Link to Sound properties from Rubber band instruments lesson plan.
Link to Sound properties from rubber band instruments training video.
Sound and music are universally important in everyday life, and it can be fun and interesting to study sound in a science class to determine who and why instruments work the way they do when making music. In this activity, using rubber bands allows for simple instruments to be created, and then have students systematically determine what needs to be done in order to change the pitch of the sound made by stretched rubber bands.
Any type of wave has three main quantities - wavelength, frequency and wave speed. This experiment allows us to change the wavelength (the stretch of the rubber band), the frequency (by changing the tension in the rubber band), while having a constant speed of sound of around 330 meters/second. There is a mathematical relationship between these three:
wave speed = (wavelength)x(frequency), or v = λf
Enjoy making a homemade instrument from rubber bands, and get ideas from the lesson plan or from the video.
Saturday, December 28, 2019
Physics Activity - Simple harmonic motion (Oscillations) using string and rubber bands
Link to Simple harmonic motion lesson plan.
Link to Simple harmonic motion training video.
Simple harmonic motion is a type of periodic motion, where there is a restoring force that is directly dependent on the displacement of the system. For example, for something like a spring, the force needed to stretch a typical spring depends on the stretch distance; if you stretch a spring 5 centimeters with some force, then you will need twice the force to stretch and hold a spring 10 centimeters, and three times the force to stretch and hold the spring with a 15 centimeter stretch. This is Hooke's law, where Force = (constant)(stretch distance), or F = kx. The constant k is called the spring constant, and it basically measures how stiff a spring is. This same law generally works for rubber bands, if one does not have springs available.
This experiment is relatively simple to do with rubber bands (to replace springs) and strings (for a pendulum). Teachers and students can make measurements of the periods of both oscillating springs that are bouncing up and down when there are masses hung from the rubber bands and swinging pendulums. There is a separate experiment for figuring out details of a pendulum you may want to do before this experiment.
The period of a bouncing rubber band as a function of the mass hung on the rubber band gives a square root relationship when graphed. This is identical to the graph for a pendulum of the period as a function of the length of the pendulum, which is also a square root graph. These are shown in the training video. This can show the general behavior of any system that is simple harmonic in it vibrations - they are all the same mathematically. There is a video for advanced students showing the mathematics for an oscillating spring, as well as a video for the mathematics of a swinging pendulum at small angles. The mathematical analysis will be identical for these two examples, which is measured in this experiment.
Have fun with the simple harmonic motion experiment and training video.
Link to Simple harmonic motion training video.
Simple harmonic motion is a type of periodic motion, where there is a restoring force that is directly dependent on the displacement of the system. For example, for something like a spring, the force needed to stretch a typical spring depends on the stretch distance; if you stretch a spring 5 centimeters with some force, then you will need twice the force to stretch and hold a spring 10 centimeters, and three times the force to stretch and hold the spring with a 15 centimeter stretch. This is Hooke's law, where Force = (constant)(stretch distance), or F = kx. The constant k is called the spring constant, and it basically measures how stiff a spring is. This same law generally works for rubber bands, if one does not have springs available.
This experiment is relatively simple to do with rubber bands (to replace springs) and strings (for a pendulum). Teachers and students can make measurements of the periods of both oscillating springs that are bouncing up and down when there are masses hung from the rubber bands and swinging pendulums. There is a separate experiment for figuring out details of a pendulum you may want to do before this experiment.
The period of a bouncing rubber band as a function of the mass hung on the rubber band gives a square root relationship when graphed. This is identical to the graph for a pendulum of the period as a function of the length of the pendulum, which is also a square root graph. These are shown in the training video. This can show the general behavior of any system that is simple harmonic in it vibrations - they are all the same mathematically. There is a video for advanced students showing the mathematics for an oscillating spring, as well as a video for the mathematics of a swinging pendulum at small angles. The mathematical analysis will be identical for these two examples, which is measured in this experiment.
Have fun with the simple harmonic motion experiment and training video.
Physics Activity - Ohm's law for basic circuits
Link to Ohm's law lesson plan.
Link to Ohm's law training video.
*Note that this experiment/demonstration activity requires some specialized equipment. A teacher would need batteries, wire or cables, ideally a few resistors, and some type of ammeter (measures electric current). If you do not have access to such equipment, especially an ammeter, if you have small light bulbs or LEDs, one can get a measure of electric current by the brightness of the bulbs.
Ohm's law is a basic rule for resistor circuits. One can make a simple circuit just by connecting a wire to some device that has resistance, and then touching the wires to the two terminals of a battery. Electricity will flow through the device, which should then begin producing heat. If you have light bulbs, those could serve as resistors, and the brightness of the light will indicate the amount of electric current flowing through the resistance.
This experiment has students do two procedures. The first has a fixed resistance, which could be a resistor or a light bulb, and then vary the voltage. One would need multiple batteries, so that you could double, triple, and quadruple the voltage if you had two, three and four batteries connected together in series. The light bulb should increase in brightness each time a battery is added, since the current increases linearly with the voltage.
The second procedure would use a fixed voltage, say just one battery every time, but with a different resistance each time to see how that affects the current. One could add light bulbs in series each time, and for every light bulb added, the brightness in each bulb should decrease, since increasing the resistance will lower the current. If you happen to have an ammeter, a direct measure of amperes of current could be made and graphed.
The results of these two experiments allows Ohm's law to come out:
electric current = voltage/resistance, or I = V/R
Have fun with simple circuits and Ohm's law.
Link to Ohm's law training video.
*Note that this experiment/demonstration activity requires some specialized equipment. A teacher would need batteries, wire or cables, ideally a few resistors, and some type of ammeter (measures electric current). If you do not have access to such equipment, especially an ammeter, if you have small light bulbs or LEDs, one can get a measure of electric current by the brightness of the bulbs.
Ohm's law is a basic rule for resistor circuits. One can make a simple circuit just by connecting a wire to some device that has resistance, and then touching the wires to the two terminals of a battery. Electricity will flow through the device, which should then begin producing heat. If you have light bulbs, those could serve as resistors, and the brightness of the light will indicate the amount of electric current flowing through the resistance.
This experiment has students do two procedures. The first has a fixed resistance, which could be a resistor or a light bulb, and then vary the voltage. One would need multiple batteries, so that you could double, triple, and quadruple the voltage if you had two, three and four batteries connected together in series. The light bulb should increase in brightness each time a battery is added, since the current increases linearly with the voltage.
The second procedure would use a fixed voltage, say just one battery every time, but with a different resistance each time to see how that affects the current. One could add light bulbs in series each time, and for every light bulb added, the brightness in each bulb should decrease, since increasing the resistance will lower the current. If you happen to have an ammeter, a direct measure of amperes of current could be made and graphed.
The results of these two experiments allows Ohm's law to come out:
electric current = voltage/resistance, or I = V/R
Have fun with simple circuits and Ohm's law.
Physics Activity - Properties of a Pendulum
Link to Properties of a Pendulum lesson plan.
Link to Properties of a Pendulum training video.
A pendulum is a useful, simple device for physics experiments. It is easily constructed with nothing more than a piece of string of any length, and any small weight to tie on the end so that there is some tension in the string and gravity can make it oscillate back and forth.
A pendulum was the first type of mechanical clock, dating back to the time of Galileo and Newton. It exhibits periodic motion (and approximately simple harmonic motion), and experiments can be done to determine what parameters or factors go into the time it takes for one full swing, which is the period of the pendulum. Those parameters that can be tested by students include:
- the length of the string
- the mass hanging on the string
- the initial angle you start the pendulum's motion
- if you have access to a computer and the Internet, a computer simulation can be used to vary the
strength of gravity, which also affects the period of a pendulum.
This is a nice experiment that can also be used to demonstrate the approach a scientist takes when taking on an unknown phenomenon. If students know nothing about what each parameter has on the timing of a pendulum, and most will not know anything about it, they can collect data, make a graph to see the relationships, and then develop their own math formula (an empirical formula) for the pendulum. These students math models can then be compared to what the accepted formula is - but to a student, they are the scientist and they are making a discovery for themselves, rather than just reading about a pendulum. There is a video for those who want to see the mathematical analysis for the tension in a pendulum's string as it swings. There is a video for those who want to see the mathematical analysis for the oscillation of a pendulum through a small angle (simple harmonic motion).
Give it a try! Have fun with determining the properties of a pendulum.
Link to Properties of a Pendulum training video.
A pendulum is a useful, simple device for physics experiments. It is easily constructed with nothing more than a piece of string of any length, and any small weight to tie on the end so that there is some tension in the string and gravity can make it oscillate back and forth.
A pendulum was the first type of mechanical clock, dating back to the time of Galileo and Newton. It exhibits periodic motion (and approximately simple harmonic motion), and experiments can be done to determine what parameters or factors go into the time it takes for one full swing, which is the period of the pendulum. Those parameters that can be tested by students include:
- the length of the string
- the mass hanging on the string
- the initial angle you start the pendulum's motion
- if you have access to a computer and the Internet, a computer simulation can be used to vary the
strength of gravity, which also affects the period of a pendulum.
This is a nice experiment that can also be used to demonstrate the approach a scientist takes when taking on an unknown phenomenon. If students know nothing about what each parameter has on the timing of a pendulum, and most will not know anything about it, they can collect data, make a graph to see the relationships, and then develop their own math formula (an empirical formula) for the pendulum. These students math models can then be compared to what the accepted formula is - but to a student, they are the scientist and they are making a discovery for themselves, rather than just reading about a pendulum. There is a video for those who want to see the mathematical analysis for the tension in a pendulum's string as it swings. There is a video for those who want to see the mathematical analysis for the oscillation of a pendulum through a small angle (simple harmonic motion).
Give it a try! Have fun with determining the properties of a pendulum.
Astronomy or Physics Activity - It can be as simple as looking up (in a night sky) for Meteor Showers
This particular activity does not require any lesson plan. It is really a reminder for us to not forget to every so often step back, take a deep breath, and enjoy and stand in awe of the natural world. But this includes looking up at night to observe the vastness and wonders of space.
For those teachers who want to ever do anything with astronomy, and have occasional access to the Internet at training sessions or other venues, this link will allow you to observe the earth in its orbit and see dates when we will have meteor showers. The site shows the earth as it passes through dust and rock clouds that are also in orbit around the sun, and intersect earth's orbit.
Take a look if possible, and write down/keep track of dates in the next year, and then you can suggest those evenings to students so they can go out in the evening and try to search for meteors! They can try to count how many they see, and also track which direction they are moving. This opens conversations and discussions in class as to what meteors are, why we have showers on occasion (and even if you do not have computers in your school, sketch out for students what you saw on this site so they understand why we have meteor showers as we pass through the clouds), the nature of orbits of countless objects around the sun besides the planets, the nature of air friction and why even rocks form 'fireballs' because they move so fast in the air and generate so much heat, and even how the solar system formed.
For those teachers who want to ever do anything with astronomy, and have occasional access to the Internet at training sessions or other venues, this link will allow you to observe the earth in its orbit and see dates when we will have meteor showers. The site shows the earth as it passes through dust and rock clouds that are also in orbit around the sun, and intersect earth's orbit.
Take a look if possible, and write down/keep track of dates in the next year, and then you can suggest those evenings to students so they can go out in the evening and try to search for meteors! They can try to count how many they see, and also track which direction they are moving. This opens conversations and discussions in class as to what meteors are, why we have showers on occasion (and even if you do not have computers in your school, sketch out for students what you saw on this site so they understand why we have meteor showers as we pass through the clouds), the nature of orbits of countless objects around the sun besides the planets, the nature of air friction and why even rocks form 'fireballs' because they move so fast in the air and generate so much heat, and even how the solar system formed.
Friday, December 27, 2019
Astronomy, Maths or Physics Activity - Scaling the size of the solar system
Link to Scaling the size of the solar system activity
A 'scale model' of something is a replica, either larger or smaller than the actual object, where all the parts of the object have the same proportionalities in size. So if you wanted to make a scale model of a house, if the doors are twice as tall as the windows, then in the model the small doors would have to be twice as tall as the small windows.
The solar system is SO large that it is very difficult for both teachers and students to comprehend - we don't know what millions or billions of kilometers look like between the planets and sun. But to gain some appreciation for how vast our solar system is, we can have students figure out how to make a scale model of the solar system.
This lesson walks through how to get the proportionalities between the distances from planet to planet, based on the size of the sun. By choosing some small ball or rock as the sun, and measuring how wide the ball or rock is with any type of ruler, students can determine the proper ratios of distances between planets using the sun's diameter as a scale. You will need to do this outside, because students will need to measure out dozens of meters for the outer planets! But this type of activity allows everyone to begin to have some insight about the relative distances from planet to planet; and this process of scaling can be used any time a teacher or student wants to understand the relative sizes or positions of any object or system, as well as using scales to make accurate maps. Scaling is also good math practice for converting between different units, such as centimeters to meters to kilometers; it is all about fractions, ratios and proportions.
Have fun with the Scaling the size of the solar system lesson!
A 'scale model' of something is a replica, either larger or smaller than the actual object, where all the parts of the object have the same proportionalities in size. So if you wanted to make a scale model of a house, if the doors are twice as tall as the windows, then in the model the small doors would have to be twice as tall as the small windows.
The solar system is SO large that it is very difficult for both teachers and students to comprehend - we don't know what millions or billions of kilometers look like between the planets and sun. But to gain some appreciation for how vast our solar system is, we can have students figure out how to make a scale model of the solar system.
This lesson walks through how to get the proportionalities between the distances from planet to planet, based on the size of the sun. By choosing some small ball or rock as the sun, and measuring how wide the ball or rock is with any type of ruler, students can determine the proper ratios of distances between planets using the sun's diameter as a scale. You will need to do this outside, because students will need to measure out dozens of meters for the outer planets! But this type of activity allows everyone to begin to have some insight about the relative distances from planet to planet; and this process of scaling can be used any time a teacher or student wants to understand the relative sizes or positions of any object or system, as well as using scales to make accurate maps. Scaling is also good math practice for converting between different units, such as centimeters to meters to kilometers; it is all about fractions, ratios and proportions.
Have fun with the Scaling the size of the solar system lesson!
Physics Activity - Paper airplanes and the effect of shape-design on performance
Link to Paper airplanes activity.
See the lesson at the Kakuma Refugee Camp, in Kenya.
With only paper, folding into a wide variety of paper airplane designs can set up a fun round of experiments and contests for students to enjoy, but also learn about the concept of design and aerodynamics. This can be done in conjunction with the air friction experiment, as it shows the effect shape and cross sectional area has on air friction and movement through the air. On the website, click on any design option and it will show frame by frame photos of the folding needed, or one can print out the design instructions to give to students. There are videos showing the folding, as well, if you have Internet access.
Experiments can be done where each student does a different design, and then you can test them for flying distance or time in the air. Students should keep measurements for all the designs, so they can all be compared to one another. But other factors or parameters can be included in these tests. For example, for the same design, try throwing them at different launch angles to see if that has an effect. Use something like paperclips to vary the weight of the airplane, and see if that changes anything about the flight. Instead of a full sheet of paper, make the same designs with only a half sheet, or some other fraction of a sheet of paper. Does the size and weight make a difference in flight results? This is all experimentation, and this is a process scientists and engineers would do when they are considering different designs of experiments or of actual airplanes.
However you choose to approach the activity, it is recommended that you have time at the end where you give students paper, and let them get creative - let them think of variations on what they just did, try their own design and test it, and then discuss with the class why they thought certain design features might work. It is a lot of fun to see what students come up with and why! Often they will come across and 'discover' on their own some relevant aerodynamic principles.
Have fun with the paper airplane activity.
See the lesson at the Kakuma Refugee Camp, in Kenya.
With only paper, folding into a wide variety of paper airplane designs can set up a fun round of experiments and contests for students to enjoy, but also learn about the concept of design and aerodynamics. This can be done in conjunction with the air friction experiment, as it shows the effect shape and cross sectional area has on air friction and movement through the air. On the website, click on any design option and it will show frame by frame photos of the folding needed, or one can print out the design instructions to give to students. There are videos showing the folding, as well, if you have Internet access.
Experiments can be done where each student does a different design, and then you can test them for flying distance or time in the air. Students should keep measurements for all the designs, so they can all be compared to one another. But other factors or parameters can be included in these tests. For example, for the same design, try throwing them at different launch angles to see if that has an effect. Use something like paperclips to vary the weight of the airplane, and see if that changes anything about the flight. Instead of a full sheet of paper, make the same designs with only a half sheet, or some other fraction of a sheet of paper. Does the size and weight make a difference in flight results? This is all experimentation, and this is a process scientists and engineers would do when they are considering different designs of experiments or of actual airplanes.
However you choose to approach the activity, it is recommended that you have time at the end where you give students paper, and let them get creative - let them think of variations on what they just did, try their own design and test it, and then discuss with the class why they thought certain design features might work. It is a lot of fun to see what students come up with and why! Often they will come across and 'discover' on their own some relevant aerodynamic principles.
Have fun with the paper airplane activity.
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