My 7 year old daughter has shown an increased interest in science and how things work, my 5 year old loves to investigate and opening things to see what is inside. After a colleague mentioned a new toy called GoldieBlox which encourages girls engineering concepts I had to buy it as a Christmas present. Keeping a girly feel to the toy and designed in a way girls think and look at things, it is intended to get girls more into thinking beyond dolls yet it includes a toy dog and other characters. I think they will both enjoy it and I will post images and review more once they have played with it.
I found these test tubes with experiments included that I think are great stocking stuffers for kids. My girls want to make snow so now they can and how your body can create energy which lights up the tube. Finally how sand can stay dry in water. I think these are all great products for girls who want to know how things work. All kids want to understand why things do what they do and girls more than ever should be encouraged to investigate.
Instead of the usual dolls, kitchens (which they have) I think it is also important to mix it up with toys that are fun but they learn at the same time.