Pendulum Clock Aim: To determine the relationship between the drop angle of a bob and the time it takes for the pendulum to stop swinging Focus Question: Can you make a Pendulum clock? A pendulum clock is a special type of old clock that was used before clocks were electronic. They work using a swinging pendulum that the user would wind up, and then the pendulum would swing. A pendulum continues to swing due to its continuous conversion between gravitational potential energy and kinetic energy. An object that continues to switch its energy between potential and kinetic is called a harmonic oscillator. Even though as the pendulum continues to swing energy is lost to air resistance, the bob take the exact same amount of time to complete one swing, no matter how much energy it has. This is simply because, with a higher angle comes a greater distance, but also a quicker swing time. As energy is lost and the angle becomes smaller, the pendulum also swings slower. This means that the period of the swing remains the same. The pendulum clock works around its swinging pendulum. Every time the bob completes a full swing, or returns to the point it was dropped from, it turns the second gear once, which turns the minute gear at 1/60 of the speed and therefore the hour hand at 1/60 the speed of the minute hand. In our experiment we set up a pendulum using a bob on a 60cm string hanging from a clamp attached to a retort stand. The setup can be seen in the scientific diagram below. We discovered that the oscillation of the pendulum, when dropped from an angle of 45 degrees, caused the pendulum to swing back and forth continuously for over 30 minutes. The fact that this single measurement took so long meant that we were unable to record any other angles.
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Lemon Battery Experiment Aim: To make a battery using fruit and metal Keywords: Cathode: A negatively charged electrode that all electrons enter the electrical device through. Anode: A positively charged electrode through which all electrons leave the electrical device Electrolyte: Substances within the body which contain ions that help the body perform different functions such as contracting muscles and regulating the heartbeat. Focus Question: How Many Oranges does it take to Charge and IPhone? Approx. 2 380 orange slices, Approx. 595 oranges. In order to calculate the amount of oranges required to charge an IPhone, we must first look at the amount of energy required to bring the IPhone battery up to 100%. The IPhone 6, to be fully charged, requires 10.5 watt hours, which is equal to 37 800J. From our experiment, we know that the amount of energy that produced by the orange was 853J. Now, if we divide 37 800 by 853, we get approx. 44.3 oranges. This number is quite odd, as the numbers above following the focus question came from a video explaining this very question, and they suggest that we would need over 13 times the amount of oranges as the amount that I calculated. In this lesson we performed the ‘Lemon Battery Experiment’ to see whether we could make a battery out of fruit and metal. The two different metals we used were copper and zinc, which acted as our anode (positive side to the battery) and our cathode (negative side) respectively. We measured the amount of energy that flowed through a lemon, potato and an orange, and ordered them from the least energy flow to the most. How does the ‘Lemon Battery Experiment’ work? In five dot points:
From the above table you can see that the potato had the least amount of energy on 823J, with the orange in the middle with 853J, and the lemon in first, beating the orange by over 50J, on 906J. Lesson Summary
Energy TransformationsAim: To investigate energy and electricity transformations. In this lesson, we participated in four small experiments that showed energy transformations. Here are our findings: The first experiment was the spinning of a dynamo to make a light bulb activate. This demonstrated how the kinetic motion energy being input by the person turning the dynamo, transformed into electrical kinetic energy as it ran through the wires, before being released through the activated light bulb as light and thermal kinetic energy. The second experiment was to investigate how an electrical input can make a bell ring. Our findings discovered that the electrical energy, when input into the bell, transformed into motion and sound energy, which caused the bell to jump around and to produce a very loud ringing sound. Our third experiment was to measure the amount of energy (measured in joules) collected by solar panels when light energy, produced by different voltages of electrical energy, is input. We measured the amount of output energy from 2 through to 12 volts of input energy. We found that each time the amount of output energy collected increased, on average, by 23.17J. The increase in input energy corresponding with the increase of output energy, evidently showed the transformation between the electrical input energy, to the light energy, to then be collected as electrical energy. Our final experiment was to use a renewable energy kit to show energy transformations between electrical energy and, light, wind and sound energy. We used wires to connect various ports on the kit to ports on a battery to activate the fan, the LED and regular light bulb, and the fan. This demonstrated how the chemical potential energy stored within the battery transformed into electrical energy, before being output as either wind, light or sound energy. Lesson Summary:
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