Are humans animals? We don’t usually think of ourselves as being similar to dogs, cats or frogs, but to scientists, in many ways we are.

Scientists mostly divide the world of living things into animals and plants. If something gets its energy from sunlight and doesn’t move around on its own, a scientist will usually call that creature a plant. Grass, moss, pumpkins and apple trees are all examples of plants.

If a creature gets its energy from eating other things and it can move around on its own, then scientists call it an animal. Dogs, cats, frogs, fish, dinosaurs, and humans are all examples of animals.

Scientists have names for different kinds of animals depending on which kind of food they like to eat. An animal that eats mostly plants is called an herbivore. Horses and sheep are herbivores. Animals that eat mostly meat are called carnivores. Lions and tigers are carnivores. People are omnivores — we can eat both meat and plants (although some people choose not to). Dogs and pigs, as well as some birds and some fish, are also omnivores.

You might have heard stories about cavemen or seen them on television. Some people use the word “caveman” to describe primitive men and women who lived on Earth long ago, used weapons like spears and clubs, and found food by hunting and gathering.

There were primitive people who lived in caves thousands of years ago. But scientists don’t usually use the word “caveman” to describe ancient people. They use more precise terms depending on what kind of early humans they’re talking about. Primitive humans started appearing on Earth long ago — two hundred thousand years ago — and we call these humans homo sapiens. You and I are homo sapiens, too. There are older kinds of human ancestors like the Neanderthals, a kind of early human that lived in Europe thousands of years before homo sapiens appeared.

Neanderthals have since died out. As with dinosaurs, scientists know about them because of fossils: bones and other objects that we dig out of the ground. Scientists who study old things buried in the ground are called paleontologists.

In cartoons and stories you sometimes see cavemen and dinosaurs together. But scientists know that people and dinosaurs never lived on Earth at the same time. The dinosaurs died out long before humans appeared on Earth.

Principal Investigator: Celeste
Research Assistant: Jeffrey
Date: March 18, 2007

Over the weekend we picked up a Ein-O Science Kit at a local game store. On Sunday we did one of the experiments in the box. The Ein-O kits are pretty neat; they have instructions on how to do the experiment along with most of the materials you need.

Our Ein-O kit has four experiments, all having to do with heat. Our experiment demonstrated how different kinds of materials conduct heat. A conductor is a material that energy can pass through. So our experiment tried to show how heat travels through different kinds of materials.

In the experiment, we got a ceramic bowl from our kitchen and attached four types of material to the inside of the bowl. The kinds of material were: a wooden pencil, a plastic tube, a plastic ruler, and a metal spoon. All of the materials except for the metal spoon were included in the Ein-O kit.

To stick the materials to the inside of the bowl, we used bits of modeling clay, which was also included in the kit.

The kit also included some plastic marker discs that we stuck onto the materials with some butter. The idea is that the warm water in the bowl would travel up the materials and melt the butter, causing the plastic markers to slide off the materials. The materials that were better heat conductors would melt the butter more quickly.

After the materials were stuck to the inside of the bowl, we filled the bowl with warm water. It took us a few trials to figure out how much water to use and how warm we needed to get it. In our first trial, we heated 500 milliliters of water for 120 seconds, which made the water pretty hot. This turned the modeling clay to sticky goo after we poured it into the bowl. We noticed that if the modeling clay got too hot, it was too soft to hold the spoon onto the side of the bowl and the spoon would fall over. In our final successful trial, we used 400 milliliters of tap water warmed in the microwave for about 75 seconds.

We also had to make sure not to let the warm water touch the modeling clay. We did this by moving the modeling clay up to the rim of the bowl in our third trial. There was one last problem, though. In the third trial, we placed the markers too high, and the heat wasn’t strong enough to travel up the materials to melt the butter and move the markers.

During all the trials Celeste wrote down the time that we started and finished. During the third trial we waited about twenty minutes for something to happen, but because the markers were so high, nothing ever happened. During the third trial Celeste spent much of her time drawing pictures of princesses in her research notebook.

Finally, in the fourth trial, we moved the markers down so they were closer to the water. This time we were able to figure out from our experiment that the metal spoon conducted heat much more quickly than the wood or plastic. The marker slid off the spoon about three minutes after we poured the warm water into the bowl.

We don’t know exactly how long it took the butter to melt, because at the time the marker slid off the spoon, we were downstairs helping Mom unload groceries from the car. But we know that the spoon conducted heat the best because when we got back upstairs, none of the other markers had moved.

We’ve posted more photos of this experiment over on Flickr.

Your body, your house, your dog, the Earth: all these things are made of matter. Matter is the name that scientists give to all of the substances in the universe.

Is water a kind of matter? Yes, water is a kind of matter called a liquid. Other kinds of liquid include milk and the gasoline we pump into our cars. Water is by far the most common form of liquid on Earth, though — most of the Earth’s surface is covered by water.

Wave your hand through the air. You can feel the air wooshing past your hand. Is the air made of matter? Yes, air is a kind of matter called a gas.  Other kinds of gasses include carbon dioxide (which plants breathe) and helium (which is used to make toy balloons float).

Most of the things you can see or touch are made of matter. Even things you can’t see (like the air) are made of matter. Are there things in this world that aren’t made of matter? Yes: some things are made of energy, which is different than matter. There are lots of ways to see energy in the world. Sunlight is a kind of energy. When a bolt of lightning hits the Earth during a storm, that’s energy too.

People and most animals have tongues. Your tongue is good for three things:

• Helping you eat food
• Helping you taste food
• Making funny faces

We taste food with our tongues to see if the food is good to eat or not.

Did you ever notice that your tongue is bumpy? The bumps you feel on your tongue are called taste buds. They’re the part of the tongue that lets you taste things.

You have about ten thousand taste buds on your tongue. There are different kinds of taste buds for different kinds of tastes: sweet, salty, savory, bitter and sour.

When you take in a breath, what happens? If you take a big breath, you can feel air going into your body through your mouth. But why do we breathe? We breathe because our bodies need something in the air called oxygen. Oxygen is like food for our blood. You can’t see oxygen, but it’s there in the air, and people and animals need it to live.

Your body changes oxygen into a different gas called carbon dioxide. Carbon dioxide is what comes out of your body when you breathe out. You breathe in oxygen, and you breathe out carbon dioxide.

Trees and plants don’t breathe oxygen as we do. They take in carbon dioxide and they put out oxygen — just the opposite of people and animals. So having lots of plants around is good for people and animals — plants and trees make the oxygen that we need to breathe.

You may be learning to write letters and numbers in school. But how did ancient people figure out writing, in the days before we had schools?

People didn’t always write. Cavemen didn’t write. People started writing about six thousand years ago. To keep track of information, people would make little marks in soft clay using a tool called a stylus. Over time, people began to agree on what the marks should mean.

Different people write things in different ways. In this picture you can see the Rosetta Stone, which is carved with ancient writings. The Rosetta Stone is important because it shows three different kinds of ancient writing. Scientists were able to figure out a lot about what the ancient writing meant by comparing the letters on the stone to information they knew about these ancient languages.

The Rosetta Stone was created more than 2,200 years ago and was discovered in the year 1799 in Egypt. It is currently stored at the British Museum in London.