Blog Feed - Page 15 of 28

The Ice Cream Lab

Today was the day for everyone’s favorite lab of the year – the ice cream lab!

What is the Ice Cream Lab?

The ice cream lab is a fantastic, fun, super-engaging way to teach freezing point depression and phase change. Give students a large ziploc bag, a small ziploc bag, a bunch of ice, some salt, a cup of milk, 1/4 cup of sugar, and a dropper of vanilla and let them make ice cream.

Fill the small bag with the milk, sugar, and vanilla and zip it up really well. Put the baggie into the large ziploc bag and cover with ice and salt. Let partners take turns flipping the bag upside down for about 15 minutes. I always use that 15 minutes to talk about freezing point depression and relate it to the salt we use on our icy roads in the winter. Review vocabulary like phase change, freezing point, melting point, etcetera.

And, after 15 minutes, the contents of your small baggie will have turned into a pretty good vanilla ice cream – enough for a scoop each for the 2 partners.

Gamify your ice cream lab a little by turning your vocabulary review into a Q&A with rewards like chocolate syrup, maraschino cherries, and sprinkles.

Ways to modify the Ice Cream Lab

I can talk about freezing point depression until the cows come home (a little dairy humor there, did you see?), but nothing helps students understand it than to kick up your lab with some controls and variables.

Have one group try making ice cream without salt in the ice. Have another group add more salt. A third group can add more sugar to the milk. A fourth group can add less sugar to the milk.

Fair warning, though. Variations on the recipe won’t result in a delicious product so have some extra on hand for the kids who tested the variables!

What does the Ice Cream Lab fit into your curriculum?

There are a few places where the ice cream lab fits into your curriculum:

Before you teach states of matter or phase change, the Ice Cream Lab is a great way to introduce phenomenon. Why does the milk change? How does the milk change? What does the salt do? What does the sugar do?
After states of matter and phase change, the Ice Cream lab is a good activity to do while you’re doing your pre-assessment review.

I’ve just uploaded my version of the Ice Cream Lab to my TpT store if you want to check it out!

Photo credits:

Photo by Krisztina Papp on Unsplash

Amazing Animal of the Week – Cicadas 2021

2021 may be the year of the cicadas. A huge population of cicadas have been living underground since 2004 and are scheduled to emerge within the next few weeks! Cicadas 2021!

What are cicadas?

Cicadas are a group of 3000 different known insect species around the world. The oldest cicada fossils are nearly 300 million years old.

Cicadas have prominent eyes and short antennae. Their front wings are transparent and membranous. Most cicada species are active during the daytime, especially at dawn and dusk.

The largest species is the Malaysian emperor cicada with an 8 inch wingspan but most species are between 1 and 2 inches long. Most cicadas live in tropical regions and nearly all cicada species spend their whole lives in one geographic area. They do not sting, bite, or carry disease.

Cicadas are commonly eaten by birds and sometimes by squirrels, bats, wasps, and other animals which often feast at the time of emergence. Nymphs living underground may be eaten by burrowing mammals such as moles.

Cicadas are among the loudest of all insects

Cicadas are known for their loud song which they produce by vibrating drum-like structures called timbals which resemble corrugated cardboard on the abdomen of male cicadas. The vibrations of the timbals resonate within the hollow abdomen of the male cicada and amplifies the sound. A male cicada can modulate the sound by positioning their abdomen. The sound that a cicada makes can be very loud, possibly even as loud as a lawn mower or motorcycle, and can be heard up to ½ mile away. Male cicadas can temporarily disable their hearing to prevent damage when they are calling. Most cicada species call from trees. Different species may occupy the same tree and call from different heights.

Cicada life cycles

A cicada has three stages in its life cycle – eggs, nymphs, and adults.

The egg part of a cicada’s life cycle lasts 6-10 weeks. After mating, female cicadas cut slits in the bark of twigs and deposit hundreds of eggs into the twig. The adult cicadas die soon after mating. When the eggs hatch, the newly hatched nymphs drop to the ground and burrow into the ground immediately.

Nymph cicadas can not jump but have forelimbs adapted to live underground. They have strong front legs to help with digging. They excavate chambers near roots which provide sap for the nymphs to eat. They can live underground for a long period of time which varies from species to species.

When it is time to emerge, the nymphs dig an exit tunnel to the surface and climb out. Then, they molt into adults, leaving their abandoned exoskeletons on the bark of the trees they were living under. After molting, the adults rest for a day or two then spend the next 3-4 weeks mating. In some species of cicada, the males stay in one place and call to attract females, often in chorus with other males. In other cicada species, the males move from place to place, usually with quieter calls while searching for females.

Cicada broods

Different species of cicadas spend different amounts of time underground as nymphs. A brood is a population of cicadas that emerges in a geographical area at the same time and can be predicted based upon their species.

Annual cicadas spend 1-9 years underground as a nymph. A portion of the population emerges each year.
Periodical cicadas are the best known North American species of cicada. It has a 13 or 17 year life cycle. Their emergence is normally very well predicted and quite dramatic. Scientists believe that the long period in which cicadas remain underground helps the species avoid loss to predation since predators will not be able to depend upon them for food. Because so many periodical cicadas emerge at once, predators become sated quickly and later emerging cicadas are safe from predation. 2021 is the year for a cicada population called Brood X to emerge in 15 states of the eastern United States. The cicadas that will be emerging this year were born in 2004. Emergence is normally early to mid-May. An app called Cicada Safari allows observers to record when cicadas are spotted throughout the Country.

Emergence is triggered when the soil temperatures 8 inches underground reaches 64 degrees Fahrenheit. Patterns of emergence dates vary with climate and are considered a marker of climate change since records of cicada emergence date back hundreds of years.

Previous Amazing Animals of the Week:

Image credits:

Photo 1 – Photo by Shannon Potter on Unsplash

Photo 2 – This media file is either in the public domain or published under a free license, and contains no inbound file links.

Stoichiometry Basics for Middle School

In middle school, a fundamental understanding of the basics of stoichiometry can help lay the foundation for chemistry in later years. When I teach stoichiometry basics in my middle school classroom, I start with very basic chemical formulas and incremental increase the complexity as students achieve and demonstrate mastery at each level. I use task cards for reinforcement.

How many atoms are there?

Given a chemical formula, students need to be able to identify how many atoms there are of each type. For example, in H2O, there are 2 hydrogen atoms and 1 oxygen atom. I use drag and drop Google Slides task cards that break the process down into several tiers. First, I teach basic subscripts.

stoichiometry basics for middle school

The key here is to practice this skill until it is mastered before you introduce coefficients, which is the next step. stoichiometry basics for middle school

Again, the key is to practice this skill to mastery before complicating things. For some students, this may be the most advanced stoichiometry they can master at this time. For others, you can add parentheses.

stoichiometry basics for middle school

Practice until mastery and then advance your students to parentheses with coefficients.

stoichiometry basics for middle school

In all, advancing through these stages of basic stoichiometry may take your middle schoolers several days, but they they are ready for balancing equations.

Balancing Equations

Just like in basic stoichiometry, student mastery of balancing equations comes with guided practice in incremental steps. Start with a few simple synthesis or decomposition reactions with only 2 elements.

balancing equations for middle school

For some students, this may be quite challenging in middle school, depending of course on their pre-algebra skills. If your students are asking for more complicated problems, try a single replacement reaction.

balancing equations in middle school

Again, they key is mastery at each incremental step before advancing to a more complicated type of problem.

balancing equations in middle school

This is why large task card sets are so important when you’re teaching basic stoichiometry in middle school. Lots of practice leads to increased understanding and retention.

I offer several basic stoichiometry task card sets in various formats in my TpT store if you want more guidance:

Women in Science – Rachel Carson

March is Women in History Month, and Rachel Carson was certainly an impactful woman in history as well as in science. Her book Silent Spring brought awareness of environmental issues to the masses and laid the groundwork for the modern environmental movement.

women in science - rachel carson

Silent Spring was written in 1962. It warned people of the dangers of chemical pesticides, particularly DDT in agriculture, and encouraged people to question the direction of modern science. Carson accused DDT and other chemical pesticides of having lasting and detrimental effects on the bird populations and therefore the entire food web. Her book sparked controversy and the chemical industry regarded her as an alarmist, but Carson testified before Congress in 1963 about policies she felt should be implemented to protect human health and the environment. She died the next year of breast cancer.

Prior to writing Silent Spring, Carson was a marine scientist who worked for the US Fish and Wildlife Service as a writer and editor. She wrote several book about the ecosystem of the ocean including the geology of island formation, how temperature changes affect sea life, and how erosion impacts the ecosystem of the ocean.

Rachel Carson is an important woman in science because of the lasting impact of her determination to persevere in spreading the word about the dangers of pesticides. From Silent Spring sprang an entire green movement. The first Earth Day in 1970 was celebrated as a monument to the green movement and launched a traditional holiday celebrated 51 years later.

Earlier posts on Women in Science:

Rosalind Franklin

Can you help new teachers?

Do you remember your first year in the classroom?

Were you bogged down with grading, overwhelmed by prepping labs, struggling to reach those two difficult kids, confused by all the paperwork? Can you help new teachers?

can you help new teachers?

I’d love to feature your best advice for new teachers in an upcoming blog.

What was difficult for you? How did you find ways to cope? You can be as anonymous or as public as you want.

Click here to share your advice!

Thanks for your help!

~ Jay

Equinox Myths

The reason for the seasons

Do you teach seasons? It’s not normally part of my curriculum, but I always spend a day un-teaching equinox myths. There’s a lot of misunderstanding out there. Here are the things my students claim are true, until I straighten them out.

Equinox Myths:

You can balance an egg on the equinox.Well, technically, yes, you can. But not because of any weird gravity thing or whatever is going around these days. You can balance an egg every day. Don’t believe me? Try it today, and then try it again in a few weeks. Let me know what you learn.
You can balance a broom on the equinox. Again, yes you can. And, again, you can do this every day if you’re patient enough to try.
There is no shadow at noon on the equinox. I don’t know where this one came from, and it is so demonstrably false (unless you happen to be exactly on the equator at the exact moment that the sun is directly overhead) that it surprises me when it comes up every year.
The equinox is the whole day. It’s actually just a split second – the exact moment when the Sun passes over the equator.
The equinox is the day when the amount of dark equals the amount of light. This one is possibly true, depending on how you define “dark” and “light” relative to sunrise and sunset. It’s also dependent on your distance from the equator.

What equinox myths do you have to un-teach?

Amazing Animal of the Week – Gila Monsters

This week’s amazing animal of the week is the Gila Monster. Gila Monsters are black and orange lizards which grow up to almost 2 feet in length and are one of the heaviest reptiles found in the Grand Canyon, weighing in at over 5 pounds. Their skin is covered in round, bead like scales and they can live for up to 30 years.

There are over 5000 lizards in the world with up to 100 species producing venom including the monitor lizards, Mexican Bearded Lizards, iguanas, and Gila Monsters.

Unlike snakes, Gila Monsters do not inject their venom into their prey but rather the venom just flows into the bite. Humans are rarely bitten because Gila Monsters tend to be quite shy, but, if bitten, venom can cause paralysis, difficulty breathing and sometimes convulsions. No known human deaths have occurred because of a Gila Monster bite but their bites can be painful. Watch this video for more info on Gila Monster bites.

Gila Monsters are carnivores and hunt for rodents, other lizards, bird eggs, and invertebrates. They are slow and stealthy when they hunt. Their venom is mostly used for defense rather than hunting. They detect smells with a forked tongue.

Gila Monsters only live in the desert. They burrow during the hot part of the day. In the winter, they live in the burrows of desert tortoises and live off the fat they have stored in their tails.

Gila Monsters are endangered in the United States and Mexico. It is illegal to harass them, trap or capture them, hunt, shoot, wound, or kill them, or collect them.

Previous Amazing Animals of the Week:

Image: This file is licensed under the Creative Commons Attribution 4.0 International license.

How to Grade Papers Faster

If you knew how to grade papers faster, you’d be able to leave school on a Friday afternoon with an empty bag!

I’m dreaming, right? Can anyone actually do that?

I can. I haven’t graded one assignment outside of school hours in 5 years. Never. Not one.

Look, during school hours, I work hard. But after school, no, sir. That is my time.

Here’s how I get everything done during the school day:

Design your assignments to be easy to grade.

Use multiple choice questions. The standardized tests in science are mostly multiple choice questions but they’re not rote memorization questions. Design your multiple choice questions so that they test application skills. For example, “Your rover on Mars encountered an area with a lot of seismic activity but no volcanic activity. What kind of boundary is it?”
Include rubrics in your assignments so you don’t need the extra step of attaching it to the document.
Limit the length of the assignments. “Write 70-100 words to answer this question…”
Remember your job is to grade, not to edit. In science, I grade students on the quality of their answers, not on their writing ability. I may circle misspelled words or grammar, but I don’t belabor it.
Use self-grading assessments. Google Forms is amazing. Here’s a free assessment on Google Forms you can try out.

Let technology work for you.

Use Doctopus to score Google docs.
Use Google Forms for multiple choice assignments. Set them up to calculate the grade for you. When everyone is done with the assignment, open the spreadsheet and copy the grades into your grade book. Done.
Keep a file of commonly used comments. For all written assignments or lab reports, I compose a doc for myself that contains the comments I anticipate using. “Use your data to support your conclusion,” is one I use a lot! Today, I used “Tension at a normal fault causes the hanging wall to move downward compared to the foot wall” about 30 times. Then, when a student makes an error, you don’t have to type your comment all over again – just copy and paste.

Maximize your time in school.

Check your email before school, at lunch, and before you log off for the day. Leaving it open all day is an invitation to be disturbed.
Work in your classroom during your prep if you can. Better yet, close the door. I love my coworkers and I love hanging out with them. But get your work done.
Go to the copy room/mail room/main office or where ever you need to go once a day. I make a trip around the school at lunch – drop off forms, pick up mail, make my copies, whatever I need to do. If I didn’t get it done today, I’ll do it tomorrow.
Decide how long you will grade for before you take a break. I’m usually in the 20-30 minute range, then I take a 5 minute break and then go back at it until the end of the period.

Image credits:

Photo by Karolina Grabowska from Pexels

Photo by Ketut Subiyanto from Pexels

Women in Science – Rosalind Franklin

Since March is Women in History month, let’s celebrate some women in science. Rosalind Franklin was an English chemist who worked with x-ray crystallography to lay the foundation of Watson and Crick’s knowledge of the structure of DNA.

In the early 1950s, Franklin worked with Maurice Wilkins on x-ray crystallography at King’s College. X-ray crystallography is a method used by chemists to determine the three-dimensional structure of a crystallized molecule. The crystallized molecule is placed in an x-ray tube and is struck with x-rays. X-rays can pass through crystals and interact with the electrons of the atoms in the crystal which causes the x-rays to diffract or scatter. The pattern of scattered x-rays is recorded as dark marks on film and gives clues about the structure of the molecule.

In 1944, Avery, MacLeod, and McCarty isolated DNA and discovered that it contained genes that passed on genetic information, but the structure of DNA and how it worked was difficult to determine. Scientists did know that DNA was composed of nucleotides of deoxyribose, phosphates, and bases of adenine, guanine, thymine or cytosine, but how those nucleotides were arranged was still unknown. Many research scientists around the world were attempting to determine the structure of DNA but none had any success.

Franklin’s most famous photograph was taken using x-ray diffraction of DNA and is known as Photo 51. Franklin was not the first person to use x-ray diffraction on a pure fiber of DNA, but she conducted her experiments differently than previous scientists. Franklin pumped hydrogen gas through a salt solution to keep the DNA fibers surrounded by water which reveals more of the structure of the DNA. Her image was also taken after 62 hours of exposing the DNA to x-rays and revealed far more details than previously achievable.

Franklin’s Photo 51 was able to show that DNA was made of a double helix in which one twist consisted of 10 nucleotides. She also was able to show that the bases AGCT were on the inside of the helix and the phosphate groups were on the outside.

Some controversy ensued as a result of the image. Maurice Wilkins showed Franklin’s DNA image to researchers James Watson and Francis Crick without Franklin’s knowledge (see source 1). Watson and Crick went on to use the information contained in the image to develop their own model of DNA which is now the structure that we understand. Watson and Crick were also able to predict semiconservative replication, later proven by Meselson and Stahl.

Watson, Crick and Wilkins won the Nobel Prize in Physiology or Medicine in 1962 for their discoveries of the structure of DNA. Franklin died in 1958 of ovarian cancer at age 37 and the Nobel Prize is not awarded posthumously.

Image credits: Image of Rosalind Franklin is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

Sources:

https://embryo.asu.edu/pages/photograph-51-rosalind-franklin-1952

Amazing Animal of the Week – Lava Lizards!

This week’s Amazing Animal of the Week are the lava lizards of the Galapagos.

Lava lizards range in size from 2-4 inches plus tail. Males are more colorful and have a crest of spined scales running down the length of the body. Females have a cheek patch of salmon to red when they reach reproductive maturity.

Super abundant on the Galapagos, lava lizards are very territorial. They are this week’s amazing animal of the week because of a fantastic display that male lava lizards put on to ward off other males. When a male lava lizard is afraid that another male will encroach on his territory, he does a strange dance that resembles pushups. This dance makes the male appear larger and stronger and appears to be an attempt to dissuade other males from starting a fight. Intruding males might participate in a push up contest.

What do you think? Pretty amazing, right?

Lava lizards are preyed upon by hawks, snakes, and might even be cannibalized by other lava lizards.

Previous Amazing Animals of the Week:

Image of lava lizard is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license.