How will varying the surface area of the bob affect the period of a pendulum? Independent and Dependant Variables: The surface area of the bob was varied by melting chocolate into different shaped blocks with the same volume. The resulting effect on the period of the pendulum was measured. The independent variable in the experiment was the surface area of the chocolate blocks and the dependant variable was the period of the pendulum.Controlled Variables: The purpose of this experiment was to determine the effect of surface area on the period of a pendulum. This was does by varying the surface area of several blocks of chocolate and then measuring the period of the pendulum.
Several variables however, can alter the results of this experiment. Controlled variables: Pivot point- The type of pivot point could affect how the pendulum swings by increasing the friction and changing the velocity of the pendulum. In this experiment the type of pivot point was kept constant throughout the experimentLength of the string- The length of the string will vary the arc on the pendulum and the period as a result will change.
Using a ruler for increased accuracy the string length was kept as consistent as possible. Air Resistance- The amount of air resistance could have been altered by movement, talking, and other changes such as opening and closing the door. These instances could change the flow of air, which could affect the path of motion by the pendulum and change the period.
This was kept to a minimum as the room was closed for the most part during the experiment and had no windows, and motion was kept to a minimum.Type of string- The type of string could affect how the pendulum swung due to its weight and thickness, the type of string was kept constant during our experiment. Mass- The mass can affect the velocity of the bob, using an electronic scale the mass of the chocolate was kept as close as possible. Room temperature- The room temperature can affect the density of air increasing or decreasing the resistance encountered by the bob, this variable was monitored as no significant variation was evident during the duration of the experiment. Time measurement device- To increase the accuracy and diminish the significance of human error in counting, a stopwatch was used to keep track of the duration of the pendulum’s period.Angle-The angle at which the bob was dropped can influence the velocity imparted from the force of gravity.
The bob in each trial was dropped from a 40 angle, and due to the string length being constant, the amplitude from which the bob was dropped was constant. Force- The force imparted on the pendulum will change the velocity and thus the period of the pendulum. In this experiment no force was imparted on the bob during the trials, the only force present was gravity which was constant throughout the experiment. Stability- The stability of the retort stand could alter the path of the pendulum, the shaking of the retort stand was kept to a minimum as it was held by a group member to keep it stable.
1. Four wooden slats were acquired. 2. On the first wooden slat 2 cm, 4 cm, 6 cm and 8 cm from the left edge were marked, and 1 cm and 2 cm from the bottom were marked. 3. On the second slat 1.
5 cm, 2 cm and 3 cm from the right edge were marked, and 1 cm and 2 cm from the bottom were marked. 4. Steps 2 and 3 were repeated on the remaining two wooden slats. 5. The slats were arranged to obtain the dimensions: 1cm x 2 cm x 6cm 6.
Chocolate chips were obtained.7. Using a microwave, the chocolate was melted in a microwave safe plastic container at 20-second intervals, stirring occasionally until the chocolate became liquid. 8. Using a small spoon the chocolate was poured into the mould created by the wooden slab.
9. The chocolate was allowed to cool in the refrigerator until it had solidified. 10. Using a straight edge knife any excess chocolate was shaved off so the appropriate dimensions are obtained. 11. Steps 5 to 10 were repeated four additional times, with the wooden slabs having the following dimensions instead: 1cm x 3cm x 4cm, 2cm x 2cm x 3cm, 1.5cm x 2cm x 4cm, and 1cm x 1.
5cm x 8cm.12. Using an electronic scale, the masses for the chocolate blocks were obtained to ensure the uniformity of mass between each block of chocolate (since the volume of each block of chocolate was the same, the resulting mass should be constant as well). 13.
String was tied around each block of chocolate making sure that the side facing up (where the knot leading to the pivot is located) is: 2cm x 6cm for the 1cm x 2cm x 6cm block, 2cm x 3cm for the 2cm x 2cm x 3cm block, 1cm x 4cm for the 1cm x 3cm x 4cm block, 1.5cm x 4cm for the 1.5cm x 2cm x 4cm block, and 1cm x 8cm for the 1cm x 1.
5cm x 8cm block. 14. String measured to 60 cm in length from the centre of the side of the chocolate facing up, was cut using scissors, this was done for all pieces of chocolate (ensure string length is equal).