It was lunchtime on the farm in Brisbane. Little Thunder was eating his hay when Suzy came running.

"Let's call Tokyo the cow and say hello!" she said. Tokyo was visiting her cousins in Japan.

"Will she be having lunch too?" asked Little Thunder.

Spike looked at the big kitchen clock. "It's twelve o'clock here. Tokyo is one hour behind Brisbane. So it's eleven in the morning there."

"Behind?" asked Little Thunder. "Is Japan slower than us?"

"No," laughed Suzy. "The Earth spins, so the Sun rises at different times in different places. Each place sets its clocks to match its own sunshine. Those are called time zones."

They made the call. Tokyo waved from a busy street. "Good morning from Japan! I'm just having morning tea."

Next, Little Thunder wanted to call London the cow, who lived in England.

Spike counted on his paws. "London is ten hours behind Brisbane right now. So it's two o'clock in the morning there."

"She'll be asleep!" said Little Thunder. "Let's not wake her."

"What about Denver in America?" asked Suzy.

"Denver is sixteen hours behind," said Spike. "So it's eight o'clock at night there. But it's yesterday!"

Little Thunder's mouth fell open. "Yesterday? How can it be yesterday?"

"Because when it's lunchtime on Wednesday here, Denver hasn't reached Wednesday yet," explained Suzy. "They're still on Tuesday night."

"And some places move their clocks forward an hour in summer," added Spike. "That's called daylight saving. It changes the sums."

Little Thunder rubbed his head. "Time is confusing."

"Let's call London tomorrow," said Suzy. "At six o'clock in the evening for us. That will be morning for her."

"Good," said Little Thunder. "She can have breakfast while I have dinner."