为了鉴别甲物质是否为晶体，小琴根据实验目的，进行了认真规范的实验，获得的实验数据如下表所示。加热时间为1min时，甲物质为固态，加热时间为10min时，甲物质为液态，根据实验数据分析可知：甲物质（选填“是”或“不是”）晶体，做出此判断的理由是。                                                                                                                                                                                                                            

加热时间/min	0	1	2	3	4	5	6	7	8	9	10	11
甲物质的温度/℃	40	42	44	46	48	48	48	48	48	48	50	53