1. Let’s Investigate Great white shark ‘Jaws’ An object that is streamlined will move faster through water than an object that is not streamlined http://www.webweaver.nu/clipart © Sheila Porter – www.scifest.ie

2. Testing a Hypothesis Hypothesis: An object that is streamlined will move faster through water than an object that is not streamlined. Materials: Blu-Tack, tall measuring cylinder & stopwatch 1.Discuss the hypothesis with the other members of your team. 2.Identify the variables (see slides 6 and 7). 3.Draw up an experimental plan. 4.Design a chart on which to record the data you collect. 5.Carry out investigation (Remember you may have to modify your original plan.) 6.Write an account of the investigation into your copybook, explaining your method and describing your results and conclusions. © Sheila Porter – www.scifest.ie

3. Independent Variable Dependent Variable Fixed Variables/ Constants Replicates - Number of times each shape was tested © Sheila Porter – www.scifest.ie Complete the Chart

4. Independent Variable Dependent Variable Fixed Variables/ Constants Replicates - Number of times each shape was tested Shape Time taken to travel distance/speed 1. Mass of object 2. Distance/Height of water 3. Height of drop Three © Sheila Porter – www.scifest.ie

5. Sample Table of Results Shape Trial 1 Time (s) Trial 2 Time (s) Trial 3 Time (s) Average DistancecmSpeedcm/s 1111 2222 3333 © Sheila Porter – www.scifest.ie

6. Discussion What problems did you come across in your experiment ? How did you overcome these problems ? The scientific method is limited in a number of ways, e.g. by the extent of our basic knowledge and changes in the natural world. Can you think of any other factors that might affect the validity of your results. In all practical work safety must be a major concern. Give examples of two safety precautions you observed when carrying out this investigation. © Sheila Porter – www.scifest.ie

7. Animals that move through water © Sheila Porter – www.scifest.ie

8. Extended Discussion 1. Some fish have fusiform (streamlined) bodies, e.g., salmon while others are laterally compressed (flattened from side to side), e.g., sole. The shape of the fish’s body tells us a lot about its lifestyle. Comment on this statement. 2. In what way might the results be useful if you were designing swimwear? © Sheila Porter – www.scifest.ie