salt solution. Put them in the beaker. Then use the cylinder to measure 75ml distilled water. Put them in the same beaker.
5 Mix the solution in the beaker. Place the egg in the beaker gently so that it is fully covered and leave it for 10minutes.use a stop watch to help.
6 Take the egg out of the solution carefully use the paper towel to dry it. Then place the egg on the balance and record its mass in the data table. Calculate the change in mass and also enter this in the table. Also record any other observation.
7 Use the measuring cylinder to measure 15ml 10% salt solution.
8 Put them in the beaker. Place the egg in the beaker gently so that it s fully covered and leave it for 10minutes.use a stop watch to help.
9 Take the egg out of the solution carefully use the paper towel to dry it. Then place the egg on the balance and record its mass in the data table. Calculate the change in mass and also enter this in the table. Also record any other observation.
10 Use the measuring cylinder to measure 150ml distilled water.
11 Put them in the beaker. Place the egg in the beaker gently so that it s fully covered and leave it for 10minutes.use a stop watch to help.
12 Take the egg out of the solution carefully use the paper towel to dry it. Then place the egg on the balance and record its mass in the data table. Calculate the change in mass and also enter this in the table. Also record any other observation.
13 Collect the class data and also tabulate this.
14 When finish the practical return the egg as instructed.
Data collection
[Results]
A table showing the relationship between the solute concentration and the egg’s weight changes
Data processing and presentation
.caculation
- (68.944-68.212)/68.212= 1.07%
- (68.633-68.944)/68.944=--0.45%
- (69.725-68.633)/ 68.633=1.59%
.Graph
These two pictures up are showing the relationship between the concentration of the solution and the weight of the egg. In the first graph we can know the water didn’t always go into the egg.
[Conclusion]
The result matches the hypothesis. The rate of osmosis increases the solute of concentration decrease. Although there is one group’s result gets a mistake.
Explanation
As we know the Osmosis is the passive movement of water molecules, across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration. When the concentration of the solution decreases. There is more water in that solution; this means there is more water can come into the egg in the same time. So the rate of osmosis increases.
[Evaluation]
Errors
1 There is still some egg shell on the egg membrane. This will stop the water goes into the egg.
2 The 5% solution we need to make it by ourselves. The concentration might not be the exactly right. It might be lower or higher. This will affect the result. The group7 is evidence. They make it become 7% solution. This make the 5% solution‘s average increase.
3 When you use the balance to weight the egg, there might have the other group’s egg’s solution on. This will influence the weight of the egg.
4 When you use the paper towel to dry the egg the egg won’t be exactly dry. There is still some water there. This will make the weight change.
5 The equipment is not very accurate. This can affect the errors.
6 When you measure the solution, you use a measuring cylinder. So there will always leave some solution on the side. When you get the 5% solution, the concentration might not be right.
7 The room temperature won’t be same, it will always get change. This will make the movement of the water become quicker or slower.
Improvements
1 Try to let the egg to stay in HCl longer to remove all the shell.
2 Use the high quality solution. Prepare the 5% 10% and 0% solution.
3. Clean the balance each time before you weight the egg.
4. Try to use the paper towel to dry longer. This can help to remove most of the solution on the surface.
5 To do more times to get an average, this can help the result mot accurate.
6 Use high quality equipment instead of the measuring cylinder.
7 Try to keep the room temperature always same. Use a air condetional to help.