You can’t read a parenting magazine these days without coming across the acronym STEM – science, technology, engineering and mathematics. We all know it’s important to expose our children to these disciplines, but do you ever find yourself feeling a little intimidated or overwhelmed? Never fear! STEM activities can be easy to pull off and super fun! I’ve compiled three great ones for you to try at home this summer. The projects are good for all ages – younger kids will just require more parental involvement.
EXPLODING WATERMELON
Nothing says summer like watermelon… unless it’s exploding watermelon! This experiment will have your kids thinking you’re the coolest parent on the block. You’ll need a watermelon, 400 rubber bands, safety goggles and a bowl or pot.
Place one end of the watermelon in the bowl or pot to steady it, ideally on a table. Now, place rubber bands around the middle of the watermelon, directly on top of each other. Once you reach about 200 bands, your child should stand back while you place the rest (typically 300 to 400, total). Remember to wear your goggles! You will notice the watermelon starting to bulge and then it will finally explode.
Why does it work? A watermelon rind is a rigid structure. The rubber bands apply force to the rind, causing its shape to change. The pressure builds within the watermelon until the melon splits and the pressure is released with force.
HOMEMADE LAVA LAMPS
You’ll need a tall plastic or glass bottle with a lid, vegetable oil, water, food coloring, a funnel and Alka-Seltzer tablets.
First, fill the bottle 1/4 of the way full with water. Now, add the vegetable oil until the liquid is approximately 2 inches from the top of the bottle. Allow it to sit several minutes until the oil and water are completely separated. Next, add 10 drops of food coloring to the bottle. At first, the drops will sit at the oil/water boundary, but eventually they’ll break through to the water. At this point, your child can give the bottle a GENTLE swirl to ensure that the food coloring is mostly incorporated with the water.
Now comes the exciting part! Leaving the top off the bottle, drop one Alka-Seltzer tablet into the bottle and observe your very own lava lamp! You can repeat the process or, once the bubbles are gone, you can cap the bottle and save it for another time.
Why does it work? Density is the measure of how compact a substance is. Because water is denser than oil, it sinks to the bottom of the bottle. Instead of using heat from a light to change the density of the liquids, this lava lamp uses Alka-Seltzer. The Alka-Seltzer reacts with the water and produces carbon dioxide gas bubbles, which stick to the water droplets. The water/gas droplets are less dense than the oil, so they rise to the top of the bottle. Once they reach the top, the bubbles pop. Without their carbon dioxide partners, the water molecules are once again denser than the oil and begin to sink again.
MAGIC EGG TRICK
This experiment introduces the concept of air pressure. You’ll need several peeled, hard-boiled eggs, one glass bottle with an opening of 1.5 to 2 inches in diameter (smaller than the egg), several strips of paper, vegetable oil and a lighter or matches.
Start by smearing a little vegetable oil around the mouth of the bottle to act as a lubricant. Next, ask your child to get the egg into the bottle without breaking it. Because the egg is wider than the mouth of the bottle, this task will be impossible.
Now, have your child hold the egg while you light the end of the paper strip and drop it into the bottle. Your child should quickly place the egg vertically over the mouth of the bottle. The egg will be drawn into the bottle whole.
Why does it work? The burning paper heats the air molecules inside the bottle, causing them to move farther away from each other. Some molecules will escape, sneaking around the egg. When the flame burns out, the air in the bottle begins to cool, and the air molecules once again move closer together, making room for new air molecules — this is called a partial vacuum. Usually, the air outside the bottle would move inside to fill the new space, but the egg is blocking the way. The pressure of the air molecules outside the bottle trying to move into the bottle is so great that it actually “pushes” the egg into the bottle.
-We all know it’s important to expose our children to STEM, but do you ever find yourself feeling a little intimidated or overwhelmed?
Alison Bogle is an Austin-based freelance writer and mom of three.
