Sin título

1. Gather 3-4 spinach leaves and a hole punch

2. Using a one-hole punch, cut 20 leaf disks from the spinach leaves

3. Prepare a sodium bicarbonate and water solution

Weigh 1.5g of sodium bicarbonate in a large beaker

Add 300mL of water to the beaker containing the sodium bicarbonate and stir until fully

dissolved.

Using a pipette, add approximately 2 drops of liquid dish soap to the solution and stir gently

(avoid bubbles!)

Divide this solution evenly into 2 smaller beakers

4. Find the plastic syringe and remove the plunger.

5. Place the 20 leaf disks into the body of the syringe.

6.Reinsert the plunger in the syringe, being careful not to damage the leaf disks.

7. Insert the syringe into the beaker containing the sodium bicarbonate and water

solution. Pull the plunger back to draw up the solution. Draw approximately half the

volume of the syringe can hold (ie draw 15mL if the syringe can hold 30mL). Your

leaf disks should float.

8. Hold the syringe tip upward and expel all the air in the body of the syringe by

depressing the plunger carefully.

10.

Gently release the plunger, then remove your index finger. You should see the

leaf disks sink.

If some leaf disks do not sink, try tapping the side of the syringe.

If some leaf disks still do not sink, repeat steps 8-10 once more.

Do NOT repeat steps 8-10 more than 3 times! It will damage the leaf disks.

If after repeating, some leaf disks remain floating continue to step 11 and

record this in the results section.

14. Observe what happens to the leaf disks. Copy

the chart to the right in your lab notebook under

the “results” section and complete it during the

lab. Stop recording after 15 minutes.

9. Seal the tip of the syringe using the index finger of your left hand and hold the

syringe tightly. Pull back on the plunger creating a partial vacuum (this takes

some force to create the vacuum!) Hold this seal for about 5 seconds.

15. Using the data that you collect, create a double

line graph in your lab report

11.

Remove the plunger from the syringe and pour the leaf disks and solution evenly into the two smaller

beakers.

There should be 10 leaf disks and approximately 150 mL of solution in each beaker

12. Place one beaker approximately 6-10 inches

under a light source (or outside in the sunlight) ,

and place the other beaker in a location that is

covered or blocked from the light.

13. Begin timing the experiment as soon as the

beaker is placed under the light source.