This app is used to demonstrate how a spherical object with a finite volume immersed in a fluid experiences an upthrust due to the differences in pressure around it.
Given that the centre of mass remains in the same position within the fluid, as the radius increases, the pressure due to the fluid above the object decreases while the pressure below increases. This is because hydrostatic pressure at a point is proportional to the height of the fluid above it.
It can also be used to show that when the volume becomes infinitesimal, the pressure acting in all directions is equal.
The following codes can be used to embed this into SLS.
I was looking for an extension to the Micro:bit Go set that I bought a while back and came across a robot set that is currently on sale. This set comes with most of the sensors a typical line following or obstacle avoiding robot needs. Currently, it is being sold at a fraction of the price of other similar Micro:bit robots, and is far cheaper than sets such as the Lego EV3.
After unpacking it earlier this evening after work, I managed to put together the parts by following the instructions, which were quite clear.
To program the robot using Micro:bit's Makecode, which is a block programming interface that is very similar to Scratch, you will need to download the Yahboom blocks by selecting Extensions from the Advanced menu.
Enter the following URL into the search bar: https://github.com/lzty634158/yahboom_mbit_en
You will then see the library of new blocks including those meant for the robot below:
A few simple lines of code are all that is needed for the light sensors to keep tracking a black line by turning whenever one of the sensors detect white while the other detects black.
After programming the robot, download the hex file into the Microbit and the robot is good to go.
My colleagues and I took the opportunity to visit the exhibitions during lunch time today. I learnt about 3M's solar films and retroreflection material, I^2R's speech-to-text recognition app with code switching capabilities (i.e. the app is able to transcribe English-Chinese mixed sentences) and cell-based prawn meat from https://shiokmeats.com/, among other things.
There was also an informative booth on Project Wolbachia (where male aedes mosquitoes infected with Wolbachia bacteria are released into the wild to control the population). I learnt that they could separate the male from the females at the pupal stage because male pupals are larger and got to stick my hand in a box full of male Wolbachia-Aedes mosquitoes.
This is a free public lecture by Dr Nergis Mavalvala (an astrophysicist from MIT) on how her team detected gravitational waves generated from colliding black holes and neutron stars at the Laser Interferometer Gravitational-wave Observatory (LIGO). Held on this coming Friday 26 Jul 2019 from 5 to 6 pm, the venue is at the Singapore University of Technology and Design (SUTD)'s Auditorium, along 8 Somapah Road, Singapore 487372.
I created a series of GeoGebra apps for the JC topics of Waves and Superposition, mainly on the concept of Phase Difference. The sizes of these GeoGebra apps are optimised for embedding into SLS. When I have time, I will create detailed instructions on how to create such apps. Meanwhile, feel free to use them.
Instructions on how to embed the apps into SLS can be found at this staging environment of the SLS user guide.
Phase difference between two particles on a progressive wave. Move the particles along the wave to see the value.
Phase difference between two particles on a stationary wave. Move the particles along the wave to observe how their velocities are different or similar.
Observe velocity vectors of multiple particles on a progressive wave.