NEVER look directly at the sun, since you can permanently damage your retinas (the light sensors on the back of your eyeballs.)

Using a pinhole viewer, you can see the sun's image with the sun behind you!

That being said, you can safety view the sun with a shoebox by standing with the sun BEHIND you.  All you need is a shoe box without a lid, a piece of white paper, aluminum foil, a pin and tape. It’s perfect for viewing a solar eclipse, like the one coming up this Sunday.

A solar eclipse happens when the moon passes between the sun and the earth, blocking the sun from view. Go to this eclipse calculator to see when and where you can best view the eclipse with your viewer! Here in Minnesota, we’ll see a partial eclipse on Sunday evening.

First, tape white paper over one end of the shoe box (on the inside.) This is your viewing screen.

Then, cut a big notch out of the other end of the shoe box and tape aluminum foil over it.

Use a pin to poke a hole in the center of the foil.  If you mess up, you can always put new foil on and try again. The smaller the hole, the better the focus, but we made ours a little bigger than the actual size of the pin.

Now, stand with the sun BEHIND you. (See photo at top of post. The sun is behind her, high in the sky) NEVER LOOK AT THE SUN THROUGH THE PINHOLE ITSELF.

Hold the box upside down so the pinhole is pointed at the sun.  The idea is that the sun will shine through the pinhole and its image will be projected on the white paper as a tiny circle.

This was taken on a cloudy day when the sun peeked out, but you can clearly see the bright circle near the center of the paper.

Practice on a sunny day (or when the sun peeks out between the clouds) so that you know what to do when it’s time for the eclipse. Small children should be supervised so they don’t try to look directly at the sun.

You can do the same thing using two white index card, poking a hole in one you hold nearest to you and projecting the image on the one you hold away from you (with the sun behind you.)

Enjoy! Watching an eclipse in the 70s after my dad came to school and helped us all make these boxes is one of my earliest “science” memories!

Spring is finally here.  A fantastic way to enjoy it is to take a nature walk.  While you walk, watch for signs of spring and assemble your discoveries on your wrist with a nature walk bracelet.  It’s always a good idea to bring a few bags along too- one for larger treasures (like pine cones) and one for trash.  You can study nature and clean up the environment at the same time!

All you need is duct tape.  Cut the tape so it fits comfortably around your wrist and tape it around like a bracelet, sticky side out.  Take a walk in a park or down your own street and look for small leaves, acorns, flowers and other natural artifacts to adorn your wristlets.  Be sure to watch for birds while you walk!

We wore our bracelets all afternoon and several people mistook them for real jewelry.  My oldest daughter thought they looked even prettier as the leaves and flowers wilted and flattened out on the tape.

Enjoy!

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! We threw eggs on Kare11 Morning News last spring. It was pretty funny…and messy!

“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!

On April 21st (the day before Earth Day), the Science Museum of Minnesota will celebrate Earth Day and open their new Future Earth exhibit to the public.  Exploring the amazing planet that nurtures and sustains us, the thought-provoking exhibit examines climate science, looks at the impact of humans, and considers Earth’s future.  Today’s young people will play an essential role in determining that future, and it’s essential that we raise our kids to be critical thinkers, as well as creators and innovators! Abby Harrison, a.k.a. Astronaut Abby, wants to be the first person on Mars and she visited Kare11 Sunrise news with me to talk about NASA and Earth Day.

Every time you encourage a kid to ask “why?” or get them out into nature, you’re engaging their scientific brains!  When they see you recycle, turn out the lights, walk instead of drive, or pick up a piece of trash, you’re teaching them lessons about stewardship and responsibility.

Here are some easy experiments that would be fun to do with your kids to help celebrate Earth Day. If you click on the experiment name, it will take you to directions and photos!

Window Sprouts: Plant a bean in a plastic baggie with a damp paper towel and see how plants need only water and air to sprout roots and leaves.  Here’s a short video demonstrating how to put a window garden together.

Homemade Solar Oven: Using a pizza box, aluminum foil, plastic wrap, and newspaper, you can harness the sun’s energy to cook your own S’mores! Try it!

Nature Walk Bracelets: Wrap some duct tape around your wrist (inside out) and take a walk, sticking interesting natural objects like leaves and flowers to your bracelet. It’s a great way to get outdoors and engage with nature!

Carbon Dioxide and Ocean Acidity: See for yourself how the carbon dioxide in your own breath can make a water-based solution more acidic. It’s the same reason too much carbon dioxide in Earth’s atmosphere can be bad for our oceans.

Greenhouse Effect Experiment: With a few jars, plastic bags, ice, and a thermometer, you can demonstrate how greenhouse gases can trap heat in our atmosphere.

Composting: Be a composting detective. Bury some things in your back yard (away from power cables) and dig them up in a few months to see how they look. Composting reduces methane gas emissions (a greenhouse gas) from dumps.

Diffusion and Osmosis: See for yourself how chemicals we add to water, put on our streets to melt ice, and spray on our lawns and crops can move into our soil, ground water, rivers, lakes and oceans.

Solar Water Purification: Another great illustration of the greenhouse effect and a fun experiment in general.  Requires hot sun and some patience!

To continue to thrive, we’ll need countless innovations in energy, agriculture, health and environmental stewardship.  Our children are our greatest natural resource, and we will depend on them to make a better future for us all.  It’s up to us to nurture them, educate them, foster their innate sense of curiosity and fan their creative spark.  Happy Earth Day!

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 just need clear gelatin (from the grocery store or Target), food coloring and water.

Follow the instructions on the gelatin box for making finger jello, but don’t use any fruit juice so that it remains clear. 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?

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 and 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

warm water in jar on left, room temp in jar on right

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.

We’ve often used the water from boiling red cabbage to make Litumus (acid-indicator) paper, but last year, we used it to make egg dye!  Simply follow the directions here to make your cabbage “juice” and put hard boiled eggs in the cabbage juice to dye them blue.  It works best when the cabbage juice is still warm!  The juice turns pink when you add an acid to it, so when your eggs are dry, you can paint pink designs on them with lemon juice or vinegar using paintbrushes, toothpicks or Q-tips.  You can also dissolve baking soda in water (which makes a base) to add more color to the eggs (greenish-blue which shows up when they dry.)  Here’s a video of a demonstration I did on Kare11 news of this experiment.

Try some other natural egg dyes!  Boil colorful fruit, vegetables and spices with 4-8 cups water and a few Tbs. of white vinegar.  When the water is boiling, add raw eggs and boil for 10 minutes.  The pigment in the fruits and veggies will be absorbed by the egg’s porous surface as they cook.  Let the eggs sit in the dye until cool.  Then, wrap the wet eggs in onion skins or rub with paprika for yellow.  We had the best luck with blueberries, curry and red cabbage.  Experiment  to see what makes the best colors!  What worked best for you?  Coffee?  Tea?  rhubarb? Don’t forget to eat your creations.  Hard-boiled eggs make a great snack!

There was no school yesterday, so we went on a field trip of our own to the Science Museum of Minnesota.

We started the day by being transported “Under the Sea” at the Omnitheater, watching sea lions frolic and giant sea turtles gobble jellyfish. (Did you know they close their eyes each time they take a bite, so they don’t get stung?) The kids loved “Real Pirates” and filled out activity sheets to win eyepatches. They especially liked playing dice and looking at the different coins in the Treasure Room!

After lunch, they brought some fossils and flint they’d found in Kansas to the Collector’s Corner and then we spent the rest of the day playing at the museum!

The new wind tunnels, where kids could fashion flying machines from paper, cups and pipe cleaners were a huge hit! I wonder if we could figure out how to make one in our kitchen. Hmmm.

My son came home from school the other day joking about a zombie apocalypse. Before that, it was the Mayan apocalypse.  And now, he keeps hearing about all these “freaky” solar storms.  He laughs, but I’m sure his 11-year-old imagination leaves plenty of room for worry.

I can’t kill the zombies lurking in his subconscience, but I can put his mind (and my own) at ease about the solar storms with this short NASA video that explains that we’re in a totally normal sun cycle and are protected by Earth’s atmosphere