How to Teach Your Kids Science and Engineering

Our K-12 Engineering Outreach Office Shares STEM Lessons You Can Do at Home

We are all concerned about the current health climate, but for those who have children at home or know of children who are home, finding easy-to-do activities can be a challenge. UD K-12 Engineering is here to help. Each activity is geared towards exploring a foundational concept with help from expert faculty at UD.

Weight and Density – Multidisciplinary Exploration

Weight and density figure into many topics of research. One researcher, Tobias Kukulka, associate professor in the School of Marine Science at UD, works on the interplay of objects in the ocean and the currents that carry them that lead to the plastics amassing in the ocean. Try these experiments to explore some concepts in his research.

PreK and Kindergarten – Exploring weight through gravity

You can test the weight (the gravity and mass of an object) of some outside objects by putting varying items into a laundry basket and shaking the basket. The heavier items will sink to the bottom. For example, put leaves into the basket. Put sticks on top. Shake the basket. The sticks fall to the bottom. They have more weight. You can try recycling bottles and tennis balls. The combinations are endless.

Elementary – Everybody loves a rainbow

glass showing different densities of liquids Using sugar, water and food coloring, you can examine the concepts of concentration and density by making a density column. In four separate cups, add 1 Tablespoon of sugar (in first cup), 2 tablespoons of sugar (in second cup), 3 Tablespoons of sugar (in third cup), and (you guessed it) 4 Tablespoons of sugar (in fourth cup). Now add 16 ml of water to each (using a medicine dosage syringe or a metric measuring cup). Then, mix each cup until the sugar has dissolved into the water. Now, add one drop of red (1st cup), 1 drop of yellow (2nd cup), 1 drop of green (3rd cup) and 1 drop of blue to last cup. Gently mix color. Adding blue (heaviest) first, stack the colors into a small, clear glass container (thin vase, juice glass or similar), in order of weight (blue, green, yellow, red). The reason why they stay in this order is due to their density. The amount of water is the same, but each color layer has a different concentration of sugar.

Middle School – Experimentation of water density and the ocean currents

Try the above activity with salt.  Do you get the same results?  Research the varying density of the sea water in the ocean.  How do the layers of the ocean also vary in temperature?  Kukulka tells us this:

“A layered density structure (called stratification) is absolutely critical for sea water and essential for ocean dynamics! In the ocean, density is mainly determined by salinity {the amount of salt in the water}, temperature, and pressure (density increases for a cooler, saltier oceans and with greater pressure).”

ocean weight and density

(c) Tobias Kuklka


For more examples of weight and density concepts, see this link.  For a scientific exploration of density of water and density try this lab by the MERL (Microbial Ecology Research Lab), here at UD. You can explore more of Kukulka’s through this video.

Surface Tension and Water

Learning about basic concepts such as surface tension in water helps pave the way for examination and exploration of materials, chemicals, living creatures and environments – all critical to engineering. Here are some ways you can experiment with this concept.

Pre-K and Kindergarten – Plastic film and Surface Tension

Use a 6-foot (social distance length) piece of clear plastic wrap. Place dried beans or pasta on the wrap. You can bounce the beans or pasta on the film as an illustration of how the surface of materials can behave differently than the rest of the material. When they bounce off the wrap, that’s like a hydrophobic (literally, “afraid of water”) substance. An example of a hydrophobic substance is oil, which you can see in many salad dressings in the form of separation.

Elementary School – Examining Surface Tension, “The Old How Many Drops on a Penny” Trick

The molecules on the surface of the water keep outside things from entering the water. They arrange more tightly than the molecules not on the surface. Take a penny and some water and a dropper. Estimate how many droplets will stay on top of a penny (and note the shape). Was your hypothesis lower than your result? What shape did the droplets take as you added them one by one?

Middle School – Soap, Water and the Surface Tension of Water

Pour about half an inch of water into a pie plate or small bowl. Add a sprinkling of black pepper on the top of the water. It floats because the molecules on the very surface are keeping the pepper from entering the water. You can impact the surface tension by adding a drop of dishwashing liquid. Liquid soap like this can impact the surface properties of the water. It’s even called a surfactant.

Surface tension in a water droplet


Soap breaks water tension


For more surface tension demonstrations and activities, see this video by The Physics Girl.  For a scientific experiment using surface tension, see this link by Chemed.

Hydrogels – They are Everywhere in Engineering

What are hydrogels? What do we do with them?

Darrin Pochan, Professor and Chair of the Department of Materials Science and Engineering at UD,  gives us some answers.   “Hydrogels let you turn a liquid into a solid without freezing it.  Try holding a kilogram of water in your hands. Very difficult!  Put only 5 grams of a gelling agent into the water and the entire kilogram of liquid turns into a solid.  But not a frozen solid (that has crystallized).  Rather, the 99.5% water system is somehow trapped within a net and unable to escape-a quite good magic trick!”

So, how do hydrogels figure into your research, Pochan? “We quickly realized that these materials could be great for growing cells into tissues or for encapsulating and delivering drugs to human patients,” he said. “We can trap whatever we would like in the gels and then deliver them to human bodies for therapy since one is pretty much only adding water-a very biocompatible system.”

PreK–Kindergarten – Hydrogel You Can Eat

A liquid holds the shape of its container.  A solid holds its own shape. A hydrogel is neither a solid nor liquid.  Play with some water when you pour it onto the sidewalk what shape does it have, if any?  In a glass, what shape does it have?  Examine solids like bread, crackers or any fruit.  If you put a banana in a pitcher, it is still banana-shaped, right?  You could force it into that shape, but it will not do It on its own.  NOW, let’s add a liquid (water) to a solid (gelatin mix).  After it cools and is set, you have your very own edible hydrogel.  It doesn’t pour like a liquid or take the shape of its container.  It isn’t really a solid and holding its own shape.  It takes the shape of whatever you put it in BUT it holds a shape in a spoon.

Elementary School – Dissecting a Diaper

HydrogelsThis is great because you get to interweave the function of diapers (giggle) with actual Engineering.  Cut a 2-inch by 2-inch piece of diaper out of the between the legs section of any diaper.  Can you see the tiny white particles in this piece (DO NOT INHALE).  Put this diaper piece in a plastic sandwich bag that zip seals.  Before you seal it, get a dropper and a bowl of water.  Predict how many drops of water this little piece of diaper will hold (an hypothesis).  Now, drop one droplet of water at a time into the bag (do not squish the bag), onto the diaper piece.  Notice how the tiny, white particles have changed.  They should look bigger, clearer.  You’ll know your diaper piece is done accepting water when the droplet remains in the bag, not in the diaper piece.   How well did you estimate the amount of liquid the diaper piece would absorb?

Middle School – Bonds and Hydrogels

Do the above experiment with a diaper piece.  The material you are looking at inside the diaper is a hydrogel, which is hydrophilic (it likes water).  The water and polyacrylate (the tiny, white particles) come together with a hydrogen bond.  They crosslink (get entangled) to form the structure you see (the larger, cleared polyacrylate).  You can break this hydrogen bond by adding salt to the plastic bag with the enlarged polyacrylate.  Add a pinch of salt to the bag and GENTLY massage the salt into the diaper piece.  Notice what happens.  The water will begin to leave the polyacrylate. The hydrogen bond has been broken by the salt (sodium).

Virtual and Vernal

We also wanted to provide some virtual places to go and things to do.  The Smithsonian has made some of its holdings digitized and in 3D.  Take an up close and all-the-way-around look at some interesting items.  No lines.  No waiting.

Learn more comparative anatomy through virtual explorations of anatomy.  The National Anti-Vivisection Society has created a list of mostly free online anatomy lessons and dissections that affords the ability to gain the experience from home.

Visit another place with webcams.  The Monterey Bay Aquarium has jelly cams, penguin cams and great information about different species in their magnificent collection.   If you prefer the domesticated, the Farm Sanctuary has a live stream that gives you a barn experience without the shirt nibbling.

Explore bacteria culture by making yogurt with your yogurt.  The Exploratorium is just a click away with many at-home experiments online.

Gain a new skill operating a steam engine locomotive.  Jobs may be limited but this online training gives many of the virtual skills you will need to run a 1930s steam engine.

While we believe all engineers are civil, some are actual Civil Engineers, who build bridges and roads and more.  Try your hand at being a civil, Civil Engineer, using the West Point Bridge Designer.

Finally, thanks to Theresa Emmett, at FourYouth Productions a non-profit for STEAM programming in Wilmington, we encourage you to try this STEAM activity:  go on a scavenger hunt with a camera.  Ms. Emmett gives some suggestions.  Try taking pictures of and cataloging photos that illustrate the words : water, shiny, reflection, water, nature and pattern.  What do you know about these words and how they can relate to science and engineering.

Have fun and keep those neurons firing!

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