Crushing bottles

Following crushing some cans with a vacuum, the students were curious to observe the process in action again. Therefore, we crushed an empty fizzy drinks bottle and measured the pressure with the @Pascoscientific pressure sensor. The pressure dropped inside the bottle to almost zero Pascals ( the unit of pressure measurement). A vacuum pump or hand-held vacuum device can be used to remove air from a bottle. The bottle is connected to the vacuum pump or device with a tube, and the air is then pumped out of the bottle, creating a low-pressure environment. As a result, the air pressure inside the bottle decreases, which can cause the bottle to collapse or deform if it is not strong enough to withstand the external air pressure. This process can be used for various purposes, such as preserving food or creating a vacuum-sealed environment for experiments.

Food Tests

During the investigation, the students were surprised by the speed at which starch was converted into sugar by amylase. Recordings taken every 10 seconds showed that the starch had nearly disappeared within a minute.

The test for starch involves placing a small amount of the sample to be tested into a test tube or onto a white tile, and adding a few drops of iodine solution. If starch is present, the solution will turn blue-black.

The test for reducing sugars, such as glucose and fructose, involves mixing the sample with Benedict's reagent and heating it in a water bath. If reducing sugars are present, the solution will change from blue to green, yellow, orange, or red, depending on the amount of reducing sugar present. The greater the amount of reducing sugar, the more intense the colour change.

Assembly Language and Turing Tumbles

 We generated the Fibonacci sequence using Assembly Language using the Little Man Computer and subsequently replicated the process using Turing Tumbles. By examining the methods used, we identified both similarities and differences between the two approaches.

Test for Hydrogen

 When a small amount of magnesium ribbon is added to hydrochloric acid, it produces a significant amount of hydrogen gas in the test tube. When the test tube is turned horizontally and a flame is brought near its mouth, the resulting sound is the characteristic "squeaky pop" of hydrogen gas combustion.

Eyes and Cameras and Light

Studying the human eye involves understanding the functioning of traditional film cameras and the measurement of light levels. In this context, the @Pascoscientific light sensor serves as a useful tool for students. By comparing the perceived brightness of a classroom to the significantly lower brightness outside, which is ten times brighter, the sensor helps to illustrate the differences in light levels.

A traditional film camera captures an image by exposing a light-sensitive film to light. The amount of light that enters the camera is controlled by three factors: ISO, aperture, and shutter speed.

ISO is a measure of the film's sensitivity to light. A higher ISO number indicates a more sensitive film, which can capture images in low light conditions but also tends to produce more grainy or "noisy" images. A lower ISO number indicates a less sensitive film, which produces sharper, cleaner images but requires more light.

The aperture is the opening in the lens through which light enters the camera. It is measured in f-stops, which determine the size of the aperture. A smaller f-stop number indicates a wider aperture, which allows more light to enter the camera. A larger f-stop number indicates a narrower aperture, which allows less light to enter the camera.

The shutter speed is the length of time that the camera's shutter remains open to allow light to enter the camera and expose the film. It is measured in fractions of a second, such as 1/60th or 1/1000th of a second. A slower shutter speed, such as 1/60th of a second, allows more light to enter the camera and is ideal for capturing images in low light conditions, but can result in blurred images if the camera or the subject is moving. A faster shutter speed, such as 1/1000th of a second, allows less light to enter the camera but is ideal for capturing fast-moving subjects.

By adjusting the combination of ISO, aperture, and shutter speed, a photographer can control the amount of light that enters the camera and achieve the desired exposure for a given scene. For example, if a scene is very bright, the photographer can use a low ISO, a narrow aperture, and a fast shutter speed to prevent overexposure. Conversely, if a scene is very dark, the photographer can use a high ISO, a wide aperture, and a slow shutter speed to capture more light and avoid underexposure.

The eye and a traditional film camera are similar in that they capture images by controlling the amount of light entering the system. However, there are some critical differences between the two.

In a film camera, the film is exposed to light for a set amount of time, determined by the shutter speed, which controls the duration of the exposure. In the eye, the retina is continuously exposed to light, and the iris, which controls the size of the pupil, adjusts to regulate the amount of light that enters the eye.

Similarly, the aperture of a camera lens controls the amount of light that enters the camera, just as the pupil of the eye adjusts to regulate the amount of light that enters the eye. However, the aperture of a camera lens is fixed, whereas the pupil of the eye can adjust in size to allow more or less light to enter.

A film camera's film speed or ISO determines the film's sensitivity to light. Similarly, the retina's sensitivity to light can vary depending on the amount of light it is exposed to. However, the retina does not have a fixed ISO setting, and its sensitivity can be affected by various factors, including age, health, and environmental conditions.

Overall, while there are some similarities between the eye and a traditional film camera, the mechanisms that control the amount of light that enters the system are quite different.

Crystals of Aluminium Potassium Sulfate

To discover the inner beauty of crystals, you can observe them through a low-power lens or a macro lens on a camera. Doing so will reveal a stunning world of intricate crystal shapes. As an example, observe the Aluminum Potassium Sulfate crystal.

Online Pressure

 Demonstrated pressure online was a bit of a challenge, but I succeeded in doing it in a bowl quite effectively. Running out of hands is the most significant problem.  The depth of water can have a significant effect on pressure. As the depth of water increases, the pressure at that point increases as well. This relationship is known as hydrostatic pressure, and it is the pressure exerted by a fluid due to the weight of the fluid itself.

The hydrostatic pressure is directly proportional to the depth of the fluid, meaning that the pressure increases as the depth of the fluid increases. The formula for calculating the hydrostatic pressure is P = ρgh, where P is the pressure, ρ is the density of the fluid, g is the acceleration due to gravity, and h is the depth of the fluid.

For example, if the depth of water is 10 meters, and the density of water is 1000 kg/m³, the pressure at that depth would be:

P = (1000 kg/m³) x (9.81 m/s²) x (10 m) = 98,100 Pa

This means that the pressure at a depth of 10 meters in water is approximately 98,100 Pascal, which is much greater than the pressure at the water's surface.

The bottle with holes in different depths shows how, with more depth of water, the pressure inceases.

Here's a simple experiment you can do to demonstrate how the pressure increases as the water depth increases:

Materials needed:

• A clear, plastic bottle
• Water
• A ruler
• A pressure sensor or a small balloon

Procedure:

1. Fill the plastic bottle with water.
2. Place the pressure sensor or small balloon into the bottle, making sure it is completely submerged in the water.
3. Use the ruler to measure the depth of the water in the bottle, starting from the surface of the water to the bottom of the bottle.
4. Record the pressure reading on the pressure sensor or observe the expansion of the balloon.
5. Slowly add more water to the bottle, making sure to keep the pressure sensor or balloon submerged in the water.
6. After adding more water, measure the new depth of the water in the bottle and record the new pressure reading on the pressure sensor or observe the new expansion of the balloon.
7. Repeat steps 5 and 6 several times, gradually increasing the depth of the water in the bottle.
8. Compare the pressure readings or the sizes of the balloon at each depth, and note how they increase as the depth of the water increases.

Explanation: As more water is added to the bottle, the depth of the water increases, which in turn increases the pressure at the bottom of the bottle. This increased pressure is caused by the weight of the water above it, which exerts a force on the water at the bottom of the bottle. This force, in turn, causes an increase in the pressure on the pressure sensor or the balloon. By observing the changes in pressure as the depth of the water increases, you can demonstrate how pressure increases with depth in water.

EKG or ECG

Using the @Pascoscientific EKG sensor (ECG) in the UK to look at the electrical voltage from a heartbeat. We could analyse the signal and look at heartbeats before and after exercise

 

Learning Object Orientated Programming

 New programmers find it easiest to pick up object-orientated programming because they don't know any other way of doing it. Some of the key concepts of OOP include encapsulation, inheritance, and polymorphism and students grasp these easily.

Why Calculus

Sometimes I hear, "why do we need to learn this?" What's the point of doing this? Sometimes once something is learnt we can go on to investigate something further - like Calculus.  Calculus is a branch of mathematics that deals with the study of rates of change and the accumulation of small changes. It has been an essential tool in many areas of science and engineering, including physics, engineering, economics, and statistics. The development of calculus is a fascinating story that spans centuries and involves some of the greatest minds in mathematics.

The origins of calculus can be traced back to ancient Greece, where the method of exhaustion was used to calculate the area of a circle. This method involved inscribing polygons inside and outside the circle and, calculating their areas, then using this information to approximate the area of the circle. However, it was in the 17th century that calculus began to take shape as we know it today.

One of the earliest pioneers of calculus was the English mathematician John Wallis, who, in the 1650s, developed a method of finding the area under a curve by dividing it into small rectangles. This method was further developed by the French mathematician Pierre de Fermat, who used it to solve problems in optics.

However, the work of two great mathematicians, Sir Isaac Newton and Gottfried Wilhelm Leibniz, led to the formal development of calculus. Newton, who was English, and Leibniz, who was German, independently developed a calculus system in the 1670s and 1680s. Newton's system was based on his laws of motion, while Leibniz's system was based on the concept of infinitesimals.

The development of calculus was subject to controversy, however. In the years that followed, there was a bitter dispute between Newton and Leibniz over who deserved credit for the invention of calculus. The dispute was fueled by nationalism, as Newton and Leibniz were fiercely patriotic and by personal animosity, as they had a long-standing professional rivalry. The dispute was eventually settled by a committee of the Royal Society, which ruled that both men had independently developed calculus.

Today, calculus is essential in many fields, including physics, engineering, and economics. The development of calculus has been a fascinating story of innovation and discovery, and it stands as a testament to the power of human intellect and ingenuity.

Heating Zinc Oxide

 One of the interesting things about heating Zinc Oxide is how it changes colour to yellow when hot and reverts back to white when cold. The A-Level students found it harder to determine whether Zinc should be a transition metal or not.

Spirometer

Using the @Pascoscientific spirometer and Capstone to measure my students' and my breathing rate and vital capacity. This is so much easier than using the box spirometer and chart recorder. It seems odd to do a biology experiment in Medical Physics. Still, it is interesting to see how much Physics there is in making and designing devices to measure biological systems.

 

Crushing Can

Crushing a can by the removal of air. An oldie but a goodie. The students didn't realise air and air pressure is as powerful as it is.

Engineering Physics

 Students find out that Engineering Physics is fun, looking at gyros, the drinking birds, using a manometer, water held in a glass by paper and a firestarter.

Gay-Lussacs Law

Gay-Lussac's Law: Investigating the relationship between increasing pressure as the temperature increases for a fixed volume of Gas using the @Pascoscientific pressure sensor and the wireless temperature sensor. I tried this with a Bordon gauge but didn't see enough movement. In 1802, he discovered that when a gas is heated, its volume increases at a constant rate. He also found that when a gas is compressed, its temperature also increases at a constant rate. These two discoveries led to Gay-Lussac's Law of Pressure-Temperature, which states that the pressure of a gas is directly proportional to its temperature.

Sunday is for ... drilling out bungs

 Sunday is for ... drilling out bungs and other prep work and for filming

Coloured liquids showing density

Adding different amounts of sugar to water and dying it. Put the most dense at the bottom and then carefully pour the less dense liquids on top one at a time and we get pretty layers which diffuse together over time

 

Too much time on Practicals

It used to take ages to set up the circuit then, record some values and then graph them. I don't have time for this, so for the properties of resistors and bulbs and diodes the @pascoscientific voltage current sensor records everything in seconds and plots them. Perfect.

 

Whoosh Bottle

A-Level Chemistry one of the properties of Alcohol is that it burns - No far better get out the whoosh bottle and fill it with a bit of alcohol, shake and then ignite. Much more fun, and then lots of discussion on rockets.

fossil fish

Looking at a prehistoric fish fossil under a low-power microscope. Very little has changed in these millions of years. The students found this one more interesting than the ammonites

The not given formulae

 Just when the students thought they had learnt all the rules in the A level Maths book, I gave them even more, followed by the 1/2 angle formula - all derived from the formulae they had learnt - but they weren't happy.

Nylon Rope Trick

Everyone has a favourite experiment, and this is one of mine. The look on the student's faces when the nylon is pulled from the interface.

Pour 5 cm3 of the aqueous diamine solution into a 25 cm3 beaker. Carefully pour 5 cm3 of the cyclohexane solution of the acid chloride on top of the first solution so that mixing is minimised. This is because the oil floats on the water layer. Do this by pouring the second solution down the beaker's wall or a glass rod.

The cyclohexane will float on top of the water without mixing.

Place the beaker below a stand and clamp it. A greyish film of nylon will form at the interface.

Pick up some of this with tweezers and lift it slowly and gently from the beaker. It should draw up behind it a thread of nylon.

Pull this over the rod of the clamp so that this acts as a pulley.

Continue pulling the nylon thread at a rate of about half a metre per second. It should be possible to pull out several metres.

The thread will be coated with unreacted monomer and maybe a narrow, hollow tube filled with monomer solution. Wearing disposable gloves is essential.

Making a salt from an insoluble metal oxide

Copper sulfate is often made because of its colour, but making white salts is just as good, just more difficult for the students to visualise, as the solution is not coloured. Therefore making Zinc Chloride is a bit more of a challenge. 

To make a salt from an insoluble metal oxide and an acid, the metal oxide must be reacted with the acid to produce a salt and water. The reaction can be represented by the following equation:

Metal oxide + Acid → Salt + Water

For example, if the metal oxide is magnesium oxide (ZnO) and the acid is hydrochloric acid (HCl), the reaction would be:

ZnO + 2HCl → ZnCl2 + H2O

In this reaction, the salt produced is magnesium chloride (ZnCl2).

 

Magnetic Field Strength

Investigating how the magnetic field strength changes as a probe is passed between two magnets, using @pascoscientific a rotatory motion sensor with a magnetic probe attached to it.

 

Model of a cell

A cell contains several structures, including:

1. Nucleus - The cell's control centre, containing DNA and regulating cell activity.

2. Endoplasmic reticulum (ER) - A network of membranes involved in protein synthesis and lipid metabolism.

3. Golgi apparatus - A stack of flattened membranes that modify, sort, and package proteins and lipids for transport to other parts or outside the cell.

4. Mitochondria - The cell's powerhouse, responsible for producing energy through cellular respiration.

5. Lysosomes - Small, spherical structures that contain digestive enzymes and break down waste and cellular debris.

6. Vacuoles - Large, fluid-filled organelles that store materials such as water, salts, and pigments.

7. Microfilaments and Microtubules - Tiny protein fibres that help maintain cell shape and support the cellular movement.

8. Peroxisomes - Small organelles containing enzymes involved in metabolic processes, including the breakdown of fatty acids and detoxifying harmful substances.