Fig 5.1
Lab Report
This is an experimental variation on the celery food dye activity of Lab 5.
Activity
1. Obtain four cups (two of which could have been used in Lab 5). As in Lab 5, fill each cup with 400 ml of tap water. Use red dye to darkly stain two cups, and use blue dye to darkly stain the other two cups. Be sure that each red cup gets the same amount of dye and that each blue cup gets the same amount of dye. Record the drops in each. Add a spoonful of salt into each cup.
2. Label one red dye cup and one blue dye cup with an S (high salt). Add 4 spoonfuls of salt to each of these cups. Stir the solutions thoroughly.
3. Obtain two similar stalks of celery, each with some leaves at the top. Cut a 1-cm piece (about one-half inch) off the bottom of each stalk. Keep the relative lengths of the two stalks as similar as possible.15
4. Carefully, split the stalks up the middle about half-way. The stalks should each now have two “legs.” Be sure that the legs of each stock are similar sized (i.e., the left leg and right leg are the nearly the same length and width).
5. Place the red S cup and the blue S cup together. Gently place one “leg” of one stalk into the red S cup, and the other “leg” of the stock into the blue S cup. The celery should now be “straddling” the two S cups (Figure 5.2.B). Place the red non-S cup and blue non-S cup together and situate the legs of the other celery stalk into each cup (i.e., the celery “straddles” these two non-S cups).
6. Record the time at which you place each celery into the pairs of cups as “Start time.”
| Start time | Stop time | |
| a. S cups (high salt) | ||
| b.Non-S cups (low salt) |
7. Let the celery sit in the cups for 6 hours, or until you can see color in the leaves of one of the stalks. In Step 6 above, record the time when you remove the stalks as “Stop time.”
8. Examine the top of the celery stalks. Are there differences between the celery in the high salt (S) and low salt (non-S) water conditions? Record your observations in Question 1 of Lab Report 6.
9. Remove the celery from the cups (be sure to keep it clear which came from the high salt solution (S) and which came from the low salt (non-S) condition). Lay each stalk out flat. Starting at the top, move down the stalk, making cross-sectional cuts. Stop when you first see evidence of dye. Measure how far up each stalk the red and blue dyes climbed. In Table 6.1 in Lab Report 6, record the distance (cm) traveled by the red dye in high salt conditions (S), the blue dye in high salt conditions (S), the red dye in low salt conditions (non-S) and the blue dye in low salt conditions (non-S).
10. Tear apart the celery stalk. Notice the feel of the vascular tissue, and how the food coloring lies within it.
