EXPERIMENT - DOES BREATHING VOLUME CHANGE AFTER EXERCISE? Aim: To discover if breathing volume changes after exercise. Hypothesis: Make an educated guess about how your breathing rate and breath volume will change before and after exercise. Materials: Balloons, string, ruler, stop watch. 1. Breathe out a normal breath into a pre-stretched balloon prior to any activity tying the balloon shut. 2. Wrap the string around the balloon then measure the circumference of the balloon by measuring the string length. 3. Perform at least 2 minutes of moderate exercise. 4. Breathe a breath into a second balloon, tie it off and measure its circumference. 5. Complete steps 1-4 again as a second trial. Complete the following table and create a bar graph of your data. Explain which balloons were bigger and why you think they were. Describe why it is beneficial for breathing volume to increase after exercise. Consider the reaction for aerobic cellular respiration in your answer. Discuss anything you could have done better during this experiment.
EXPERIMENT: DISSECT A SHEEP S HEART [To be performed under teacher direction in a science laboratory] Aim: To observe how the structure of the heart relates to its function. Materials: Sheep heart, scalpel, scissors, tweezers, dissecting board, newspaper, plastic bag, gloves, lab coat. 1. Cover dissecting board with paper, place heart on paper covered board front side up. 2. Explore the openings at the top of the heart and the thickness of both sides. 3. Cut both sides of the heart open revealing the four chambers. 4. Try and find the valves separating the atria from the ventricles. 5. Wrap up the dissected heart in the newspaper and dispose of it. Clean all equipment. Draw a detailed labelled diagram(s) of the heart. Write a detailed description of your observations of the heart. Explain why the left side of the heart is thicker than the right side. Explain why arteries (aorta and pulmonary artery) are thicker than veins (vena cava and pulmonary vein). Discuss anything you could have done better when dissecting the heart. Summarise the way the structure of the heart relates to its function.
EXPERIMENT: SENSE OF TOUCH [To be performed under teacher direction in a science laboratory] Aim: To discover which parts of your skin are most sensitive. Hypothesis: Make an educated guess as to which area of your body is the most sensitive to touch. Materials: Centimetre ruler, toothpicks, rubber bands or sticky tape, blindfold (optional). 1. Attach two toothpicks to a ruler starting about 5cm apart. 2. Working in pairs, have the subject close his/her eyes or wear a blindfold. (The subject may not watch the procedure this would give away the answer!) 3. Gently touch the two toothpicks to the subjects forearm. 4. If the person feels two, move the points closer together about 4cm apart, and check again. Continue the procedure until you find the smallest distance the points can be separated for the person to feel two points instead of one. When the person reports one point for the first time, move the two points apart only one or two millimetres at a time and try to make a very accurate measurement. 5. Record this distance in the results table. 6. Continue this process for the rest of the skin areas (do more if you like) and then repeat for your experiment partner. Complete the table and draw a graph of your data. Write a detailed description of your results and describe which areas of your body are the most and least sensitive and why they are. Which brain area do you think is larger, one receiving information from more sensitive skin, or from less sensitive skin? Explain. Discuss anything you could have done better when performing this experiment.
EXPERIMENT: REACTION TIME Aim: To test your experiment partner s reaction time to see how fast it is. Materials: Metre ruler. 1. Hold the ruler between the outstretched index finger and thumb of the subject s dominant hand, so that the top of the subject s thumb is level with the zero centimetre line on the ruler. 2. The subject tries to catch the ruler as soon as possible after it has been released. 3. Release the ruler and record the distance between the bottom of the ruler and the top of the athlete's thumb where the ruler has been caught. 4. Repeat the test 2 more times and calculate the average drop height. Create a table and draw a graph of your data. Average drop test reaction times for teenagers are: Excellent= <7.5cm, Good= 7.5-15.9cm, Average= 15.9-20.4cm, Low= 20.4-28cm, Poor=>28cm Write a detailed description of your results and assess if your reaction time is fast or slower than average. Explain why it is of a survival advantage to have a fast reaction time. Discuss anything you could have done better when performing this experiment.