### Fermi Problem Friday

We are one week away from Halloween. Around the world, kids, parents and the undead (aka college students) are preparing their costumes for the big night of trick or treating. Tricks! Treats! That's the best of both worlds.

Now one has to be very careful when choosing a Halloween costume. Nothing would be more embarrassing than spending a week constructing a clever Hannah Montana costume only to find out that your best friend had the same idea! Who is going to dish out candy to two Hannah Montanas? You have to coordinate and play rock paper scissors to determine who has to be Lola.

However, there is one costume that breaks all of the rules. It's almost as if there is a law of physics that states: You can never have enough zombies on Halloween. Two Hannah Montana zombies could bring in up to 4 times as much candy. And this is the good kind of candy like Swedish Fish.

This brings us to the question that Fermi (might have) pondered every year: How many zombies will be roaming around on Halloween night?

Now, I know what you are thinking. A Hannah costume is too elaborate and expensive. Let me suggest some clever physics options:
Be a Physics Central Zombie. Print out the Physics Central homepage and duct tape it to an old shirt. Then squirt smear some ketchup on it.
Similarly, you could be a Fermi Problem or your favorite wave function.

Have Fun and be safe (don't be an LHC blackhole zombie -aaaahh!).

Photo credit: Mark Marek

1. Q: How many Zombies will be roaming around on Halloween night?
A: ALL OF THEM!

2. Halloween day is for fun and zombies all around.

### How 4,000 Physicists Gave a Vegas Casino its Worst Week Ever

What happens when several thousand distinguished physicists, researchers, and students descend on the nation’s gambling capital for a conference? The answer is "a bad week for the casino"—but you'd never guess why.

### Ask a Physicist: Phone Flash Sharpie Shock!

Lexie and Xavier, from Orlando, FL want to know:
"What's going on in this video? Our science teacher claims that the pain comes from a small electrical shock, but we believe that this is due to the absorption of light. Please help us resolve this dispute!"

### The Science of Ice Cream: Part One

Even though it's been a warm couple of months already, it's officially summer. A delicious, science-filled way to beat the heat? Making homemade ice cream.

(We've since updated this article to include the science behind vegan ice cream. To learn more about ice cream science, check out The Science of Ice Cream, Redux)

Over at Physics@Home there's an easy recipe for homemade ice cream. But what kind of milk should you use to make ice cream? And do you really need to chill the ice cream base before making it? Why do ice cream recipes always call for salt on ice?