Method 1. Placed 500 g of sunflower seeds on the bird table on a cold day. 2. Counted the number of bird visits to the bird table between 10 a.m. and 12 p.m. and recorded the temperature.
3. Placed 500 g of sunflower seeds on the bird table on a warm day. 4. Counted the number of bird visits to the bird table between 10 a.m. and 12 p.m. and recorded the temperature.
Results Temperature
2°C 15°C
Number of bird visits 23
16
Communication of results The student may report his findings to his science teacher and check them with information available from Birdwatch Ireland.
Reviewing and reflecting on the experiment The student used the same mass of sunflower seeds and observed the bird table at the same time of day, which helped to make his experiment fair. However, he only recorded one set of results for each temperature so he does not know if his results are reliable. He also only used one location. To improve his experiment he could repeat it at the same location and also carry out the experiment at different locations.
3. Using a model Models can be used to show or demonstrate situations that are difficult to observe or are very large.
Physical models A physical model is a structure that represents an object, system or process. For example, models of the human heart and brain are often used in schools to show students the different parts. An example of a physical model that shows how parts of a system interact is shown in Fig. 10 on the next page. This model of the human breathing system can be used to test the hypothesis that movement of the diaphragm causes inhalation and exhalation.
