Experiment 6

We now know that for seeds to germinate and plants to grow and develop – water oxygen and a suitable temperature are vital. Water has been dealt with in experiment 5 – now lets find out what factors influence the temperature of soils.

1. Comparing heat absorption in wet soils and dry soils.

Resources:
Two test tubes, hot water , 2 soil samples ( same type): one wet, the other dry, beaker, 2 thermometers

Procedure
Set up equipment as shown below:

Record temperatures of each, every 2 mins. Until pattern develops.
  • Why place the thermometers so high up in the test tubes ?
  • Why not have hot water coming up higher in the beaker ?


    • 2. Comparing heat absorption in bright and dark soil.

    Resources:
    Two small boxes 30 cms X 30 cms X 15 cms deep, each box filled with soil and marked ‘’A’’ and ‘’B, light bulb, 2 thermometers, ‘’chalk’’ and ‘’coal dust’’.

    Procedure:
    Set up apparatus as follows. Fill each box with soil and mark boxes ‘’A’’ and ‘’B’’. Cover soil ‘’A’’ with coal dust and Soil ‘’B’’ with chalk dust. Place a thermometer 5cms deep into each soil and place a light bulb above the soils, equidistant from both. Record temperature rise @ 2 min intervals until pattern develops. Record your results.

    3. Comparing the effects of aspect or slope on heat absorption.

    Resources:
    Two small boxes 30 cms X 30 cms X 15 cms deep, each box filled with soil and marked ‘’A’’ and ‘’B, light bulb, 2 thermometers.

    Procedure
    Using the boxes from experiment above (2) and do the following.
    Have a light shining directly over soil box ‘’A’’ and at right angles to soil box ‘’B’’. Same soil type in each box. Thermometers 5cm deep in both. Again record temps. @ 2 min. intervals until a pattern develops. Is it true that fields with a southern aspect are warmer, therefore better than fields facing North, East or West ?
    Record all your results carefully in your notebooks.