Throwing things down the stairs - how to stop?

[Jimjams]

Any ideas- before this gets out of hand? Ds1 obviously. He's doing it out of interest. He's being encouraged to throw and kick balls at the moment -but as well as throwing stuf, he also climbs to the top of the stairs (and that bit of the house is 4 stories) and drops things. Some of which are big and heavy (like toy trucks etc). Am rather worried something's going to end up on ds2's head. He seems fascinated by the way things fall. And has favourites like the kiddy toilet seat (now out of reach).

The only way I've managed to stop unwanted behaviour like this in the past is to prevent it happening at all- but I can't shadow him all the time- and I can't remove everything he could possibly throw obviously. He's not very good at being told off after the event doesn't seem to "get it". Any ideas?

i was told water (bath,lots of containers, water wheel, watering the garden etc.)is a good one as it also calms them down. i've been trying to find the link but have just realised it was an article the teacher leant me published by the 'pen green centre'. my memory is hazy but they had examples of a boy who liked to take things apart, they explained he wasn't being naughty just trying to make sense of abstract concepts - he had previously taken his parents camera apart. so they brought a camera into school, took him to the camera shop bought some film, helped him to put the film in, and let him take some photographs, helped him to wind film up, take to shop and wait for them to be developed. at each stage they gave short explanations of things like light, how to point it at something and how the film becomes photographs. they did something similar for another child who was obsessed about doorbells - taking the fitting of the doorbell down, showing the batteries and wires, replacing batteries etc. another child loved string and they helped them make a string trail of their journey around the school which became a map. can't remember which schemas these related to but i have used them with my ds1. i will try and get hold of the article again as it had some other ideas for vertical shcemas and the old brain just ain't what it use to be...