Passing a variable to method and using the method return value in C#

I am trying to pass a variable to a method, i.e. velocity(decent), and call that method several times in a while-loop.

It seams to not be working and I don't know what is wrong with this.

I want the decent variable to increase up to 250.

I tested the velocity(decent) method outside of the while loop and it worked. Inside the while-loop it just stays 0, while the altitude is decreasing each time it goes though the while loop.

using System;using System.Collections.Generic;using System.Linq;using System.Text;// Every measuerments are in feet and seconds// This program is to sim a simple jump with no graphics. Work the numbers out for final implementaion.namespace Jumper1Test{    class Program    {        //10 - 20 feet above ground pull both cords to slow down to about 0 ft per second        private static int alt;           //in feet 30,000 20,000, 15,000 ft *Note keep decent same scale\measurment        private static float decent = 0;  //speed of jumper 250ft per second cute deploed 15-20ft p[er second want to hit 0 when landing        private static int cuteDelay = 3; //3 second cute delay after opeing (ruf estimate on average)        private static bool leftCord;        private static bool rightCord;        private static bool cuteDeployed; //if parachute is deployed        private static bool jumped;       //jump iniciated        //environtmnet effects        private enum windDrection { North, South, East, West, NE, NW, SE, SW } //NE NW = North East West respectivly        private static int windspeed;     //in knots        static void Main(string[] args)        {            Console.WriteLine("Jump Sim 1.0");            //select the hight for the jump            Console.WriteLine("Enter Jump Altitued:");            Console.WriteLine("a for 30000 Ft");            Console.WriteLine("b for 25000 Ft");            Console.WriteLine("c for 15000 Ft");            String alt1 = Console.ReadLine();            if (alt1.Equals("a"))            {                alt = 30000;            }            else if (alt1.Equals("b"))            {                alt = 25000;            }            else            {                alt = 15000;            }            Console.WriteLine("The Hight of the jump is " + alt);            //jumping            int countdown = 5;            while (countdown != 0)            {                Console.WriteLine("Jumping in " + countdown);                System.Threading.Thread.Sleep(1000); //wait for 1 secod.                countdown--;            }            Console.WriteLine("Jump!");            while (alt != 0)            {                alt = alt - 5000;                Console.WriteLine("Altitue = " + alt);                velocity(decent);                Console.WriteLine("Speed is: " + decent);            }            // keep screen from going away when run from VS.NET            Console.ReadLine();        }        private static float velocity(float decent)        {            for (int i = 0; i < 8; i++) //its takes 8 seconds to reach terminal velocity            {                decent = decent + 31.25f; //increease speed of fall                System.Threading.Thread.Sleep(1000); //wait for 1 secod.            }            return decent;        }//end of velocity    }}