1. First, place 3 bottles of the same size and shape on a table 2. Measure the height of the first bottle. Using the permanent marker and ruler, make a small mark at exactly halfway up the bottle. Fill this bottle with water up to the mark you made 3. On the second bottle make a small mark at exactly three quarters up. Fill this bottle with water up to the mark you just made 4. Leave the third bottle empty 5. Blow across the top of the empty bottle, as you did before. Make sure you can make a clear note. Then blow across the top of the half-full bottle. Note the changes of pitch (highness or softness of sound) between the two bottles you blew from 6. Then blow across the top of the bottle that is three-quarters full. It may take some practice to make a note from this bottle. 7. Overall, how do the notes made from the three bottles compare with one another? Why do you think that is?​