Evan's Space

Wonders of Physics

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Data representation in tables (with 8 examples)

The digital stopwatch has a precision of 0.01s.

Depending on the experiment, the recording of measured time may be to the nearest 0.1 s or the nearest 1 s, even though a typical digital stopwatch has a resolution of 0.01 s. This is to account for uncertainty due to human reaction time or due to the time taken for observing whether an event has indeed occurred. More importantly, do follow the instructions given in paper. That will take precedence.

In general, the following should be considered when using a stopwatch to record time:
1) Human reaction time
Uncertainty due to the reaction time required between deciding that an event has
occurred and stopping the stopwatch, e.g., time taken for a pendulum bob to make 20
oscillations should be recorded to 1 d.p. in seconds.
2) Nature of experiment
Uncertainty due to the time taken for observing whether an event has indeed occurred
e.g., time at which water starts to boil or a chemical reaction takes place should be
recorded to the nearest second.


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The great pressure of the deep ocean

https://www.channelnewsasia.com/world/titanic-expedition-titan-sub-debris-no-survivors-oceangate-search-rescue-implosion-3580936?cid=internal_sharetool_androidphone_23062023_cna

The deeper the Titan goes under the water, the greater the pressure on the wall vessel of the Titan.

Liquid pressure P = ρgh

Liquid pressure = density of water x gravitational field strength x height of water before water surface

Inside the vessel, the pressure is maintained at about atmospheric pressure for the crews to breathe normally, just like on sea level or on ground.

Due to the huge pressure difference between outside and side, the Titan will implode when the hull of the vessel is not able to withstand the pressure.

Deepest condolences to the crews…

https://www.straitstimes.com/world/titan-submersible-what-is-a-catastrophic-implosion


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Physics Practical – Finding gradient and y-intercept

Once the best fit line is drawn, it is very common to find the gradient. Finding the gradient and showing on the graph how you get the gradient will usually be awarded 2 marks.

Besides the gradient working of (y2 – y1) / (x2 – x1) in the space provided with correct s.f and units is usually 1 mark

Choosing 2 new points on the line (far apart) to find gradient, with dotted triangle and coordinates of the 2 new points is usually 1 mark.

View the video below to find out more. There are 4 examples in the video to show you the different gradients and how to find the y-intercept.