©  2017 Virtual Science Ltd

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Current scientific calculators only do half the job,  they calculate the numbers whilst leaving out the units. Keylink’s calculator does both and it does it in a very easy to use intuitive way. The calculation (shown on the right) for the force on a 10kg mass at the Earth’s surface is simply calculated by using the usual keystrokes with a few extra to specify the units. For example:


Clicking on G for the Gravitational constant in the bottom left panel followed by the usual multiplication key.


Selecting the mass of the Earth from the Constants/Astronomy menu followed by the usual multiplication key again (the units are automatically included).


Selecting the digits one and zero from the number pad and then the units (kg) from the units panel


Selecting the division operator from the Operators panel on the right.

Selecting an open bracket from the Operators panel.


Selecting the radius of the Earth from the Constants/Astronomy menu followed by a closing bracket.


Clicking on the up arrow to raise the denominator to a power and then clicking on the number 2.


Finally the equal sign is clicked on and the/answer is calculated and displayed with the correct units!

This is what makes this such a powerful tool for science. Any mistakes are made obvious by the units. This is a perfect tool to  keep on the taskbar instantly available for performing worked examples in front  of a class.

The constants menu takes lists of constant names and values from a set of editable files so new values can be added to making the  calculator suitable for any science subject.


There are menu items for  Astronomy, Chemistry, Biology and Physics as well as a separate ‘User’ entry for any constants that fall outside of these. This can completely eliminate the need to type in values when performing calculations which means an error free performance in front of the class.


Calculations can use up to four memory locations which can be used to feed different values into the equations. These values need units too! Equations can be saved and loaded to be used with new values. The same calculation using a memory location. This way results can be quickly obtained for a set of values without editing the original equation. Note the ‘kg’ unit in memory ‘M1’.

Here’s another example showing the calculation  of resistivity (a voltage of 1.44V, a wire of diameter 1.2mm and a length of  125mm, a current of 7.4A ). Notice the result has the units ‘ m‘. It uses in the result even though it is a derived unit because the calculator knows the base units for each derived unit and matches them against the units of the result using the one that shortens the answer the most hence giving the most useful result. This is how science calculations should be done and mirrors  the examples used in more enlightened texts in that they show worked examples with units for all number used.

Now also available for Android at just £2.49.


Click here for the  entry on Play Store where you can see a video.


Or see video below: