Why would you ask for a 30-gallon air compressor and a pressure washer for Christmas? To build your own backyard snowmaking machine, just like 10-year-old Forest Pearson of West Linn Oregon did.

Good gravy this looks like a lot of fun. (From katu.com)

People like you and I need a few things to live — we need healthy food, we need water, and we need air. Plants, though, are a little different than you and me. They need food and water, but they also need sunlight to live. Plants use sunlight as a way to make energy to grow.

Plants and animals, including people like you and me, breathe in air. But plants use a different part of the air than you or I do. We breathe in a part of the air called oxygen. We use the oxygen that we breathe in the air to feed the blood in our bodies. Plants use a different part of the air, a gas called carbon dioxide. We breathe in oxygen and breathe out carbon dioxide. Plants do just the opposite — plants breathe in carbon dioxide and breathe out oxygen. So the oxgyen you’re breathing now probably came from a plant. Thanks, plants!

Plants also get food from the soil. To live, they need a certain chemical that you can find in the soil. This chemical is called nitrogen. You have nitrogen in your body, too, but your body can’t use it. So when you get nitrogen in your body, your body gets rid of it. How does it do this? It leaves your body through pee and poo. All the stuff in pee and poo is stuff that your body can’t use. That’s why pee and poo is sometimes called “waste” — because it’s something leftover that you can’t use.

But because pee and poo are full of nitrogen, plants love it! If you’re a tree and a dog pees on you, are you happy or sad? You’re happy, because that pee is full of nitrogen that you can use to eat. The same is true with poo. In fact, farmers take poo from their cows and spread it across their fields to make the plants in their fields grow better. This is called “fertilization” — the farmer is using cow poo to make it easier for plants to grow in the field.

This morning we made eggs for breakfast. We cracked them open and wondered, where did the chicks go?

The eggs you buy in the supermarket are unfertilized. That means a rooster has not fertilized the chicken’s eggs. Without fertilization, an egg will not produce a chick. What you see inside an egg are the yolk (the yellow part) and albumen (the egg white). The yolk and egg whiteprovide nutrition for the chick when it is developing. This is different from the way human babies get nutrition when they’re developing in the womb. Human babies get their nutrition from an umbilical cord attached to their bellies.

That’s how you got your belly button!

Today we were wondering about feelings. It’s fun to have good feelings, like the excitement you feel when you realize the end of the school year is a few weeks away. But sometimes we have bad feelings, too.

We talked about grief, the feeling you get when you lose something, or when someone close to you goes away. Why do we have feelings like grief? Wouldn’t it be better if we never felt bad? After talking about it for a while, we decided that grief has a purpose — it reminds us to value and love our family and friends while they’re with us.

Throughout history, people have wondered about their feelings. Poets and philosophers try to make sense of how we feel. But there are also scientists who investigate the way people feel. These scientists are called psychologists. Some psychologists are like doctors for your feelings; they try to help people who feel bad. Other psychologists do research to figure out why people feel different ways in the first place.

Principal Investigator: Celeste

Research Assistant: Jeffrey

Date: April 21, 2007

This weekend we decided to do another experiment with a science kit. This time we used a Snap Circuits Jr. electricity set to create a motorized fan. To our surprise, when we flipped the switch, the fan propeller ran for a moment, then suddenly launched itself into the air and flew across the room.

This experiment has three separate areas of science and math: The electrical circuit (to make the fan go), the part that makes the fan take off (called aerodynamics), and the grid that we use to build the electrical circuit (which a mathematician would call a Cartesian coordinate system, but we just refer to as “the grid”).

The Snap Circuits Jr. kit is an excellent way for kids to learn about electricity. It makes it easy to create electrical circuits without having to do any wiring. The set comes with a plastic grid with pegs on it that lets you easily snap various parts into place. These parts include motors, switches, lamps, noisemakers, and connectors (which take the place of wires).

To build the electric fan, we followed the instructions in the kit. We started by laying out the pieces we needed, including the propellor, the fan motor, an on/off switch, and about six connectors.

One of the things we learned when putting together contraptions with the Snap Circuits Jr. set is that you need to build a circuit — a complete circle of connectors going into and out of the batteries — to power something using electricity. The instructions make it pretty easy to put a circuit together by mounting the various pieces on the grid, but we found it a little hard to read the numbers and letters on the grid’s coordinate system. So we made them a little darker by drawing over them with a Sharpie marker.

Once we could read the coordinates on the grid, it was simple to put the components in place. We started with the batteries and the switch.

After that we snapped the fan motor into place. Nothing’s happening with our contraption yet because there’s no circuit — there’s no way for the electricity to travel through the fan motor to give it power.

Here we have all the components in place and we’re completing the circuit with connectors.

Finally we have our circuit, so all we need to do now is place the fan on top of the motor and throw the switch.

Here’s a picture of the fan running. The fan only ran for a few seconds before it vibrated loose from the motor and flew across the room. We know that fans that spin around fast enough are pushing air downward, which makes the fan want to move in the opposite direction. In this case, the air goes down, so the fan wants to go up.

We didn’t expect to see the fan fly into the air, though. This is the kind of result that scientists refer to as “exciting and unexpected”. When scientific investigators announce exciting and unexpected results, they are usually either ridiculed, given large research grants, or both.

The fan launching itself across the room was so exciting that we decided to make a video of it for your enjoyment.

Like most mammals, people have hair over most of their bodies. We aren’t covered with fur all over our bodies like animals are, and scientists think that people today have less hair than primitive humans did. Because of the way that creatures change over time, humans born today have less hair than they did thousands of years ago. But scientists don’t really know why this is — having less hair probably didn’t make it easier for ancient humans to survive.

It’s possible that people decided long ago that humans with certain kinds of hair were just more beautiful, and so those kinds of humans had more babies that looked like them.

Although you have hair on most of your body, some of it is too fine to see. Two places where you don’t have any hair are the palms of your hands and the soles of your feet.

Do you notice that adult men usually have more hair on their bodies than women? Adult men grow hair on their faces and on their upper bodies, while women do not. It’s possible to remove hair from your body by shaving it off.

Children don’t have much hair on their bodies (except for the hair on your head, of course). But as you grow older, your body will gradually change and you’ll grow more hair on different parts of your body. By the time you finish high school, your body hair will look more like what you see on an adult’s body.

We’ve begun sharing some of our experimental findings with the Wired Magazine GeekDad blog. We posted our heat transfer experiment there today and we’ll include some of our other posts on GeekDad in the future. Big thanks to Wired for helping us share the science.

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.