EXERCISES SHOWING PROCESSES IN PLANT GROWTH 119 



transfer them, putting those that were in the solution in the distilled 

 water, and those that were in the water in the solution. Examine 

 after a few hours and explain. 



3. Movement of Plant Fluids. Cut * a stem of a Begonia two 

 or three inches from the surface of the soil, and place the severed part 

 in a glass of water that has been colored with some analine dye or red 

 ink. After twenty-four hours, remove and cut the stem at various points 

 and examine. Fasten a small glass tube on the stump by means of 

 adhesive tape, and keep the roots well watered. Note the rise of water 

 in the tube. Explain. 



4. Transpiration. Take a small actively growing plant and tie a 

 piece of sheet rubber over the pot allowing the plant to project through a 

 small opening; invert a glass over the plant and note the moisture which 

 collects within the next few hours. Where did it come from? Cut a 

 bunch of fresh growing plants or a cabbage and weigh. Allow to wilt 

 and dry and then weigh again. Dry in an oven, but do not char, and 

 weigh again. Explain. 



5. Plant Food. Secure a quantity of coarse, clean sand, and fill two 

 flower pots or cans of equal size with equal quantities. Plant several grains 

 of corn of approximately the same size and character in each. Water 

 one from time to time with rain water or distilled water and the other 

 with soil solution. Soil solutions may be prepared by filling a larga pail 

 two-thirds full of rich soil or well rotted manure and then adding enough 

 water to make a thin slop. Stir, allow to settle and draw off the water. 

 Refill with water and allow to stand until needed again. In which pot 

 do the plants grow best? Why? 



6. Moisture in Wood. Weigh a piece of green wood. Heat -until 

 thoroughly dry. Weigh again. What has it lost and how much? 



7. Carbon in Wood. Burn the wood until charcoal is formed. This 

 is almost pure carbon. Weigh again. What has been lost and how much? 



8. Ash in Wood. Burn the charcoal. What have you remaining 

 and how much? 



9. Carbon in Sugar. Put a little white sugar in a test tube and 

 heat. What happens? Explain. 



10. Study of Oxygen. Mix a teaspoonful of potassium chlorate 

 with about one-fourth the amount of finely powdered manganese dioxide. 

 Put the mixture in a large test tube or small flask. Close the container 

 with a stopper through which a small delivery tube passes. Fix the con- 

 tainer in a slanting position on an iron stand, and run the free end of 

 the delivery tube into a tray of water. Heat the mixture gently with gas 

 or alcohol flame. Fill several bottles with water; invert one over the 

 mouth of the delivery tube in such a manner that the water will be 



* The stem should be held in the liquid during the cutting so that 

 the cut surface is not exposed to the air. 



