A Level Physics Topic by Topic | Hooke's law of Elasticity and Inelastic Materials

Hooke's law is an important concept in many fields, including engineering, where it is used to design and analyze systems such as suspension systems in vehicles and the springs in mechanical clocks. It is also used in studying the behaviour of materials under stress and in designing structures and machines that rely on the elastic properties of materials.or compress a spring is directly proportional to the displacement or deformation of the spring. In other words, the greater the force applied to a spring, the greater the displacement or deformation of the spring will be.

When two or more springs are connected in series, the total force required to stretch or compress all of the springs is equal to the sum of the forces required to stretch or compress each spring individually. The total displacement or deformation of the series of springs is equal to the displacement or deformation of the first spring plus the displacement or deformation of the second spring, and so on.

When two or more springs are connected in parallel, the total force required to stretch or compress all of the springs is equal to the force required to stretch or compress a single spring with the same spring constant as the parallel combination. The total displacement or deformation of the parallel springs is equal to the displacement or deformation of any one of the springs.

Hooke's law is an important concept in many fields, including engineering, where it is used to design and analyze systems such as suspension systems in vehicles and the springs in mechanical clocks. It is also used in studying the behaviour of materials under stress and in designing structures and machines that rely on the elastic properties of materials.

Better Titration

 The @Pascoscientific drop counter. It does titrations really fast and accurately so this is ideal for revision ( some mock exams coming up) and produces great data for lots of calculation practice 

First Analog Computing Lesson

Analog computers can be implemented using various hardware components, including resistors, capacitors, inductors, and operational amplifiers. These components can be used to build circuits that perform mathematical operations, such as addition, subtraction, multiplication, and division. The Lesson Plan can be found at Analog computing

Proof by contradiction

 Proof by contradiction, also known as indirect proof or reductio ad absurdum, is a method of proof in which a claim is shown to be true by showing that the opposite of the claim leads to a contradiction or absurdity.

Experimenting with spintronics

 

Time to play and experiment with spintonics from @UpperStoryCo and write some lesson plans for it. Discovering it is not only good for electronics but its quite good for mechanics and problem solving as well.

Resistivity

The resistance of a wire is directly proportional to its length. This means that as the length of a wire increases, its resistance also increases. This relationship can be described by the equation:

R = ρL / A

where R is the resistance of the wire, ρ is the resistivity of the material, L is the length of the wire, and A is the cross-sectional area of the wire.

The reason for this relationship is that as the length of a wire increases, the number of collisions between the electrons and the atoms of the wire also increases. These collisions cause resistance and make it more difficult for the electrons to flow through the wire. As a result, the resistance of the wire increases as its length increases.

It's important to note that this relationship holds true only for a given material and cross-sectional area. If the material or cross-sectional area of the wire is changed, the relationship between length and resistance will also change.

Resistivity is a measure of the resistance of a material to the flow of electric current. It is typically denoted by the symbol ρ and is expressed in units of ohm-meters (Ω*m).

In general, materials that are good conductors of electricity have low resistivity, while materials that are poor conductors have high resistivity. For example, metals such as copper and aluminium have low resistivity and are commonly used in electrical wiring because they allow an electric current to flow easily. On the other hand, materials such as rubber and glass have high resistivity and are often used as insulation because they resist the flow of electric current.

The resistivity of a material is related to its electrical conductivity, which measures how easily a material allows electric current to flow. The relationship between resistivity and conductivity is given by the equation:

conductivity = 1 / resistivity

This means that materials with high resistivity have low conductivity and vice versa.

 

Ball drop

To record the motion of a ping pong ball being dropped against a black background in a totally dark room using a camera and flash gun set at 15 Hz (15 flashes per second), you will need to follow these steps:

1. Set up your camera on a tripod or other stable surface, making sure it is pointed at the area where you will be dropping the ping pong ball.

2. Set the camera to manual mode, and adjust the exposure settings to ensure that the image is well-exposed when the flash fires. You may need to experiment with different settings to get the right balance.

3. Set up the flash gun on a separate stand or tripod, making sure it is pointed at the area where you will be dropping the ping pong ball.

4. Set the flash gun to strobe mode, and adjust the flash frequency to 15 Hz (15 flashes per second).

5. Turn off any other light sources in the room, so that the room is completely dark.

6. Drop the ping pong ball from a height above the camera and flash, making sure that it falls within the field of view of the camera.

7. Start the camera's continuous shooting mode, and let it run for a few seconds as the ping pong ball falls.

8. Review the images on the camera's display or on a computer to see the motion of the ping pong ball as it falls.

By using a flash set to strobe at a high frequency and shooting in a completely dark room, you will be able to capture the motion of the ping pong ball as it falls, showing the effects of gravity on its motion.

Making Crystals

 One of my most enjoyable experiments is making crystals from solutions. Sometimes we manage to produce some large, well-formed crystals when the students make copper sulfate. Even the small ones look good under the microscope.

Microtome

Dissections mean opportunities to create slides of what the students are looking at and learn how to slice very thinly so we can see what is going on at the cellular level using a Microtome. A microtome is a scientific instrument used to cut very thin slices of material, known as sections. These sections can then be mounted on a microscope slide and viewed under a microscope for further analysis.

Microtomes are commonly used in a variety of scientific fields, including biology, pathology, and materials science. In biology, microtomes are often used to prepare sections of plant or animal tissue for microscopy. In pathology, microtomes are used to cut sections of human or animal tissue for histological examination. In materials science, microtomes are used to cut sections of materials for microscopic examination to study their structure and properties.

There are several types of microtomes, including manual microtomes, motorized microtomes, and cryomicrotomes. Mine is really basic. Manual microtomes use a hand crank to advance the material through a blade, while motorized microtomes use an electric motor to do the same. Cryomicrotomes are used to cut frozen sections of material, such as tissue that has been preserved in cryogenic fluids.

 

Calculating Vectors with Pasco Capstone

 Using the ball launcher on the @Pascoscientific smart cart and then analysing the video footage and putting in the vectors to show that the x and y vectors are independent and a classic quadratic graph for the flight of the ball.

Amber

 Really old-fashioned static electricity using Amber to pick up pieces of paper. The more you clean and polish it the dirtier it becomes

Electrostatics

 Electrostatics - there is nothing like a Wimshurst machine to demonstrate electrostatics: hand powered and can be done very slowly - does all the tricks of a Van de Graaff Generator and watch the gold leaf electroscopes that are within  a few metres respond

The mass of a volatile liquid

 Determining the volume of a mass of a volatile liquid at 100 Celcius. Quite a tricky experiment to get right. Patience is required to get the apparatus hot enough. But the idea of how much bigger a gas is comes through

Matrices

 Learning about Matrices. Finding determinants, calculating inverse Matrices and trying to solve 3 variable simultaneous equations. A level further Maths

GCSE Optics

 Looking at how a flame is turned upside down as the image passes through a lens and reflected on a screen at the far end. Using the optics bench with the scale built in we quickly worked out the relationships to achieve this

Dissecting a Lamb Pluck

 Dissecting a lamb pluck, inflating the lungs, examining the heart, and looking at the diaphragm and the liver. The lungs differ from what the books show,  in and the hole to the lungs before the bronchioles.

Hydrocarbon burning

 

@chemix diagram helped the students go from the design to the reality in minutes.

Terminal velocity

A @pascoscientific rotary motion sensor measuring a thin string attached to different shaped weights. The tube is 2m long and filled with water can determine the max velocity. The mass is wrapped tin the same mass of different shapes of plasticine to see the effect of streamlining

Radial Electric Field

 Observing a radial electric field. Excellent results are achieved using just one or two turns on the Wimshurst machine and thick gauge wire with the castor Oil and Semolina

Ideal Gas

 

Investigating the relationship between temp and pressure using the @pascoscientific ideal gas kit and Capstone. The students clearly saw that as the volume halved, the pressure doubled, and the temperature spiked.

Naming Organic Chemistry

 It's glycine made from @snatoms, but its IUPAC name is much more difficult to work out

Centre of Mass Experiment

 An opaque plastic container on an inclined plane. Some have a high centre of mass and some have a low centre of mass. Working out which is which using an inclinometer app on a phone. Making Phones useful in the lab and devising experiments to test out

Old and New Technology

 Using old and new technology together, with a tickertape recording and the @pascoscoientific smart cart generating a realistic record of the journey down the track

Shapes of molecules across a period

Looking at the shapes of molecules changing as we move across a period. Fun naming some of the shapes and working out the angles, then comparing Methane, Ammonia and Water and why the angles change
 

Respirometer

 Investigating respiration using the respirometer to measure the uptake of oxygen from some germinating cress seeds. Its going to take a while so the next candidate for a time lapse

Reversible reactions

 Take blue hydrated copper sulfate heat it to make white anhydrous copper sulfate. Add a little water observe the colour change and the het given out. Heat the blue copper sulfate and return to anhydrous copper sulfate and repeat. Some repeated it four time and were convinced it could go on for ever.

A Level Computing

 

A level Computing and I got out the #turingtumbles. I don't think I have ever seen the students so engaged. The lesson ended and they all stayed on solving problems of logic

More Spectral line

 Using the @pascoscientific spectrometer to show the same spectral lines as the simple spectrometer. the students were more convinced that the spectrometer was showing the right thing. Much easier to use and see what is going on

Spectral Lines

Using a very cheap and simple spectroscope the students with the help of the camera could observe and record the spectral emission lines from different sources

 

Comparing the absorption of Heat

Comparing the absorption of Heat by heating two plates, one black and one silver with a light bulb and then comparing the heat loss when the bulb is off using @Pascoscientific temperature sensors and Capstone

Iodine in Cyclohexane

 A small crystal of Iodine in some water and a layer of cyclohexane above. A little shake and the gorgeous colour of Iodine is seen in the organic layer. This still has the wow effect.

Ticker Tape Timing

 

With all the wonders of electronic sensors sometimes using some basic equipment like ticker tape timers to look at acceleration and how the lengths of tape get longer in the same time period aids the understanding.

Infrared led

An invisible infrared led shines brightly when we take a photo of it for the Planks constant apparatus 

Biology Virus

 Its certainly easier teaching about viruses these days. The students know about them and how to stop them. They still struggle with how they get into cells and what they do there however

The Nylon Rope trick

 The nylon rope trick is one of my favourite experiments and also using @Snatoms to show the students what is going on at that oil water interface

Pasco and Lego

 Two of my favourites, Lego and @Pascoscientific and working together. Creating different types of carts for use with a motion sensor. Trying different wheels and wheel arrangements for different surfaces. Which is the most effective for different terrains

Probability

 Maths is having fun with the dice tower and 120 dice trying to see if more dice gives the 1/6 ratios, or whether 1200 dice was better. Conclusion we needed to go much bigger - very much bigger

Locktronics is an electricity winner

 So easy from diagram on the board to a completed and working circuit using Locktronics from @MatrixTSL The students can seem to get through twice as many experiments in the time and more importantly with greater understanding

Ready to do a titration

 I have started using automatic dispensing pipettes with the students when setting up titrations. Why use the pipettes with a bulb when the students aren't good with them and use these which are more accurate and faster.

yeast bubbling

 Anaerobic respiration demonstrated by yeast making carbon dioxide in some orange juice and in bread

Proving the theorems

 Sometimes knowing the theorem is not enough. You have to be able to prove it and justify the facts to be true.