Hi Orla,
welcome to this course. There are lots of posts in the forum with suggestions, resources and ideas from other teachers, including other 2nd class teachers, so I hope you find this useful.
Gravity and falling things is fun to explore, if you find that when you drop ordinary things they fall too fast to compare you could try rolling them down a ramp – it will be a bit slower – although friction/rolling will then come into play.
This is how Galileo explored gravity back in the 1600s! See this teacher article on his thinking.