STEAM with Dad

Today I am going to tell you what lenses are, how they work and many more things. Let's dive in! A lens is an optical device with at least one curved surface to focus or disperse light beams by means of refraction.  Some of you may be wondering why I am talking about lenses. Well, it is because of how common they are, for example lenses are used in microscopes, telescopes, cameras, and even your Granma's reading glasses. So, now that you know what lenses are I can teach you how they work.  In the previous blog post we saw the light moving from air to water. The surface between the two media was flat but the surface of the lens is curved. We can use Snell's law if we think of a curve as  a big series of tiny flat lines one after the other.  For example in my diagram below I have drawn a plano-convex lens and three light rays. First, they go through the flat face of the lens. Snell's law predicts that they will go straight through because the sine of 0 degrees is 0 The...

In the previous blog post I talked briefly about Snell's law, however, I couldn't cover this topic due to the fact that I did not know the maths required. Guess what! I know them now. Well, at least at a basic level. Let's get into it. The thing I needed to learn was the "sine" of an angle. The cool thing is that in a right-angle triangle, like the one below, if you take one side of the right-angle ("a" below) and divide it by the opposite side of the right-angle ("h" below) then you get same number no matter what size the triangle is.  As you can see a1/h1 is 0.708 and so is a2/h2 almost perfectly. This number is called the sine of the angle O1. By the way "h" is called the hypotenuse ... who came up with that name! I have learnt how to work with a table of sines to calculate the sine of an angle. I use this one from NASA . So, now we can understand Snell's law. It predicts how much the light will bend when it changes media based...

In the previous post I talked about the human eye and how it uses refraction. Today we will go into more detail about refraction. Refraction is light bending when it changes medium as it travels. This is what causes a pen to look like it's bending when you put it in water. Sometimes, light bends inwards and sometimes bends outwards depending on the speed of each medium. The fastest speed the light can go at is in vacuum which is a massive number, nearly 300,000 km/s, which means that light can go around the earth 7.5 times in second. Let's put it this way, if you were a photon you would never be late for school. In other mediums light travels slower. Scientists use something called the "refraction index" to compare the speed of light in vacuum vs another medium n is the refraction index in a given medium c is the speed of light in vacuum v is the speed of light in that medium This table has some sample refraction indexes for transparent mediums. So, for example the in...

I bought myself an optics kit as a Christmas present. It is awesome because it has lots of lenses, mirrors and lasers. I have been learning lots with it and I will be posting a few blog posts about this topic. I don't to spoil it but I will show you how to build your own telescope. But for today I will teach you what I have learnt about the human eye. There are two things that control the amount of light that enters your eye:  the eye lids and the iris. I don't need to explain you what the eye lids are, because I think you already know. The other one is the iris which is the coloured part of your eye. One thing I learnt about it is that the pupil is just a hole in the iris, that gets bigger or smaller to let in the right amount of light. So it is not a thing by itself, it is just a hole in the iris. It is black because it is very dark inside. A curiosity of mine is that every human's iris is different, which is why it can be used for recognition. Then, there are two parts o...

To round up the blog series about the vacuum chamber I am going to do a very cool experiment. I will show you how to boil water at lower temperature than normal. I am sure you know that water freezes at 0 degrees Celsius and boils at 100 degrees, but this is only true at sea level. For example, if you climb Mt Everest and try to boil an egg, it will take you way longer because up there water boils at only 68 degrees. The cool thing is that with my vacuum chamber I can achieve even lower pressures than Mt Everest, which is like climbing even higher. This also means that I can bring the boiling point of water even lower. To understand why all this happens you need to understand a phase diagram. To see my explanation and the experiment make sure you watch the video. During this project I also got to learn about the critical point and supercritical fluids that occur at much higher pressures than it is safe for me to do at home. If you are interested to learn about that topic you can watch ...

Even though my vacuum chamber is quite basic, now that I have it there is no shortage of ideas to do with it. I once heard the saying that "nobody can hear you scream in space". So I decided to to see if it was true. First I learnt that sound consists of waves of air pressure. That explains why you can't hear sounds in space, because there is no air. Sound waves are longitudinal which means that air particles oscillate forwards and backwards much like a slinky. This is very different to other waves like light where they oscillate sideways like when you shake a string. I also learnt about amplitude and frequency. Amplitude is what defines the how loud the sound is. Whereas frequency determines the pitch, the higher the frequency the higher the pitch is. During my research I learnt about other things like the Doppler effect and how speakers work. A thing I particularly enjoyed was this video from Animagraffs which is one of my favourite channels in YouTube:  https://www.you...

Today I am telling you about a vacuum chamber I have built at home. This is going to help me perform many experiments. You will see more posts coming soon about this topic. I built it with a simple jar, a big syringe and aquarium equipment link tubing and valves. You can find more find details in the video below. I had to drill two holes in the lid one for the pipe and another for a sensor. I used the BME280 sensor to measure the pressure inside with the help of a Microbit. This is what the sensor looks like. To read the values I installed the Enviro:Bit extension in the Microbit. This is the code I used. As you can see, with the BME280 you can also measure temperature and humidity. In this project we also learnt the importance of sealing the jar well as the air molecules are incredibly small and they will try to get get in and ruin your vacuum. I used a hot glue gun to seal the gap in between and around the cables. This is what the finished setup looks like. In this video you will see...

During science week I saw a conference from an astrophysicist showing us photos of stars. He told us what a reflector telescope is and how it uses a parabolic mirror. So I asked my dad about parabolas and he told me about the conic sections. Conic sections are different shapes you get by cutting a cone at different angles. I decided to see this by myself using Tinkercad. You can find other posts in the blog talking about Tinkercad if you are interested. It is very easy to use. These are all the sections I created When you cut a cone horizontally you get a circle. Here we have represented the circle in yellow. If you cut a little bit more inclined than horizontal you get an ellipse. Here you can see three different ellipses at different angles in red colour and how the first one compares with the circle. The more you incline the cut, the stretchier it gets. Ellipses are cool because that's the type of orbit planets do around the Sun If you keep inclining the cut eventually you reach...

The idea for this experiment came from learning about forces in school. I wanted to make an experiment to share my new knowledge with my class. This experiment is about seeing how much a spring will stretch if a certain amount of weight pulls from it. This is called Hooke's law, after the scientist that first proofed this concept, Robert Hooke. Procedure I attached a spring under a table with a hook at the end, so that I could hang different weights. I also fixed a ruler to the leg of the table to do the measurements Then I created different weights by putting water in a bottle for specific amounts of weight. For reference 100 ml of water is 100 grams. Next I hung the bottle and measured the amount of stretching on the spring from its original position I made note of the measurements in my notebook and then put them on a graph I discovered that the points formed a line. That's very interesting! That made me think, can I use this graph to predict what will happen if I hang any w...