How do I make my fireball explode?

Explode as in different spheres expanding outwards on contact with a surface. Not exploding like a grenade.

Player = game.Players.LocalPlayer
local Mouse = game.Players.LocalPlayer:GetMouse()
Ammo = 1

Mouse.KeyDown:Connect(function(key)
    key = key:lower()
    if key == "f" and Ammo>0 then
        local x = Instance.new("Part", workspace)
        x.Shape = "Ball"
        x.BrickColor = BrickColor.new("Deep orange")
        x.Transparency = 0.3
        x.TopSurface = "Smooth"
        x.BottomSurface = "Smooth"
        x.CanCollide = false
        x.Parent = workspace
        x.CFrame = Player.Character.HumanoidRootPart.CFrame*CFrame.new(0,0,-6)
        local v = Instance.new("BodyVelocity",x)
        v.MaxForce = Vector3.new(math.huge, math.huge, math.huge)
        v.Velocity = (x.Position - Mouse.hit.p).unit*-100

        Ammo = Ammo-1
        wait(2)
        Ammo = 1
        x:remove()

    end
end)