China’s 1st large-scale sodium battery energy storage station put into operation
Category Archives: 23 Things Around Us
How to change a 2-pin plug to 3-pin plug?
In Singapore, we use the 3-pin wall socket 240 V. In general, it is more convenient if the plug of appliance is 3-pin. But certain appliances we bought online may not be, just like the fan shown in the video below. It has 2 pins, i.e. a live wire and a neutral wire. No earth wire is present as the outer casing is made of electrical insulator, plastic.
Take a look at the video, and you can easily convert the 2=pin to 3-pin plug.
What if wires in the 3-pin plug are swapped?
Possible for Singapore to have renewable geothermal energy from Sembawang hotspring?
Nail Polish Dryers Damage DNA and Cause Mutations in Cell Lines | Technology Networks
Balancing Toys
There are two main types of balancing toys.
Type 01: CG below the pivot point
Type 02: CG above the pivot
Worse than black? Japan study on heat-beating shirt colors reveals infrared absorbers – The Mainichi
How many girls are there?
Am I paying a lot on electrical bill for charging my phone?
With new advances in mobile devices, the battery capacity of the lithium-ion battery increases with each new model.
For instance, the flagships phone like iPhone 14 max Pro has an capacity of 4323 mAh, Samsung S22 Ultra 4855 mAh and the Z fold 4 4400 mAh. We tend to think that the constant charging of our phones will use a lot electrical energy, hence increases our electrical bill.
But is it true?
Polar bear understands the concept of preasure
Direction of friction on the wheel
There have been a few questions in Olevel asking students the direction of the friction on the wheel, It is important to consider if the wheel is connected to the engine or not.
Below is an illustration on this concept.
You can view the explanation plus the 4 examples from Olevel p1 in the video below.
Examples
Refer to the video above for the answers
Isn’t tyre with tread better in providing grip/traction/friction on the road in all weather?
Most of us know that when the treads of our typical car tyres are worn out, we need to change as to provide grip, hence our car will not skid easily.
But actually, the treads of our typical car serve a more important role during rainy days. They allow the water to be displaced (quickly letting the water to move into the treads) so that the tyres can still maintain contact with the road to provide the grip. Of course, if you still go too fast on a wet road, that layer of water may not be able to be displaced in time, hence grip on the road is greatly reduced and the car is likely to skid.
Especially in the recent F1 race in Singapore, due to the wet weather, the cars had to changed to hard wet tyres. Many may be puzzled why F1 cars uses smooth slick tyres during dry weather, contrary to our common sense for our typical cars. The graphic below hopes to provide some basic explanation to the wet and dry tyre and the function of the tread on tyre. Hope it helps.
The following video gives a good overview of how a tyre works. There is a lot of science behind them.
Why evaporative cooler does not work well in Singapore?
The world’s whitest paint can cool your house — and the Earth
https://www.freethink.com/environment/whitest-white-paint
White surface is a good reflector of radiation and light. This paint is even better!!
Tidal wave energy
Slinky coil guru!
Slinky coil can be used to show transverse or longitudinal wave. But do not quote slinky coil as an example of either wave.
But this guy is really pro with a slinky coil!!
Maybe I have been teaching wrongly…..
The skin of the orange has pockets of air. This makes the overall density of the orange lower than water, hence the whole orange can float. Without the skin, the ‘naked’ orange is denser than water hence it sinks.
But maybe we should include the feeling of the ‘naked’ orange 🙂 😀 hahaha
Testing for Gold
BMW Backed Impeller Thrusted Electric Wingsuit Can Fly at 185 MPH
Superwhite paint can cool buildings even in hot sunlight | New Scientist
Slinky Coil – Interesting Tricks and demonstrations of Transverse and Longitudinal Waves
Slink coil is usually used to demonstrate the two types of waves – transverse and longitudinal waves. But remember that when you are asked to state an example of each wave, do not quote slinky coil.
View the videos below to know more about the two types of waves.
Which direction is the Friction of the wheel?
Try these two questions. The phrase ‘the wheel is driven/connected to the engine’ is important actually. Hopefully you will know how to solve them!
Fiery Re-entry into Earth’s Atmosphere (updated)
This post was updated following the first astronauts launched by SpaceX returned home safely on 3 Aug 2020.
SpaceX’s Crew Dragon heat shield shown off after first orbital-velocity reentry
How do spacecraft re-enter the Earth? | HowStuffWorks
Why Is It So Difficult For A Returning Spacecraft To Re-Enter Our Atmosphere?
Returning from Space: Re-entry – PDF format
SpaceX In-Flight Abort Test
SpaceX Falcon Heavy- Elon Musk’s Engineering Masterpiece
Shuttle Atlantis STS-132 – Amazing Shuttle Launch Experience
How to Land the Space Shuttle… from Space
First astronauts launched by SpaceX return to earth (3 Aug 2020)
Double-Insulated Appliance – Air purifier in the classroom
Double-insulated appliances are common around us. The air purifiers in our classroom are one good example.
In these appliances, only two wires are needed, namely Live and Neutral wires. Earth wire is not required as the casing is made of insulator like plastic for this case.
The Uncle (aka Physics Guru) in coffeeshop
How did he do that?!
Another type of gadget to hang your bags by the table is this. As long as the centre of gravity (CG) is directly below the support area (area of the hanger in contact with the table), the bag will not fall.
Gravity Flying Jet Suit
Jet Suit Flight and Talk by Richard Browning
Setting Record
Real Ironman
Another kind of jet suit by another company
Convection Toy – Angels Carousel
This simple toy is made possible using convection current in the air.
The ‘fan’ of the carousel is similar to the windmill we are familiar with. Just that the kinetic energy of the wind is created by the stream of hot air rising up from the bottom. It is the opposite of an electric fan.
The Standing Broom Challenge
Fiery Re-entry into Earth’s Atmosphere
SpaceX’s Crew Dragon heat shield shown off after first orbital-velocity reentry
How do spacecraft re-enter the Earth? | HowStuffWorks
Why Is It So Difficult For A Returning Spacecraft To Re-Enter Our Atmosphere?
Returning from Space: Re-entry – PDF format
SpaceX In-Flight Abort Test
SpaceX Falcon Heavy- Elon Musk’s Engineering Masterpiece
Shuttle Atlantis STS-132 – Amazing Shuttle Launch Experience
How to Land the Space Shuttle… from Space
Boiling water at reduced pressure – Water boils at 75 oC
At sea level (where most of us are), the standard atmospheric pressure is about 101325 Pa. The boiling point of water is at 100 oC which we are familiar with.
But as you climbed up e.g. Mount Everest at 8,848 m, the pressure is low and the boiling point of the water is about 71oC. So that’s the hottest cofe you can have on top of the cold mountain!
Hence as the pressure decreases, the boiling point of the water decreases. As with lower pressure, the water molecules requires lesser energy to break the intermolecular forces to escape into the atmosphere, hence boiling point is lower.
This video shows the same effect. Using the syringe, the air is pumped out of the container to reduce the pressure. The water at 75Â oC , (below the usual boiling point of 100 oC) will start to boil and you can observe the bubbles forming!
Ring of Fire Solar Eclipse
View from Bishan-AMK Park, Singapore
Amazing wind walker beast
It’s amazing to watch these strandbeasts walk and solely powered by wind.
Wind energy to mechanical energy 🙂
This is a toy version of the wind walker.
Real-life ‘roly-poly toy’ – China
Maybe ships are unsinkable in future!
2017PurePhyP2Q5 Two points on the rope wave with displacement-time graphs given
In this this question, the displacement-time graphs are given, which are different from displacement-distance graphs.
In the displacement-time graphs of A and B, they show the displacement of that particular point at different timing. E,g, at t = 0s, the A is at the rest position (0 displacement) and at time 0.2 s it is at the maximum displacement. This means A is going up from t = 0 s to 0.2 s.
Solutions:
(a) Amplitude: 1.5 cm
(b)(i) Frequency is the number of complete waves produced in 1 second.
(ii) period T = 0.8s, f = 1/T = 1/0.8 = 1.25 Hz
(c) Closest possible positions of A and B, (refer to the video), is when the
time taken for the wave to move from A to B is T/4 = 0.8/4 = 0.2 s.
speed = distance/time = 38/0.2 = 190 cm/s approx. 200 cm/s
(ii) There are various possibilities in which B can be 38 cm to the right of A. Besides T/4, it can be 1.25T or 2.25 T etc. Hence the speed can be other values.
Refer to the video explanation below
Thick Cable for High Power Appliances
Double Insulation
Function of Earth Wire
What will cause the fuse to melt
Function of Fuse
The 3 pin plug
This Huge Electric Dump Truck Never Needs to Plug In | WIRED
Watch “Michelin and General Motors Unveil Airless, Puncture-proof Tires” on YouTube
Transparent Solar Panels Will Turn Windows Into Green Energy Collectors
Marshmallow Hulk in Vacuum Jar
When the pump is switched on and the air in the jar is gradually removed, the pressure in the jar decreases. There will be fewer air molecules per unit volume in the far. Hence rate of collision of the air molecules with one another and with the wall and hulk will be reduced. As pressure P = F/A, the force acting per unit area decreases, the pressure decreases.
In the marshmallow, there are pockets of air at normal atmospheric pressure initially. As the pressure in the jar decreases, the pockets of air in the marshmallow expands due to this pressure difference. Hence the hulk expands and its volume increases.
Jaw-dropping video shows Virgin Galactic pilots blasting into space – Science – Mashable SEA
A New “Solar Paint” Lets You Transform Your Entire House Into a Source of Clean Energy
The project to remove 88,000 tons of plastic from the Pacific has begun
Glad to see such projects which benefit the environment.
Evan's Space 