Our family trekked to the school parking lot to watch the Annular Eclipse last night.  The kids ran and played, checking in every few minutes to peer through their solar viewers as the sun went from full circle to crescent-shaped.  It was a blast!

Here’s what we saw in our shoebox viewers before the sun disappeared behind the trees.

Some teenagers showed up at the parking lot with a telescope and projected the sun on a piece of cardboard.  It was really cool, and the image was big enough that you could see a sunspot!

Hold on to your shoe box viewers! On June 5th, Venus will pass between Earth and the sun.  I’ll find out more about it and let you know how to watch it!

The word lever comes from the french verb “lever” which means “to raise.”  A lever amplifies force, so you can lift something heavier with a lever than you would be able to lift without a lever. Scientists think the ancient Egyptians used levers to lift huge stones.  

Levers are simple machines that require only a beam (a long piece of wood, metal or steel) and a fulcrum, the support on which a lever pivots.  It’s easy to make your own lever  using a can, a rag, a yardstick and some sticks of butter. We cut our sticks of butter in half, but you don’t have to.

The can is your fulcrum and you can keep it from rolling by placing it on a folded rag. Balance your yardstick (your beam) on the can. It’s nice  to do this experiment with a yardstick, since you can use the markings to find the halfway point.

Place a stick of butter on either side of the ruler, halfway between the fulcrum (the can) and the end of the ruler.  Is it balanced?

Here’s the neat part.  Slide one of the sticks of butter all the way to the end of the ruler.  What happens? Put a second stick of butter on the stick of butter that you left in its original position. Now is it balanced?  You can move it a little if it’s not perfect, since it’s hard to get the can exactly in the center.

See how one stick of butter further from the fulcrum (the can) can easily hold the weight of two sticks of butter that are positioned closer to the can?  This demonstrates how a lever can help you lift something heavy.

What happens if you move the two sticks of butter even closer to the fulcrum? Can you add more butter and make it balance?

The mathematical expression for how a lever works is M=f times d. M is the turning force, or torque, f is the force you apply and d is the perpendicular distance between the force and the fulcrum. Basically, this “law of the lever” tells you exactly what you see: that the further you are from the fulcrom, the more weight you can lift using a lever.  (So one stick of butter at the end of a ruler can lift two or more sticks of butter on the other side of the fulcrum, depending on how far they are from the fulcrum.) You can also see why a longer lever might work better than a short lever.

The famous Greek mathematician Archimedes was also a physicist, engineer, inventor and astronomer, and he is credited with first explaining how levers work.  Later, in the renaissance, levers were classified as one of six simple machines, which can be combined with other simple machines and devices to form more complicated machines, like a bicycles. What levers can you think of on a bike?

I don’t have Archimedes to help me out with physics, but I’m lucky enough to have a dad who is physicist and came up with the idea for this project.  Not only is he my scientific consultant, but he’s the one who got me interested in science in the first place.

It’s getting nice outside. Time to start thinking about backyard science! Here’s one of our favorites, if you haven’t already tried it! W

“Kids aren’t getting dirty these days. They’re not playing in the mud, not playing in rain puddles,” says Dr. Truglio, of Sesame Workshop in a Wall Street Journal article, about getting your kids outside.

Next to the kitchen table, my back yard (or front yard) is my favorite science laboratory.  It has the added bonus of being easy to clean up.  For this fun, messy experiment, a hose and a few paper towels do the trick. Make your kids clean up whatever mess they make!

My dad, who is a physicist, told me about this great demonstration. It teaches kids a little bit about motion and force while letting them do something that they are rarely, if ever, allowed to do- throw eggs!  All you need is a sheet, some clothespins or string, raw eggs, and some paper.  (You could use newspaper or easel paper.  It is just to make cleaning up easier.)  I also used a portable table turned on its side as a wall, but you could just use a wall or the side of a garage and have your child hose it off when you are finished.

Hang the sheet up from a tree, if you have one.  If you don’t have a tree, you could hang it from anything else, or have two tall children or adults hold it.  Then have two kids hold the bottom of the sheet up, or tie it to chairs  so it makes a J shape when you view it from the side.  The idea is to keep the eggs from hitting the ground and breaking.

An object in motion wants to remain in motion. To stop an egg moving through the air, you have to apply force to the egg. In this case, the force will be applied by a hanging sheet, or a wall.

Throw a raw egg at the sheet as hard as you can. It won’t break because the sheet slows the movement of the egg as it comes to a stop.  The law of motion says that the faster you change the speed of an object, the greater the force applied to the object will be.  When you change the speed of the egg slowly, like the sheet does, it lessens the force applied to the egg and the egg remains intact.

Now, put some paper on a wall (or table like we did.) Throw an egg at the wall. You’ll see what happens when something stops fast.  Once again, the law of motion rules.  When you change the speed of the egg quickly, it stops with a lot of force.  SPLAT. This is my kids’ favorite part.

This is why they put airbags in cars.  If a car is moving and hits something, causing it to stop very quickly, the airbag act like the sheet, slowing the person in the car down SLOWLY and greatly reducing the amount of force they might hit the dashboard with.

Record your results in your science notebook, if you want to. Finally, be sure to wash your hands when you’re finished experimenting and cleaning up.  Raw eggs can have  bacteria called Salmonella living in them and on them. Have fun!

Would you be surprised if I told you that you could stand on a carton of raw eggs barefoot without breaking them? Or that you can squeeze an egg with all your might without even cracking it (provided there are no cracks in the egg and you’re not wearing a ring?)Here’s a video of us doing these eggsperiments on Kare 11 Sunrise news!

Chicken eggs have delicate enough shells that chicks can peck their way out, but their architecture  is nothing short of amazing.  Their arched shape makes them able to handle large amounts of pressure without cracking, which is extremely important, since hens must sit on them in order to hatch them out. Humans use arches too, for designing strong building and bridges.

Remove any rings you’re wearing, place a raw egg in a plastic baggie and wrap your hand around it evenly.  Squeeze as hard as you can. Did you break it?

If you’re feeling brave, open a carton of raw eggs, remove any that are cracked and make sure they’re all pointing in the same direction (pointy side up or round side up) and set them on the floor.

Remove your socks and hold on to a chair or someone’s hand.  Carefully step onto the eggs with your entire foot. Remember: pressure is force per unit of area. The idea is to equally distribute your weight, and therefore the pressure, across all twelve eggs.  Let go of the chair.

Did it work?  How important do you think it is to keep your foot flat?  What would happen if you tried the same experiment in pointy high-heels?

Remember to wash your hands after touching raw eggs so you don’t spread Salmonella bacteria around!

Diffusion is the name for the way molecules move from areas of high concentration, where there are lots of other similar molecules, to areas of low concentration, where there are fewer similar molecules. When the molecules are evenly spread throughout the space, it is called equilibrium. Imagine half a box filled with yellow balls and the other half filled with blue ones.  If you set the box on something that vibrates, the balls will start to move around randomly, until the blue and yellow balls are evenly mixed up.

Think about the way pollutants move from one place to another through air, water and even soil. Or consider how bacteria are able to take up the substances they need to thrive. Your body has to transfer oxygen, carbon dioxide and water by processes involving diffusion as well.

Lots of things can affect how fast molecules diffuse, including temperature.  When molecules are heated up, they vibrate faster and move around faster, which helps them achieve equilibrium more quickly than they would if it were cold.

Diffusion takes place in gases (like air), liquids (like food coloring moving through water,) and even solids (semiconductors for computers are made by diffusing elements into one another.)

You can watch food coloring diffuse through a colloid (gelatin) at home and measure how long it takes. Gelatin is a good substance to use for diffusion experiments since it doesn’t support convection, which is another kind of movement in fluids. You’ll need clear gelatin (from the grocery store or Target), food coloring and water.

Add 4 packs of plain, unflavored gelatin (1 oz or 28 gm) to 4 cups of boiling water. Pour the liquid gelatin into petri dishes, cups, or tupperware and let it harden.  Then, using a straw, poke a hole or two in the gelatin, removing the plug so that you have a hole in the jello about 1/2 inch deep.  Add a drop of food coloring in the hole in the jello.

Every so often, measure the circle of food coloring as it diffuses into the jello around it.  How many cm per hour is it diffusing?  If you put one plate in the refrigerator and an identical one at room temperature, do they diffuse at the same rate?  Why do you think you see more than one color for certain shades of food coloring? What else could you try?

Here’s a post on how to use this experiment to make sticky window decorations: https://kitchenpantryscientist.com/?p=4489

We made plates and did the same experiment using 2 cups of red cabbage juice, 2 cups of water and 4 packs of gelatin to see how fast a few drops of vinegar or baking soda solution would diffuse (a pigment in red cabbage turns pink when exposed to acid, and blue/green when exposed to a base!)

You can see the pink circle from the vinegar and the green one from the baking soda solution.

It’s also fun to experiment with the diffusion of substances across a membrane, like a paper towel.  This is called osmosis. Membranes like the ones around your cells are selectively permeable and let water and oxygen in and out, but keep other, larger molecules from freely entering and exiting your cells.

For this experiment, you’ll need a jar (or two), paper towels, rubber bands and food coloring.  Fill a jar with water and secure a paper towel in the jar’s mouth (with a rubber band) so that it hangs down into the water, making a water-filled chamber that you can add food coloring to.  Put a few drops of food coloring into the chamber and see what happens.

top “chambers” for food coloring

Are the food coloring molecules small enough to pass through the paper towel “membrane?”  What happens if you put something bigger, like popcorn kernels in the chamber? Can they pass through the small pores in the paper towel?

Do the same experiment in side-by-side jars, but fill one with ice water and the other with hot  water.  Does this affect the rate of osmosis or how fast the food coloring molecules diffuse throughout the water?

Think about helium balloons.  If you take identical balloons and fill one with helium and the other with air, the helium balloon will shrink much faster as the smaller helium atoms diffuse out more quickly than the larger oxygen molecules.

When my 6-YO and her buddy asked whether they could make slingshots this morning, so they could shoot stuffed animals at a tower of blocks, I couldn’t say no. It’s physics after all. A few months ago, my kids had a great time making slingshots with their plush Angry Birds, as you can see in this video.

We got out a chair, some rubber bands, and a plastic ring like the ones they put on prescription bottles. Within minutes, they were laughing hysterically while stuffed bunnies flew through the air. Click here for detailed directions on how to make the slingshots and to learn more about slingshot physics.

You can make colorful columns that demonstrate the concept of liquid density at your own kitchen table with just water, sugar and food coloring.  An eyedropper, siphoning bulb, syringe (minus a needle,) or anything else that allows you to slowly drip liquid from one cup to another are useful for the layering step.  If you have a tall, thin glass, like a cordial glass, or a test tube, it’s easy to see the layers in your gradient!

Start with two cups of hot tap water and measure half a cup into each of four cups. To the first cup, add 2 Tbs. sugar, to the second add 4 Tbs. sugar, to the third, 6 Tbs. sugar and to the fourth, 8 Tbs. sugar.  Stir until the sugar dissolves. If the sugar won’t dissolve, an adult may microwave the cup for 30 seconds and stir again. Always use caution with hot liquids. If the sugar still won’t dissolve, try adding a Tbs. warm water.

Now, add 2 drops food coloring to each cup. We added red to the cup with 2Tbs, yellow to the one with 4Tbs, green to the to the one with 6Tbs, and blue to the cup with 8Tbs.

Density is mass (how many atoms are in an object) divided by volume (how much space an object takes up.)  Sugar molecules are made up of lots of atoms stuck together.  The more sugar you add to a half cup of water, the more atoms it will contain and the denser it will be. Less dense liquids float to the top of more dense liquids.  Which of your sugar solutions is the most dense? The one with the most sugar in it (8 Tbs.)

Put the most dense sugar solution(blue in this case)  in the bottom of a tall, thin glass or test tube.  Now, use your dropper to gently drip the next densest liquid (green) on top of the blue layer.  It works best to drip the sugar solution against the side of the cup just above the surface of the liquid.  You can also drip it onto the back of a spoon, like in the photo above.  Add the yellow layer, and finally the red layer, which only contains 2Tbs sugar per half cup and is the least dense.

What happens if you mix the layers up? They won’t separate back out like oil and water would, because the sugar will disperse (spread) equally through the mixture.

Researchers sometimes use density gradients to isolate different parts of cells by breaking the cells up, putting the cell debris on top of a density gradient and spinning it in a centrifuge.  Cellular fragments of different shapes and molecular weights move through the gradient at different rates.

It’s holiday card season, and that means…film canisters!

When you’re picking up your photos, ask to dig through your camera or photo store’s film canister recycling bin. Pick out clear film canisters with lids that pop IN tightly, and you’ll be ready for some rocketing good times.

Make some film canister rockets to shoot off next spring, or brave the cold to shoot them off now. Do you think the chemical reaction that makes CO2 gas to power your rocket will take longer in the winter? Why?

Here are directions for how to make them. They’d be great holiday gifts for kids to make for siblings!

I almost always have a sprouting potato or two around my kitchen. I’ll buy a bag of spuds and only use part of it, leaving the rest to turn green and eventually end up in the compost.

Luckily, those orphan potatoes are perfect for a few science experiments. One teaches you a little bit about physics as you watch an object in motion (a drinking straw) remain in motion as you drive the flimsy plastic deep into a potato. The other, a potato maze, teaches you a little biology as you think about what a potato needs to grow.

We’d stabbed a straw into a potato before, but it worked shockingly well with the boiling potatoes we got from our farm share. The straws went all the way through! Click here to learn how to do the potato experiment yourself!

To make a potato maze, all you need is a sprouted potato, duct tape,some cardboard and a shoe box (or any cardboard box with a lid.) Cut out cardboard pieces the same depth as the box, tape them together, bend them and tape them inside of the box to create a maze.
Try to keep the walls of the maze the same height as the box and be sure to cut an opening at the far end of the maze so that light can get in at one end.
Put a sprouted potato or two in the maze. Close the box and seal any light leaks (other than the opening) with tape. (See photo at top for an idea of how your maze should look, but they’ll all be different and there’s no “right” way to make your maze! Just make sure there’s a direct tunnel between your potato and the opening!)

Place the box somewhere where it will get plenty of bright sunlight pouring into the opening. Wait a few weeks and check your potatoes. (You can check them more often if you’re impatient, but they won’t grow any faster.)

What happens to the potatoes?

They should grow towards the light, since plants need light to grow. Using a process called photosynthesis, they can change sunlight, carbon dioxide, water and minerals into electrical and then chemical energy, which allows them to grow into food for other living things. In the process, they also give off oxygen, the gas that we breath.

How do you your potatoes grow without food and water?

There are nutrients and water stored in potatos that allow them to start growing for a while without soil and water.

My kids brought “Angry Birds” to life this morning by making Marshmallow Slingshots and using them to launch their Angry Birds stuffed animals at a tower of blocks (with a stuffed pig on top, of course.)
Love it!!!
To make your own angry birds slingshot, all you need is a chair, some rubber bands, and a plastic ring like the ones they put on prescription bottles. Click here for directions and to learn more about slingshot physics.