How can I stop my girl from going crazy whenever she sees a ball out?

Hello, I have a year old border collie. She is great in the house and also on the majority of walks. The thing is whenever she sees a ball out on the walk she goes crazy!. She howls, whines, growls, jumps at me, chews her lead to try and get off and howls at the person with the ball! This is starting to scare some of the children who have the balls. At the moment whenever I see someone with a ball I put her back on the lead before she runs over and takes the ball, which she has done once when a group of boys were playing football.
Molly has balls at home but is not that intrested in them, it's just when we are out. Any advice would be great thank you.

There are 2 border collies who do that in my local dog park.Theres a football pitch there and the dogs wait til a ball gets kicked over the fence then they go for it- it annoys the kids. I guess keep your dog on alead where there are kids/balls around- maybe take a ball with you when you go out ?

My BC is the same.
She won't run off as i have always taught her to watch me. I trained her with her tennis ball. If she listens to me then she has her tennis ball.
You need to get her more focused on you.

That reply is "spot-on",,,,,We were taught at training class that when u have your dog out in public/esp off lead, say on the beach- you have to become the most EXCITING thing on the beach to your dog either with the most fav toy/ball, or with food rewards and practise a LOT of re-call. Ive trained my JR to come to me with a whistle.Yes train your dog to focus on you.....funny most border collies we have come across are intensely focused on their owners/ball

Hi Becs I agree with the others, teach your girl to 'look at me ' (teach this with the help of a small treats held up in front of your face /when you say look at me and she does give a treat/praise) ..Having taught your girl to focus on you when you go out take tip bits or a ball with you and produce them when needed to get her attention

Thank you for all your advice, I have started teach her the 'look at me' command this evening. It's going well, I will keep it going until she has perfected it! I will take extra treats and her ball on her walk tomorrow morning. I will let you know how we get on!

Great ! It should go well- BCollies are so darned smart