bentzion-
Hi.
This is a great topic that you can have lots of fun with.
There is a huge range of halachos that has science at it core. Just a few examples:
– The reason for the amount of time which one is required to wait between eating meat and milk.
– Why using electricity is forbidden on Shabbos.
– The halachic validity of hearing brachos or shofar either transmitted or amplified by electronic means.
– How one’s latitude affects the length of bain hashmoshos and the zmanei tefila.
– Why altering the size of a gas stove’s flame isn’t the same as raising or lowering the temperature of an electric stove on Yom Tov.
– Organ donation (controversial).
– Brain death and what’s considered death lehalacha (controversial, related to the above topic).
– Why the vesain tal u’mutar begins at a different date than it did in the nineteenth century.
– Chazaka in halocha vs. actuarial odds in different situations.
– (many more issues – the above is just an off-the-cuff sampling)