real science for today's homeschooler

Using Popcorn to Practice Scientific Method

Using Popcorn to Practice Scientific Method

This is a fairly common science fair project that I actually helped my grandson carry out for an elementary science fair. It’s definitely not a new idea, but a great way to let children work through the scientific method using a fun topic . . . POPCORN! The question to be answered is: “Does storage temperature affect how well popcorn pops?” Children will be storing popcorn in a warm environment, room temperature, cold, and frozen. Before beginning the experiment, encourage students to make a Hypothesis. Ask them to decide which storage method they think will work best, and why.

Materials: large bag of loose popcorn (not the individual “flavored” bags), baggies, paper lunch sacks, access to a microwave

Here’s the procedure we used, but it’s important to let your child come up with the procedure if this is to be a scientific method experiment.

1. Put 100 popcorn kernels in a plastic baggie and label as “warm.” Repeat with 3 more baggies, labeling them as “room temperature,” “cold,” “frozen.”

2. Place the baggies in the appropriate area. For example, store the “warm” bag under an electric blanket, the “room temperature” bag in the pantry, the “cold” bag in the refrigerator, and the “frozen” bag in the freezer. Select a specific time for storage, such as a week, a month, etc.

3. After the storage time is complete, remove the bags from their storage area at the same time. To test the storage methods, divide out the 100 popcorn kernels between 5 paper lunch sacks, with 20 kernels in each bag. Label each paper sack with the appropriate storage method. Repeat with all the remaining popcorn, being sure to label each paper sack with the correct storage method!

4. Decide on a specific popping time. Somewhere around 2 minutes works best, but any time will work if it gives the popcorn time to pop and you keep the time the same for all trials.

5. Put one of each sack of popcorn into the microwave at the same time. (In other words, place one sack that contains popcorn stored as “warm,” one sack with “cold” popcorn, etc. Turn on the microwave for the specified time. After the time has elapsed, remove the bags and count the number of kernels that popped. Record. Repeat until all the popcorn has been tried.

Data: Here’s a sample data table that can be used to record the results. For older children you may want to let them design their own table.

  Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average
warm            
room            
cold            
frozen            

 

Older children can find the average of each type. For younger children who may not understand the concept of averaging, change to “Total” for the last column.

Analysis: Younger children can compare the totals to see which storage method resulted in more popped kernels. Older children can graph the results for a visual representation.

Conclusion: Have students state out loud, or write down, which storage method produced the most popped popcorn. Why do they think this method worked best? Also have them refer back to their original hypothesis. Was their hypothesis right or wrong?

HINT: Based on experience, don’t try to pop one bag at a time in the microwave. There will not be enough water in the popcorn to absorb the microwaves and the appliance will overheat! Mine actually stopped working for awhile! Popping four bags at a time worked well for us, but do feel the sides of the microwave after the first round to make sure it isn’t overheating. Take breaks between rounds if needed.

ALTERNATE METHODS: Children can also come up with their own idea of what to test, such as light vs dark, storage time, type of storage container, etc. The more children are able to make the experiment their own, the better!

BACKGROUND: Depending on the age of your child, You may also want to have them research WHY popcorn pops. Here’s a great website that explains the science of popcorn, as well as some interesting history: http://www.popcorn.org/Facts-Fun/What-Makes-Popcorn-Pop.

Share this on...Email this to someoneTweet about this on TwitterShare on Facebook

Separating a Mixture

Separating a Mixture

A mixture contains two or more substances that are not chemically combined. Each substance retains its original properties, and can be separated by physical means. Challenge your student to design a method to separate a mixture into its separate components.

First, you’ll need to make the mixture that will be separated. A suggestion would be to mix salt, sand, pebbles, and iron filings. Home improvement stores sell “play sand” which works well for many science experiments, and you can order iron filings from the internet. The base of your mixture should be sand, then add the other substances in slightly smaller quantities.

Here are the steps of the experiment:

1. Have your child observe the mixture and guess the substances from which it is made.

2. Explain the scientific definition of a mixture and give your child a sample of each of the individual substances in the mixture.

3. Ask your child to brainstorm the physical properties of each of the individual substances. (If they don’t come up with these on their own, lead them to include that salt dissolves in water, pebbles are much larger than the other ingredients, and iron is magnetic.)

4. Ask your child to brainstorm how the physical properties of the substances could be used to separate each from the mixture. Depending on the age of the child, you may or may not have to help with this step. You can also lead them to experiment with the individual substances by seeing which will dissolve in water and which are attracted to a magnet, etc.

5. Once your child has developed a plan to separate the mixture, help them carry it out. Here are a few suggestions to successfully separate the four ingredients:

PEBBLES – Separate the pebbles either by picking them out individually with tweezers or fingers, or by straining them out. A colander or a piece of window screen works well as a strainer.

IRON FILINGS – The small iron fragments can easily be pulled from the mixture with a magnet. To keep the magnet clean, put it inside a plastic baggie. After you have collected the iron filings on the outside of the bag, pull the magnet away from the plastic and the filings will be released.

SALT – Pour the mixture into a container of water and stir well until the salt has had time to dissolve completely. Pour off the water. To demonstrate that the procedure worked, evaporate the water to reveal the salt left behind.

SAND – Once the other three ingredients have been removed, the (wet) sand will be left behind.

6. Emphasis that your child has proven that the original material was a mixture because the individual parts were separated by physical means.

Share this on...Email this to someoneTweet about this on TwitterShare on Facebook

Measuring Volume

Measuring Volume

Many science activities rely on taking an accurate measurement of the volume of liquids and solids. Below you’ll find a reference for how to measure the volume of different types of matter. Activities in this blog that require students to measure volume will include a link back to this page for reference.

VOLUME OF A LIQUID

This one is easy . . . add the liquid to a container that measures volume! 🙂 One suggestion would be to find measuring containers that measure in milliliters (mL)and (L) so that children become familiar with metric measurements.

VOLUME OF A REGULAR SOLID

A “regular” solid means one that has a specific geometric shape whose dimensions can be measured accurately with a ruler. Here are some of the basic formulas used to measure the volume of geometric shapes:

formulasBe sure to measure lengths in metric units such as centimeters (cm) or millimeters (mm). All volume measurements will then be in cubic centimeters  or cubic millimeters.

VOLUME OF AN IRREGULAR SOLID

The water displacement method is typically used to measure the volume of an “irregular solid,” a solid that lacks a regular geometric shape whose dimensions can be measured with a ruler. To use the water displacement method you will need a container that will hold the object to be measured, and that is marked in metric units, preferably milliliters.

1. Fill the container with enough water to cover the object.

2. Record the amount of water in the container, preferably in milliliters.

3. Insert the object to be measured, being careful not to let it “plop” in and splash water out!

4. Record the new water level in the container.

5. Subtract the two water levels to determine the amount of water that was “displaced” (moved out of the way) when the solid object was inserted.

6. Because 1 milliliter of water = 1 cubic centimeter of water, you can assume that the volume of water displaced in milliliters is the same as the volume of the solid object in cubic centimeters.

Many of the activities in this blog will require that students find the volume of different substances. This page will be linked so you can easily return for a refresher on measuring volume! 🙂

 

Share this on...Email this to someoneTweet about this on TwitterShare on Facebook

Periodic Table Basics

Periodic Table Basics

If your child has already learned about the parts of an atom (proton, neutron, and electron) they can understand the basics of the periodic table. From a basic periodic table, a young student can find: 1) the abbreviation for the element’s name, 2) how many protons an atom of the element has, 3) how many neutrons an average atom of the element has, 4) the number of electrons a neutral atom of the element has. Use the information below to teach your child the basics of using the periodic table. Then, turn the Periodic Table into a game. Give “clues” to a particular element and have your child use the clues to identify the element. You’ll find few examples of element clues at the end of this post to get you started.

Here’s an overview of periodic table basics:

periodic tableThe one or two letter symbol in each box is an abbreviation for the name of the element. In the example on the right, the abbreviation for carbon is C.

The number that is always above the symbol is the atomic number of the element. The atomic number gives the number of protons in one atom of that element.

The number under the symbol is the atomic mass. It is the average number of protons plus neutrons found in one atom of the element. You can use that number to find the number of neutrons in an average atom. Just subtract the number of protons from the rounded atomic number and you will have the average number of neutrons in one atom of the element.

Finally, in a neutral atom the number of electrons is always the same as the number of protons. So, the atomic number also gives the number of electrons in a neutral atom of the element.

Element clues:

1. Which element has 80 protons?

2. Which element has 16 neutrons and 16 electrons?

3. Which element’s name is abbreviated Fe?

Continue using the periodic table to make clues as long as the game holds the student’s interest. The more they become familiar with the periodic table now, the less intimidating it will be in upper level science classes!

Share this on...Email this to someoneTweet about this on TwitterShare on Facebook