Nicole has worked for HMNS in some capacity since 1996, whether part-time, full-time or as a volunteer. She taught for seven years in public school, including four years in Fort Bend and a short stint overseas. While she never taught science, she was always the teacher called when someone needed to remove a swarm of bees, catch a snake in the playground, or get the bat off the ceiling of the cafeteria.

# Ice cream science: Make a cool treat to beat the summer heat

It’s getting to that time of year when it’s so hot and yucky outside that everything cold is better.

It’s also a time for telling kids about how, when you were their age, if you wanted ice cream you had to turn a crank until your arms fell off (presumably while walking uphill to school both ways and fighting off bears…).

Here in the Houston Museum of Natural Science education department, we have tried making ice cream in a variety of ways to see what is easiest for kids, and not all ways are equal. (Pro tip: Those special ice cream-making balls they sell for kids freeze shut, and then kids are sad. Not recommended.) Our favorite way, at the end of this post, is fairly cheap and easy and fun for kids, but before we get to the instructions, let’s talk about some science.

To make ice cream, you will of course need ice. The ice is simply to lower the temperature of the cream to the freezing point, but if you just used ice alone and let it sit, you’d end up with a solid block of cream – more like an ice cube – and it would take longer to freeze. What makes ice cream special is salt and stirring.

Water freezes at 32° F, but sprinkling salt on the ice lowers the freezing/melting point of water. How, you say? In order for liquid water to freeze to solid ice, all of the water molecules have to slow down enough to connect to each other and form solid crystals. When this happens, the water loses kinetic energy due to the decrease in movement of those molecules. Because temperature is a measurement of kinetic energy, this results in a lower temperature.

The presence of salt interferes with this process. The water molecules can’t attract each other as easily because they are also attracted to the sodium and chloride ions from the salt. Mixing the salt, ice, and water together results in a temperature below the freezing point of water, which helps the cream freeze faster. The shaking or stirring helps cool the cream evenly and efficiently. In ice cream, this lower freezing point turns the fats into solids, but the water content to be almost frozen.

What about the milk, then? It is much easier to make ice cream with creamer, heavy whipping cream, or half-and-half than to use skim milk because of the higher fat content in cream. You can make ice cream with skim milk, but it is really, really, really hard to do by hand, AND you have already committed to making ice cream, so I feel like you have acknowledged the inherent risk of fat consumption that comes with making a frozen confectionery delight. Just use the full-fat stuff, and let’s all move on.

What does the fat do, anyway? Primarily the higher fat content allows for a richer, creamier texture and a more delicious flavor in your finished product. The reason for this is that when you are cooling and mixing the cream, you are also introducing air molecules to the liquid. The bits of fat in the cream add a little structure to the ice cream and trap these air molecules in the solution as it forms. This, plus the lower freezing temperature, enables you to be able to scoop the ice cream fairly easily because it allows for there to be a bit of unfrozen water in the ice cream, which stops the ice cream from becoming a solid block of ice.

If you have ever had ice cream that has grown ice crystals and gotten a bit of freezer burn, those ice crystals appeared because the unfrozen water in the ice cream had a chance to migrate a little bit when the ice cream was warmed slightly on the ride home or when it was left on a counter a little too long and then frozen again. There are things called stabilizers added to your ice cream to prevent this from happening. Most ice creams today have one of five stabilizers added to them: carob bean gum* (a type of bean from Africa), carrageenan (a type of algae), guar gum (a type of legume from India), sodium alginate (made from seaweed) or carboxymethyl cellulose (sounds scary but it’s plant-based). Often, if you read the label, you will see more than one of these in your ice cream to keep it smooth and delicious.

* Carob beans, or locust beans, are cool. They are from exotic African trees and each bean is so similar that at one point they were used as a unit of measurement for gold and silver. We still use this measurement today, but the name has changed over time to Karat.

So now that you have had a little lecture about the science of ice cream, let’s get to the delicious lab work.

Activity: ICE CREAM!!!!

Materials:

Individual serving containers of coffee creamer

Ice

Small waterproof container or quality sealable plastic sack big enough for about two or three cups of chipped ice

Salt, any variety

A dish towel to insulate your hands

Optional: Inexhaustible energy of small child-based labor

Procedure:

1. Find some liquid coffee creamers in individual pots.
2. Put ice in your water proof container, filling it about a third of the way. Smaller chunks of ice work better because there is more surface area, but any ice will do.
3. Layer your salt on your ice. Several solid sprinkles will do, but if you are nervous about the quantity, add some extra just in case. It won’t hurt anything.
4. Put your sealed creamer cup(s) in your container and then put more ice in, filling it about 2/3 of the way.
5. Layer on more salt.
6. Finish filling the container with ice.
7. Start shaking your container. Make sure it is well sealed and that you have a firm grip on it. No one wants to be injured in an ice cream-related accident. There is no way to spin that so it sounds cool. Also, this is an excellent job for kids to help with. Put on a nice, long song or two and let them wiggle till they drop. About ten minutes will do it, but you will know when you are getting close because a frost will form on the outside of your container. If you don’t feel frost forming after a couple of minutes, add more salt. To speed this process up, start with creamer pods that have been stored in the fridge. This way, your creamer will start at about 50° F, and you won’t have to work so hard.
8. After about 10 minutes of shake, shake, shaking your ice cream, dig your creamer cup out of the ice and wipe it off.
9. Ta dah! You are done. Unless you want to make this tablespoon of delicious homemade ice cream into a sundae and add chocolate and banana or some jelly for more flavor.

Note: If you are thinking to yourself, “That seems like a lot of work for a tablespoon of ice cream,” well… it is. But it’s also science. So there.

If you get the liquid creamer that comes in a larger container at the grocery store, you can increase the volume of your creamer and make MORE ice cream. If you choose to do this, you will need to find a small waterproof (and I would suggest plastic) container to pour the creamer into and then a slightly larger waterproof container for all the ice and the salt. It’s the same procedure, just with a larger amount of the ingredients!

# Take It: HMNS shopping trips rival Liam Neeson’s shakedown

May is upon us, which means it is time for stocking up on mosquito repellent and sunscreen, flip flops and floppy hats, bathing suits and beach towels. For the education staff at the Houston Museum of Natural Science, it also means heavy lifting and preparing for the emotional gauntlet that is summer camp shopping. Julia does the bulk of the mass ordering, but there are some things we just have to go to a brick-and-mortar store to get. So off to the store we go! Usually three or four hours at a time.

Generally, when we get to the store we take it. We take it all. Just like Liam Neeson.

The most common quantity on a shopping list is “all of them.”

We are like a plague of locusts, actively demolishing orderly displays of stock, leaving only a husk behind. If you are the unfortunate person who comes behind us looking for just one single solitary bottle of green food coloring, I’m sorry. Because I took them all.

Inventory before HMNS hits…

…and after.

On this particular trip, we start in what we affectionately refer to as, “bathroom.”  This is all the stuff that you might keep in your medicine cabinet, make-up drawer or shower. It’s a fairly small section in our shopping adventures, but it almost fills a basket by itself. “Bathroom” is a weird mixture of heavy items and small items. They have a tendency to sneak out through the holes in the bottom of the basket if you aren’t keeping an eye on them.

We need all the cotton balls!

That white box? It’s an entire container of cotton balls. Why? Because we need them all.

After about an hour, in which Julia and I cover “bathroom,” “appliances,” and “party” (and I’d like to point out that it’s always a party in our department), we take a short break and check the list before heading to “craft” and “office.” There is no lunch break until the basket is full. Once we reach the point of having to carefully place items so they won’t fall out of the basket, trailing behind us like breadcrumbs, we decide it’s time to stop for lunch.

With special permission from Josh, the assistant manager, and promises from the clerks that no one will try to put our treasures away, we drop our first basket near the front and head for a quick “strategy meeting” (which is actually code for lunch), which allows Julia to double-check the list. Again. For the fourth time.

“I don’t know who you are.  I don’t know what you want. But if you are looking for Raisinets, I can tell you they don’t have any.”

Our summer camp uniform shirts are navy blue. This also happens to be the uniform shirt color for employees at one of our frequented summer camp shopping spots. This coincidence combined with the fact that our shopping basket is always filled with nonsense, and plenty of it, ensures that we will be confused with store employees at least once during any excursion. I have discovered that it is often easier for everyone if I can just tell the confused shopper where the item they are looking for is located. Due to the fact that we often need so very many weird things of specific shapes and sizes, I can almost always tell them if the store has it in stock and where to find it.

When customers come up to me asking where they can find an item, I just tell them; I know where almost all of it is, anyway.

On this trip, we are asked twice to lend a helping hand. The first time, it’s a guy looking for reading glasses (usually across from the pharmacy window), and the second is a corporate stocker looking for her product placement (Swedish Fish and Sour Patch Kids – on the bottom shelf next to gum). We have been asked to locate anything and everything including, but not limited to, powdered sugar, colored ping pong balls, decorative masking tape, Abuelita chocolate, and picture-hanging supplies. (In this particular instance I recommend 3M Velcro strips, at the very end of the hardware aisle.)

My favorite case of mistaken identity happens while shopping with Sahil. He and I have spent many a summer’s day at the store shopping for 12-inch yellow balloons (with birthday party supplies) and Cheez Whiz (usually in the cold cheese section, which is weird because it doesn’t actually need to be refrigerated). Usually when shopping, we make a list by section – garage, craft, clothing, etc. – and then divide and conquer with one of us on aisle 10 and the other on aisle 11. Because Sahil is so very nice and polite, I have come around the corner more than once, turning slowly because my basket is so full, and see him helping a customer reach an item on the top shelf or discussing the merits of the three coolers in front of them.

On one particular occasion, we’re short on time, so Sahil‘s concentrating on the list in front of him, determining what we have left to find, when a customer comes up and asks him for the location of the honey, which stumps him. Honey isn’t something we’ve purchased before, so Sahil politely tells the customer that he doesn’t actually know where the honey is located. He apologizes and goes back to his list. The customer insists he help her, but he again tells her he doesn’t know where the honey is. He suggests it might be in the breakfast aisle, maybe with syrup, and again goes back to his list. The customer, feeling she’s been ignored, reports him to the store manager who then comes to chew Sahil out, the “unhelpful store employee.”

Oh, summer camp

“But what I do have is a very particular set of skills… Skills I have acquired over a very long career. Skills that make me a nightmare to people like you.”

When I was a child, my mom and dad purchased Nintendo Game Boys for my brother and I from a neighbor at a garage sale. I had two games I played regularly, Dr. Mario and Tetris. I was super good at both. We weren’t allowed to play our Game Boys a lot, but they were encouraged on road trips. I would play one of those two games for miles and miles, laying on the floorboard in the back of the sedan so my older brother could have the bench seat. Despite what my mom said, playing these games did not rot my brains out, though I do remember on more than one occasion, at the end of a long day of driving, dreaming of dropping pills and “tetrominoes.”

What seemed a pointless game for children has turned into a useful and particular skill as an adult.

I don’t love shopping. Never have. This combined with my Type A personality traits and the fact that shopping carts can only hold so much means that I have turned camp shopping into a game of sorts: Tetris – Museum Edition.

Tetris: Museum Edition

When filling a cart, one should start with heavy and square items on the bottom, filling the gaps as the occasion arises. Hydrogen peroxide, for example, leaves just enough of a gap in the basket that you can tuck in your petroleum jelly to fill the space. When you have established a base layer, it’s time to start building side walls. These are the ramparts, allowing you to generate volume in the basket without an avalanche of Q-tips. Finally, top off your basket with bags of things to cement all the layers together. Generally, heavy bags work best, such as bags of candy, but use what you can. Once your basket can’t safely hold another item, it’s time to head to the check-out.

I’d just like to apologize to any check-out clerk that has ever helped me during summer camp shopping. They see us coming, with our two or three carts packed to the rafters, and the audible sigh can be heard three lanes over. We try not to be too irritating, but we know we are. The standard speech to the clerk goes something like this, “Hello (insert name here). We are making a tax-exempt purchase today. Whenever possible, we will put like items together for ease of counting. My colleague has gone to get an empty basket to help you out.”

Car Tetris…

Inevitably when we check out, we end up with way more output than we had input due to my mad Tetris skills. On this particular trip, we have a one-to-two ratio of pre-check out baskets to post-checkout baskets, which I kind of consider a failure on my part. I think I could’ve done better. In my defense, this is just the first shopping trip of the season, and I haven’t stretched.

…showing my particular set of skills.

Next comes car Tetris, where you take all of your goodies out to your vehicle of choice and build a mountain of things. As with the cart, you must start with the square and heavy items, then slowly build up to the items that can be crushed or smashed. On more than one occasion, I set my heights a little too high and have to pack stuff around my shopping companion. Today, the four baskets of treasure fit quite nicely into Julia’s back seat.  According to Julia’s Instagram, #wehadmoreroom.

The final stretch of any shopping trip is reverse Tetris, where the supply vehicle is met at the loading dock by all the worker bees, and we unload and sort the treasure. Depending on the trip, this could go a number of ways. We could sort by camp requests, by storage area, by weight, by refrigeration needs, and so on. Today’s trip?  We sort by storage location because, starting next week, we have INTERNS coming and we don’t want to deprive them of the opportunity to figure out where all this stuff goes!

Reverse Tetris begins…

…and game over. Now time to let the interns sort it out.

“If you have a case of glow-in-the-dark paint in the back, that’ll be the end of it. I will not look for you. I will not pursue you. But if you don’t, I will look for you. I will find you and I will bother you repeatedly.”

One of the trickier parts of camp shopping is when we need it, we need it now. If the store is out of stock, you go to another store. If that store doesn’t have it, you try at another place. On the hard-to-find items, we try to buy ahead or find a place we can order them, but that doesn’t always work, particularly if we are looking for a specific item for a specific purpose. Occasionally, even when there is a source for an item, we will run short and it becomes an emergency thereby causing us to hoard said item for years. I remember with dismay the Button Magnet Shortage of 2010 and the Silver Tinsel Crisis of 2008. Those were dark times… Dark times indeed.

Because there is a limited amount of time and a limited number of places, we have learned to be persistent. We ask questions. We know you have it in stock in the back… Please go look… And the poor clerk that runs into our brand of crazy, usually doesn’t understand our request.

HMNS camp shopping isn’t for the faint of heart.

“How many do you want?”

All of them.

“But there’s like 50.”

Yes. All of them.

This style of shopping takes a minute to get used to and isn’t for the faint of heart or weak of muscle. And, once the summer has ended, you have to transition back to your normal life. Sahil, former shopping partner and current Outreach presenter, has fallen victim to this trap more than once. While at the store with his mom shopping for a big family dinner, he was sent off to get enough refried beans to feed 12 people. He returned with 12 cans.  His mother was not amused.

Our persistence usually pays off and, at the end of the day, we return victorious with the last carnivorous plant in town (or whatever the item might be).

# Educator How-To: How to Make Your Own Pet Squid

The days just after Thanksgiving are always busy at the Museum. There are flurries of children on field trips, shoppers looking for that unusual and prefect gift and, my favorite, the annual installation of the holiday trees in the grand hall. The trees, which are decorated by local area non-profits, celebrate a variety of themes and causes and are not to be missed. My particular favorite each year is the tree decorated by the Houston Conchology Society. My department also gets to decorate a tree and it is always an ode to science. This year’s theme: Cephalopod Christmas. How can you go wrong there?

We know you will be out to visit the trees this year, and we assumed that you would want a cephalopod for yourself so I whipped up this little tutorial for your very own pet squid.  He’s adorable. He’s a cephalopod. Most importantly, he doesn’t have to be fed, walked* or cleaned up after.

(*You might look really awkward trying to take your cephalopod for a walk.)

Materials:

1 Paper towel tube
1 Toilet paper tube
Paint – color of your choice
Paint brush
Scissors
String, yarn or thin ribbon – 2 to 3 feet.
Tape
Straw
Glue
Black permanent marker
Stapler

Procedure:

1. Color your tubes with the paint of your choice. (Don’t clean up the paint quite yet. You’ll need it again in a minute.)
2. Set the tubes aside and let them dry.
3. Pinch one end of the toilet paper tube shut.
4. Use scissors to cut a 45 degree angle off each side of the tube so you now have two triangle pieces and a pointy tube.
5. Use a stapler to keep the tube flat. I aligned my staple with the length of the tube so as to not get in the way of the next step.
6. Use the scissors to cut 8 legs from the paper towel tubes. The legs should go up the tube about 2/3 of the way.
7. Use the rest of the paint to color the pieces you cut off – both sides and the inside of the legs you just cut. The legs may get a little floppy when they are wet with paint, but don’t worry – they’ll firm up when dry. If you have some weird delaminated bits, you can always add a little bit of glue.
8. Once everything is dry, cut one of the triangle pieces down the fold so you have two pieces. Cut the other triangle piece into two feeding tentacle pads.
9. You are going to use the halved triangle pieces to make the fins of your squid. Apply a little bit of glue to the hypotenuse of the two triangles (opposite the 90 degree angle) and slide them in between the two pointy bits of the toilet paper tube – one on each side.  The 90 degree angle should be the part sticking out and making the fin.
10. Now grab the paper towel tube. Use the scissors to shape the legs as you see fit. I like mine a little bit more realistic but, really, you can leave them as is.
11. If you so choose, you can also curl or shape the legs for more realistic appearance. For mine, I did this by rolling the legs over a round marker – switching from the inside of the leg to the outside of the leg every so often.
12. Now, glue the feeding tentacles to the string. You can also staple or tape them on as you see fit. Go crazy.
13. Tie the middle of the string into a small knot. This will give you a little bit more material when you attach the feeding tentacles.
14. Holding onto the knot, drop the feeding tentacles down through the uncut end of the paper towel tube.
15. Staple, glue or tape the end of the knot to the edge of the paper towel tube to secure it in place.
16. Cut a 2 ½” to 3” slit in the uncut end of the paper towel tube. This will allow you to overlap these edges and fit the “legs” into the “head”.
17. Now let’s make a siphon. Cut a straw slightly longer than your slit. Let’s say 3 ¼” just for fun.
18. Flatten the straw a bit and then attach the straw to one of the edges of the slit you just made.
19. Curl the side of the slit without the straw behind the side of the slit with the straw. Then, fit the “legs” into the “head.  Push it all the way in.
20. Once you know it fits, take the “legs” out, put a little glue on the top edge and fit it back into the “head”.
21. Last step! We need to add some eyes! Using your black permanent marker, make two dime sized circles on your guy on the “leg” piece between the “head” and the legs.  They should line up approximately with your fins.
22. Done! Enjoy your pet squid and take him on lots of walks to the park.  Squid love going on walks. Here’s the final product.I have named him Maurice.

# Educator How-To: Be your own knight in shining armor with homemade chain maille

When people think of knights, they generally think of armor, too. The plate armor most associated with knights was actually a fairly recent invention. Armor started as quilted shirts and thick leather pieces to cover arms and legs (if you were fortunate enough to afford it!).

Chain maille was a pretty fantastic innovation for the time, but it had its drawbacks, too. It was heavy and cumbersome and only as strong as each individual link. Because the links were made of steel or iron, they rusted quite readily, and those rusty links were the proverbial “chinks in the armor.” They were points of weakness that might allow a sword point or arrow to penetrate.

The job of armor maintenance was given to young boys that might otherwise be underfoot. To start, the armor was placed in a barrel of sand and sealed up. The boys would then roll the barrels back and forth across the yard and the sand would scour the blood and sweat and rust off the links. Even a well-maintained chain maille shirt would need repairs quite often and the color on even the best of days would be a dull dark gray.

Further innovations led to the plate armor that we know today, but even then, it wasn’t always so shining. Here is a suit of armor that belonged to Henry VIII.

Beautiful? Yes. Well-crafted? Yes. Shining? Not so much.

Don’t be fooled into thinking that body armor like this was a strictly European invention.  Most cultures that engage in warfare have some sort of armor to counteract the weapons. Some of the armor is ceremonial, but more often than not, it is clever and particular to the local environment.

The Maya and Aztec, for example, wore knee-length jackets of tightly-woven quilted cotton called ichcahuipilli. The jackets were soaked in salt water and then the water was allowed to evaporate. The salt left behind would crystalize between the quilted portions of the jacket, creating small, thick, sturdy plates of protection which were effective against arrows, atlatl darts, obsidian swords and batons.

They didn’t have cotton in Micronesia, so on the islands of Kiribati, they used what they did have: coconuts. Helmets, leg coverings, shirts and chest protection were made from tightly-woven coconut fibers as protection against another natural resource: sharks (or more accurately, shark teeth). The teeth of the sharks were drilled in the roots and then attached to the base with bits from the veins of the coconut leaf or human hair. The shark-tooth swords were intended to disembowel an enemy or open a major artery so he would bleed out. Yikes!

Want in on all this exciting armor action? You’ve got two options!

Option 1: Bring your crew down to see Magna Carta before it leaves on August 17th.  You have three short weeks! If you want to bring a school group or day care, be sure to contact fieldtrips@hmns.org to get the school rate. You will also want to consider coming on a Friday mornings at around 11.

Option 2: Can’t make it to us? Then try your hand at making your own armor. Sort of.  Here’s a pretty easy chain maille bracelet you can make at home. It won’t offer you much protection but it will allow you to practice your technique before trying something a little more complicated.

Materials:

-Jump rings or chain maille rings (The bigger they are, the less work for you.)
-The clasp of your choice or a piece of leather or ribbon to tie the bracelet ends together
-2 pairs of jewelers pliers (or needle-nosed pliers if you are in a pinch)
-A tape measure or piece of paper to measure your wrist

Procedure:

1. Measure how long you want your bracelet to be using a tape measure (or even a piece of paper). The standard size for women is about 7 inches and the standard size for men is about 8.?
2. Open several of your jump rings. To open them, you DON’T want to pull them apart.  Instead you want to twist them open. If the individual rings start off as an “O” shape, you don’t want to make them into a wide-mouthed “C”. Instead, you want to slide the ends away from each other, one towards you and one away from you. Because of the way the rings are made, they naturally take that shape, so that should help you get started. If your rings lay flat when opened (rather than in a twisty shape), you will need to try again! Once you have a pile of open rings, things get a little trickier. You can keep up though. I believe in you.?

3. The next step is to put four closed rings on an open ring and then slide the open ring back into the closed position. Then repeat this step over and over. You will need probably 10 of these 4-in-1 sets for a 7-inch bracelet.

4. Once you have the 4-in-1 sets made, you will need to use your pliers to separate out two rings from the four. The set should hang from your pliers as two rings, with one ring in the middle and two more rings at the bottom. You are then going to feed an open ring through the top two rings. Shift your pliers around so that you are now holding onto that open ring.?

5. Using your other set of pliers, pick up two rings on another 4-in-1 set. Loop those two rings through the open ring (effectively creating a new 4-in-1 set) and then close the open ring. You should have created a small chain at this point. Great job!

6. Repeat steps 4 and 5 until you have 4 or 5 small chains. I am doing 4, but I have pretty small wrists.

7. Getting close to being done! You will need to link these small chains in exactly the same way you did the sets. Take two rings from the top of one small chain and put them on an open ring with two rings from the top of another small chain.
8. Now, repeat step seven with your longer chains!
9. Finish up by adding a single jump ring to each end. This will let you tie the two ends together, or you can add a clasp to that last ring before you close it up. You’re done!