The Secret World of Alex Mack (1994)

After getting splashed with an experimental chemical, junior high student Alexandra Mack finds that she has uncanny new powers such as the ability to shoot electricity from her fingertips and morph into a blob of goo. Unfortunately, Alex has to keep her powers a secret, because the company that manufactured that chemical would love to find out who got doused with it. It doesn't help that Alex tends to glow when she gets nervous, but her best friend Ray and super-smart sister, Annie, are there to help out.