“That’s so funny I forgot to laugh,” I said.

“I’m not entirely sure that pigs have lips,” said Emily.

“Of course they have lips,” I insisted. “If they didn’t have lips, how could they whistle?”

“You know,” Ryan pointed out, “Mr. Klutz is just trying to trick us into doing lots of math problems. That’s why we’re having a chocolate party.”

“Who cares?” Michael said. “As long as we get the chocolate.”

“I think that only students who do math problems should be allowed to come to the chocolate party,” said Andrea.

“Could you possibly be any more boring?” I asked her.

As it turned out, everybody was doing math problems. The whole school started doing math problems like crazy. Even Ryan. You would have thought that Mr. Klutz was giving us gold and diamonds instead of chocolate.

“I did math problems for twenty minutes last night,” Ryan bragged while we were waiting for Miss Daisy after recess.

“Oh, yeah?” Michael said. “Well, I did math problems for forty minutes last night. Forty is twice as many as twenty. See? I just did another math problem right there!”

“Well I did math problems for an hour last night,” I said. “That’s fifty whole minutes.”

“An hour is sixty minutes, dumbhead,” Andrea told me.

I was going to tell her that Sixty Minutes was a TV show my parents watch, but Mr. Klutz suddenly burst into our classroom. He told us that Miss Daisy had a dentist appointment and we would have a substitute teacher for the rest of the afternoon…Mr. Klutz!

We all gasped.

“You’re not a teacher!” I told him.

“I used to be a teacher,” he said. “I taught for many years before I became a principal.”

“What did you teach?” Ryan asked.

“Physics,” he said.

“What’s that?” I asked.

“Is that like phys ed?” asked Michael.

“Mr. Klutz, do you know that this is second grade?” Andrea pointed out. “Physics is something high school students study.”

“Poppycock!” said Mr. Klutz. “You’re never too young to learn something new. You may find you’re smarter than you think.”

“Well, if you say so.”

“Physics is the study of motion and energy and force,” he said. “For example, if I take a blackboard eraser in one hand and a book in the other hand, and I drop them at the same time, which one will hit the floor first?”

“The eraser!” I said. “It’s smaller and lighter, so it will fall faster. Just like small, light kids run faster than big, heavy kids.”

“No, the book will hit the floor first!” insisted Ryan. “Bigger and heavier things build up more speed than little things.”

“I think they’ll both hit the floor at the same time,” said Andrea.

“Let’s do a test,” said Mr. Klutz.