Why is it easy to swat a fly with a fly swatter, but not your hand?

leverage and length

To use a fly swatter you just have to flick your wrist quickly-so the swatter usually gets there before the fly sees it. When you swat with your hand, you have to swing from your shoulder and your arm is alot heavier. This makes it slower and the fly can see it before it gets there.

this is but a guess but I'd say it would have to do with air flow. As your hand approaches the fly it pushes the air and the fly aside. With the fly swatter the holes allow air to pass through and thus the fly isn't pushed aside.

I guess, it is psychological. The mere thought of having your hands laid on dirty things will cause you to miss the target.

With a swatter, you hit the fly free and easy.

It's all about 'clubhead speed', just like in golf. The fly swatter is simply moving faster.

A neat trick to get flies bare handed though is to clap your hand just above them. They will instintively fly up into your clapping hands.

oh! I know this one! It's because of the holes in the fy swatter. Flies can sense the air pressure of your hand or newspaper as it comes at them & have pre-hit warning.

Both theories are correct. The longer arm allows for a faster swat. The holes also reduce the pressure wave, so it does not alert the fly.

a fly swatter extends your hand so you dont get physically close to it so they think its just a branch or something.

Well, the flyswatters have long handles that extend from your hand, so its like you have a longer arm. And it might seem that if you hit your hand too fast you'd hurt yourself, so for some people when they think of that risk they go slower when trying to whack a fly with their hand, therefore missing it.

Best way to kill flies is by binding 3 or 4 rubber bands to each other and just aim with one end and let loose the other end like a catapult....flies don't stand a chance 9 out of ten they will be squashed and you'll get to enjoy it.

Flayswatters have the flexibility so the impact and the speed is quicker with the force from your hands when you use it. But when you use your hand the speed is not quick enough for the reaction of the fly.