Have you ever pricked your finger and looked at the drop of blood that forms? In that one tiny drop of blood, there are thousands of living cells, and some of those cells are locked in a fight to the death!

Our bodies are made up of trillions of tiny living building blocks called cells. A cell is so tiny that you can only see one using a microscope. We have over 200 different kinds of cells in our bodies: hair cells, skin cells, blood cells, muscle cells – everything in your body is made up of different kinds of cells. And every single cell in your body will die without the oxygen we breathe in. So how does that oxygen get all the way from your lungs to the cells in the tip of your little toe? It’s carried by your blood!

Blood is actually made up of many different things, just like soup is made up of many ingredients. If you put a drop of blood under a microscope and take a look, most of what you’ll see are red blood cells. These cells are shaped a little bit like a doughnut, and their job is to carry oxygen through your body. They are bendable to fit through your smallest blood vessel, and almost half of your blood is red blood cells – that’s why your blood looks red.

Blood cells float in a liquid called plasma that helps to carry them around your body. If you take all the red blood cells out of it, plasma actually a pale yellow colour. It’s full of dissolved salts and other good things that help keep your cells healthy.

Any elementary science class will tell you to avoid cutting yourself because it lets your plasma and blood cells escape. Ouch! The good news is that your blood also contains tiny bits of cells called platelets. If you get a cut, platelets will stick to the edge of the cut and to each other. Eventually, so many platelets stick together that they form a plug, or clot, that stops any more blood from getting out. But sometimes, if the clot doesn’t form fast enough, some tiny invaders might find their way in.

Have you ever gotten sick and been told that you’ve caught a bug? What that means is that tiny living things called microbes have gotten into your body and are producing nasty chemicals that make you ill. Those same microbes can sneak into your body through a cut. Fortunately, you have some pretty tough defenders – your white blood cells!

White blood cells are the biggest cells in your blood, and their job is to seek out and destroy any invading microbes that get in. If a white blood cell senses the chemicals made by a microbe, they will swallow up that microbe and digest it! Sometimes kids science is just like a video game — in the arcade game Pac-Man, our hero is just like your white blood cells, travelling around your bloodstream and gobbling up the invading microbe ghosts.

So next time you prick your finger, remember that in that tiny drop of blood there are hundreds of living cells fighting against the nasty microbes that want to make you sick. Your tiny drop of blood is a battlefield, but luckily you’ve got the white blood cells on your side!

Post by Sarah

Everyone knows that the prettiest insects are bright colorful butterflies, and that their cousins the moths are dull and boring, right? Wrong! There are some butterflies with plain brown wings, and some moths whose wings sparkle with every color of the rainbow. So how do you tell the difference?

Fun Fact 1: Moths and butterflies have different antennae

Moths have two kinds of antennae: one kind is long and thin, and the other is shorter and bushy, as if the moth has two big feathers stuck to its head. Butterflies only have one kind of antennae: long and thin, but with a knob or a ball on the end.

Fun Fact 2: Pupa protection

Imagine that halfway through growing up, you have to rearrange your entire body, grow new limbs, and learn to fly. That’s what life is like for moths and butterflies. They start life as a larvae, or caterpillar, and spend most of that time eating leaves and growing big and fat. Then, when they’re ready to change, they become a pupa and their entire bodies shift around into their final form: a moth or a butterfly.

Moths and butterflies, like all insects, have an exoskeleton. This means that the hard part of their body that give them their shape isn’t on the inside, like our skeleton is. It’s on the outside. When butterflies go through their pupa stage, their exoskeleton forms into a solid shell called a chrysalis. This usually hangs underneath leaves, glued there by threads of silk that the caterpillar made just before it changed into its pupa stage.

Moth caterpillars make silk too, but they don’t just use it to glue themselves to leaves. Instead of forming a chrysalis, moths will spin an entire coccoon of silk around themselves and go through their pupa change inside its fluffy protection.

So butterflies make a hard chrysalis, and moths spin a fuzzy coccoon.

Fun Fact 3: To spread or not to spread

Still not sure if you’re looking at a moth or a butterfly? Then take a look at its wings when it comes to rest. Moths rest with their wings stretched out, but butterflies rest with their wings folded up.

Use these fun facts, and figuring out whether you have a moth or a butterfly should be as easy as 1-2-3!

Some more fun facts about moths and butterflies:

Moths and butterflies like salt, and there is one kind of moth from Madagascar with an extra-long mouth to let it drink the tears of sleeping birds at night!

Silk that we wear comes from the coccoons made by the caterpillars of silk moths. The coccoons are boiled to dissolve the glue that holds them together, and slowly unravelled into one long, thin thread!

Monarch butterflies are some of the best travellers in the world. Every year they travel from their summer grounds in North America to their winter homes in Mexico and back again. Some have even been found to have crossed the Atlantic ocean!

Post by Sarah