Scratch

abs: absolute value.  Reports the positive version of the input.  (-1 -> 1, 1 -> 1).

sqrt:  square root.  Reports the number that, squared (times itself), would equal the input.  (sqrt 81 = 9, because 9 * 9 = 81).

sin, cos, tan, asin, acos, atan, and ln: These are trignometric functions (very complicated).

e^:  Reports the constant e raised to the input.  If you don't know what e is, you'll never need to use this block.  Like trigonometry, very complicated.   

10^:  Reports 10 raised to the input.
10^-2 = 0.01
10^-1 = 0.1
10^0 = 1
10^1 = 10
10^2 = 100

Greenatic explained the abs and sqrt functions well enough. Here's a description of the others.

Sin, cosine, and tan are trigonometric functions. Sin and Cosine go from -1 to 1. It's a ratio of the different sides of triangles. Arcsin, arccos, and arctan are the inverse functions of sin cos and tan and are used to get the angle back from a ratio. You can use these in Scratch in physics simulators to work out the different components of vector quantities, such as the motion of a cannonball.

To understand the ln function, you need to understand what e is first. e is a constant, and the graph of f(x)=e^x is very unique, because the gradient at any point of the graph is always equal to the value that of f(x). It's very useful for modelling exponential change in physics.

Ln is the natural logarithm, say you have ln(X)=5, it means that the constant e raised to the power of 5 is equal to X. Log is the same as ln except it can use any base, not just e. I think in Scratch you can only use log base 10. It means if you have log5=X, it means 10^X=5, so you can use it to work out the power that number must be raised to to achieve the final value.

10^ is called standard form, it's useful for displaying very large numbers in a small space. For example, 1,000,000 would be 1.0x10^6.

Hope this helps 

sin;
cos;
tan;
asin;
acos;
atan;
ln/in*;
log;
e^;
10^.

Last edited by marcsteene (2011-12-18 12:39:08)

I was just thinking the same thing! The posts above helped me though.