The relation between the movement of spiral waves and their tip for a simple spiral is experimentally investigated in a spatial open reactor using the Belousov-Zhabotinsky reaction. In the quasi-two dimensional regime, our results agree with the combustion model proposed by Lázár et al. [Chaos 5, 443 (1995)] which states that the speed of spiral tip movement is proportional to the speed of spiral waves, c(tip) infinity c(front), when expressed in the radius of the spiral tip trajectory R and the spiral wavelength lambda, R infinity lambda. The measurement shows that the slope of the linear R-lambda curve is about 0.13, independent of the control parameter. This observation is also consistent with the combustion model.