Author: Maddie Van Beek

I’m sure you know that we all have five senses: Taste, touch, smell, hearing, and sight. Even though the senses of taste and smell are separate, they are so close to one another that they are intertwined. Taste and smell work together to help you fully experience food. 

Activity: In the following activity, you will see why it is difficult to determine similar foods when you lose your senses of sight and smell. 



YOU WILL NEED:

• Potato
• Apple
• Knife
• An assistant
• Glass of water

Here’s what to do!

1. Peel the potato and the apple.
2. Cut a small piece of apple and a small piece of potato. Make sure they are the same shape and size. 
3. Have your assistant tie the blindfold around your head so you cannot see. Have your assistant hand you a piece of potato or apple, but do not have them tell you what it is. 
4. Hold your nose so that you cannot breathe out your nostrils and eat the first piece. Make sure you hold your nose the entire time you are chewing and swallowing. Take a drink of water to clear any remaining taste out. 
5. Hold your nose and eat the second piece. 
6. Take your guess... which was the apple and which was the potato? 
7. Part of what made this so difficult to discern the difference was that the texture of the potato and the apple are so similar. What other food items could you compare? Make sure you choose items that similar in texture AND category of taste (sweet, sour, bitter, salty). 
8. For example, you could use:
1. ketchup vs. steak sauce
2. juice vs. kool-aid
3. chocolate pudding vs. vanilla pudding
4. lime jello vs. cherry jello
5. carrot vs. broccoli stalk 

Another way you could do this is to mix water with other flavorings to represent salty, sweet, bitter, and sour. For example, you could create salt water, sugar water, lemon water, and coffee. Have your participants close their eyes and see if they can identify each drink. Record your observations. 




References: 

https://faculty.washington.edu/chudler/chtaste.html

http://www.sciencekids.co.nz/experiments/smelltaste.html

http://www.brainfacts.org/sensing-thinking-behaving/senses-and-perception/articles/2012/taste-and-smell/

http://www.innerbody.com/image/nerv12.html

Author: Maddie Van Beek

Last week, we talked about Newton’s Second Law of Motion and the week before, we talked about Newton’s First Law of Motion. If you missed these, check them out at http://discoveryexpress.weebly.com/homeblog/demonstrating-the-law-of-inertia and http://discoveryexpress.weebly.com/homeblog/newtons-second-law. 




RECAP




Newton’s First Law of Motion

An object in motion will stay in motion, or an object at rest will stay at rest, unless affected by an outside force.




Newton’s Second Law of Motion

The acceleration of an object--as produced by a net force--is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. F = m * a




Now that you have revisited Newton’s first two laws, let’s move on to our focus for today, Newton’s Third Law of Motion. 

Newton’s Third Law is concerned with forces acting in pairs. Remember, a force is a push or a pull that is enacted upon an object. Forces result from interactions between two objects. For every action force, there is a reaction force. 

Every action has an equal and opposite reaction. Every force is met with an opposing force of equal strength. For example, my coffee cup is exerting a force on my table, but my table is exerting that same force on my coffee cup. Let’s say that my coffee cup is exerting a force of 5 N (due to gravity). My coffee cup is not moving, so my table must be exerting an equal force of 5 N in the opposite direction. Because those forces are equal, my coffee cup stands still. 




Another example would be doing wall-sits. If you are sitting up against a wall, you are exerting a force on that wall. What if the wall were not exerting that same force back at you? You’d fall over! 




If you want even more information on Newton’s Third Law, check out this video from KhanAcademy: 

Practice: Click on the link below to practice identifying action/reaction pairs. 

Activity: Create your own balloon car! 




Now that you know Newton’s Third Law of Motion tells us that for every action, there is an equal and opposite reaction, you will create a visual that demonstrates that statement. You are going to be making a paper car that’s powered purely by the air of a balloon! 




Predict: How does this action/reaction pair relate to the demonstration you are about to create?

If you would like a visual demonstration of what you will be doing, watch this helpful Howcast video! 

YOU WILL NEED

• Paper
• Scissors
• Balloon
• Rubber band
• Tape
• Lifesavers
• 3 Straws
• Creativity and a sense of fun! 

Here’s what to do! 

1. Fold a standard piece paper in half, and then fold it in half again. 
2. When you open your piece of paper back up, you there should be fold lines that divide the paper into four sections. 
3. Cut down those lines so that you have four equal pieces of paper. 
4. Grab one of those pieces and two straws. 
5. Using tape, attach a straw to each of the short sides of the paper. Make sure the straws are centered so that the same amount of straw is hanging off the sheet of paper on either side. It should look something like this: 

6. The straws will be your axles. Next, you are going to add your wheels. 

7. Grab a lifesaver and put it onto the straw so the straw is going through the center hole of the candy. The lifesavers are going to be your wheels. 

8. In order to hold your wheels in place, wrap the tape around the straw on the outside of the lifesaver until it becomes thicker than the hole of the lifesaver so it won’t fall off the straw. Make sure your wheel can still spin! 

9. Repeat step 7 and 8 to create your other three wheels. 

10. Now you have the base of your car made. Use tape and your remaining paper to create walls for your car. Be creative! 

11. Now, you need a source of energy to make your car move. Put the mouth of the balloon over the one end of your remaining straw. Wrap the rubber band around the mouth of the balloon about five times. It needs to be tight enough so air cannot escape, but not so tight that it crushes the straw. To make sure the rubber band is tight enough, blow air into the straw to blow up the balloon and then place your finger over the mouth of the straw to hold the air in. Listen closely... is air escaping? If so, wrap the rubber band tighter. If not, you’re good to go! 

12. Now, you need to attach your balloon to the car. Tape the straw to the base of your car so that the balloon end is facing the front of your car and the straw end is hanging off the back. Picture your straw as an exhaust pipe. Once you secure the straw to your car, blow up the balloon by blowing into the straw and place your finger over the end of the straw to keep the air from escaping. 

13. Set your balloon car on a level surface and remove your finger from the straw. 

14. Zoom! Your balloon car is off! The air escaping the balloon is causing your car to move. For every action, there is an equal and opposite reaction.  

15. Extension: Experiment with different car designs to see how design affects the speed of your car. 



References

http://science.howstuffworks.com/innovation/scientific-experiments/newton-law-of-motion4.htm

https://www.khanacademy.org/science/physics/forces-newtons-laws/newtons-laws-of-motion/v/newton-s-third-law-of-motion

https://www.youtube.com/watch?v=5eirTBW0rpI

http://www.physicsclassroom.com/class/newtlaws/Lesson-4/Newton-s-Third-Law

Author: Maddie Van Beek


Last week, we learned about Newton’s First Law of Motion, or the Law of Inertia. You learned that an object in motion will stay in motion, or an object at rest will stay at rest, unless affected by an outside force. If you missed us last week, check out http://discoveryexpress.weebly.com/…/demonstrating-the-law-…. 




Newton’s Second Law tells us that the acceleration of an object--as produced by a net force--is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. 




What does that even mean?! 




It can be simplified into this equation:




F = m * a




F = force

- Force is measured in Newtons. 

m = mass

- Mass is measured in kilograms. 

a = acceleration 

- Acceleration is measured in meters per second squared. 







Before you try using this equation, here’s a great example from howstuffworks.com. 

Let’s say you are trying to calculate the acceleration for this dog sled. As you can see, the force is 100 newtons, and the mass is 50 kilograms. 




Before you plug the numbers into the equation, isolate acceleration, since that is what you are trying to find. 




F = m * a




Take the force divided by mass to get acceleration by itself. 




a = F/m




Next, plug the numbers into the equation. 




a = 100N/50kg




Now, divide! 




a = 2 m/s^2 




You’ve calculated the acceleration of the sled! 




But what if another dog that pulls with equal force is added to the team? 

Try calculating the acceleration this time! 




F = 200 N

m = 50 kg

a = ? 




a = F/m

a = 200 N/50 kg

a = 4m/s^2




What would have happened if you had doubled both the force and the mass? 




F = 200 N

m = 100 kg

a = ? 




a = F/m

a = 200 N/ 100 kg

a = 2m/s^2




You’d be right back to an acceleration of 2m/s^2.  




This example demonstrates how the acceleration is proportional to the force. 

The picture above illustrates the idea of net force. If two equal forces are opposing each other, the net force becomes zero. In this picture, you see that there are two dog sled teams pulling with a force of 200 N on either side of the sled, so the net force is zero. This means that the sled would not move. If the sled team on the right were bigger and were pulling with a force of 300 N, then the sled would move to the right. Make sense? 




You now have plenty of information to complete the practice equations and the activity below, but for further description of Newton’s Second Law of Motion, check out this helpful video from KhanAcademy: 

Now that you have seen a few demonstrations, let’s practice:




1. Erin and Andrew are playing tug of war. Erin is pulling to the right with a force of 100 N. Andrew is pulling to the left with a force of 200 N. What is the net force? What direction would they move? 

2. Grady is pulling a wagon that has a mass of 30 kilograms. Grady is pulling with a force of 300 N. What is the acceleration? 


3. Ashley is pushing a stroller that has a mass of 20 kilograms. The stroller is accelerating at 3 m/s^2. 
Use F = m * a to find the force. 


4. Deidre is pulling her puppy’s leash with a force of 50 N, but the puppy is pulling in the opposite direction with a force of 25 N. What is the net force? 

5. Josiah is pushing a shopping cart with a force of 75 N at a rate of 1 m/s^2. What is the mass of the shopping cart? 




Activity




YOU WILL NEED:

• 2 marbles of the same size, but different masses. Both should be lighter than the ball bearings. 
• 2 identical ball bearings
• Ramp (could be constructed out of poster board) 
• Tape Measure
• Scale
• Stopwatch

Here’s what to do!

1. Use the scale to determine the mass of each marble and ball bearing. Record these masses in your observation journal. 
2. Use a tape measure to create two meter-long ramps. You could use heavy poster board to make the ramp. Make sure you fold up the sides so the marble won’t roll off. 
3. Place one end of the first ramp on top of a stack of books to create an approximately 10 degree incline. 
4. Mark the first ramp at 30cm and 60cm. 
5. Place the end of the second ramp at the bottom of the incline of the first ramp. Make sure the marble will be able to roll smoothly from one ramp to the next. You could place a piece of tape to connect the two ramps and make sure it’s a smooth transition. 
6. Now that you’ve made your ramp, place one ball bearing at the base of the first ramp, right where the second ramp starts. Here is what your final set-up should look like: 

1. Place the marble with the smallest mass at the top of your ramp. What do you think will happen when it hits the ball bearing? Try it out! 
2. As you can see, the ball bearing moves when it is struck by the marble. Think back to Newton’s First Law, an object at rest stays at rest until enacted upon by an outside force. 
3. Try this again, except this time, use the stopwatch to time how long it takes the marble to travel from the top of the ramp to the ball bearing at the bottom of the ramp. 
4. Do this three times and then calculate the average time. 
5. Repeat step 8 and 9 with first the second marble and then the ball bearing. 
6. Next, repeat step 8-10, except start at the 30cm mark. 
7. Last, repeat steps 8-10, except start at the 60cm mark. 

Record your data and calculate the acceleration in this chart: 
 

To calculate acceleration, subtract the ball’s initial speed (zero) from its final speed and divide by the time it took to hit the target ball. 




Example: 

Speed:          100cm/2sec

Simplified:      50cm/sec

Acceleration:  (50cm/sec - 0cm/sec) / 2 sec

                      25cm/sec^2




Part 2

What’s happening when the first ball hits the second ball? 

So now that you’ve determined acceleration for each impact ball, let’s focus on what happens when each ball hits the target ball bearing at the bottom of the first ramp. As you have seen, the force of the accelerating ball causes the once-stationary target ball to move. 




How do you think the mass of the impact ball affects the time it takes the target ball to travel down the second 1m ramp once it is struck? 




Let’s find out! 




1. Just as you did before, start with the lightest marble at the top of the ramp. This time, you are using the stopwatch to measure the time it takes the target ball to travel from its starting point to the end of the second 1m ramp. You will start the stopwatch once the target ball is struck and stop the stopwatch once it reaches the 1m mark. 


2. Repeat step 1 three times and record the average time. 


3. Repeat steps 1-2 with the second marble. 


4. Repeat steps 1-2 with the other ball bearing. 


5. Record in the table below: 

Record your observations. Did the mass of the impact ball affect the average time the target ball took to travel 1m? Why do you think this is? 

You should have found that the more mass the impact ball had, the faster the target ball rolled 1 meter. This explains Newton’s Second Law: Larger mass means larger force, which then means larger acceleration. This demonstrates how the variables of mass, acceleration, and force are proportional with one another. 




Extension: 

Now that you have the mass and the acceleration of the impact balls from part one, you can calculate the force with which they hit the target ball bearing. Remember, the force is found by multiplying the mass and the acceleration. 

References

http://science.howstuffworks.com/innovation/scientific-experiments/newton-law-of-motion3.htm

http://www.physicsclassroom.com/class/newtlaws/Lesson-3/Newton-s-Second-Law

http://swift.sonoma.edu/education/newton/newton_2/html/Newton2.html

http://www.physicsclassroom.com/class/1DKin/Lesson-1/Acceleration

Author: Maddie Van Beek

Today we are going to be learning about Newton’s First Law! Physicist Sir Isaac Newton came up with the three laws of motion. The basis of the first law is:

An object at rest stays at rest 


AND 


An object in motion stays in motion 


UNLESS


Acted upon by outside sources. 

This is often called the law of inertia.  Inertia is defined as a tendency to remain unchanged, and continue in its existing state of rest or uniform motion unless changed by an external force. Basically, this means that objects will keep on doing what they’re doing unless an outside force affects their state of motion. 

Can you think of this happening in the real world? I can! For example, I take coffee to my job with me every day. When set my coffee mug in my cup-holder in my car, the coffee in the mug is at rest. When I accelerate out of my driveway, the car goes from being in rest to being in motion. But there is no force acting on the coffee in my mug, so it wants to stay at rest. Consequently, the mug moves forward along with the car, and the coffee sloshes out of the mug. 


To learn more about Newton’s Laws, check out the link below! 

Today, we are going to focus on the first part of the law: An object at rest stays at rest.


The video below will demonstrate our focus today. 

Reflect:

• What happened in this demonstration? 
• How was Newton’s First Law at work here? 
  

Want to try this out on your own? 

YOU WILL NEED:

• Crochet hoop
• Pen cap (or other small object)
• Bottle or vase
• Water

Here’s what to do! 

1. Fill the bottle with water. 
2. Place the crochet hoop on top of the bottle’s opening. 
3. Carefully place the pen cap on top of the crochet hoop so that it is balanced directly over the mouth of the bottle. 
4. Use one finger to quickly pull the crochet hoop directly sideways. 
5. When this happens, the pen cap should fall straight down into the bottle. 
6. If this didn’t work for you on the first try, don’t get frustrated! Just try it out again. If you continue to have difficulties, try using a bottle with a wider mouth. 

Here’s another way to demonstrate the same concept. These students used a paper plate, a toilet paper roll, and a glass instead of the crochet hoop and bottle. 

In the following video, two students came up with different way to demonstrate Newton’s First Law. 

Want to try out this method? 


YOU WILL NEED: 

• Two identical bottles
• Water
• A dollar bill 

Here’s what to do!

1. Fill one bottle with water. 
2. Place the dollar bill over the mouth of the bottle with water in it. 
3. Balance the second bottle over the first bottle with the dollar bill in between the mouths of the bottles. 
4. While carefully keeping the mouths of the bottles aligned, flip them over and carefully set them down so that the bottle with the liquid is on top. 
5. Now, grab the end of the dollar bill and quickly pull it out! 
6. What happens? The two bottles are stationary and the liquid from the top bottle falls into the bottom bottle. 

Reflect: How did this demonstration show you Newton’s First Law? What were some similarities between this demonstration and the first one you watched? Differences? 




These were just two ways to demonstrate Newton’s First Law at work. What other ways can you think of to demonstrate Newton’s First Law? Brainstorm some ideas and try them out! We’d love to hear about them! 




References: 

• http://www.scholastic.com/teachers/article/40-cool-science-experiments-web
• <iframe width="420" height="315" src="https://www.youtube.com/embed/uOSBC0SXVR4" frameborder="0" allowfullscreen></iframe>
• <iframe width="420" height="315" src="https://www.youtube.com/embed/5k2hhEFNxdM" frameborder="0" allowfullscreen></iframe>
• http://www.physicsclassroom.com/class/newtlaws/Lesson-1/Newton-s-First-Law

Author: Maddie Van Beek



Have you ever heard that you can tell how old a tree was by counting the rings on its stump? The bummer about this method is the tree has to die before you can tell how old it is! Turns out, there is a way to estimate tree age while the tree is still alive. 



Keep in mind, this method provides an estimate. This means the number you discover may not be the exact answer for how old the tree is, but it does get pretty close! 



Today, you will get to learn how to estimate tree age, try it out in real life, and practice your measuring and multiplication skills at the same time. 



Before you do this on your own, let’s practice. 



The first thing you will do is find the diameter (in inches) of your tree. Remember, you find diameter by dividing circumference by pi, or 3.14. So really, the first measurement you must make is the circumference of the tree. Since we’re not outside yet, let’s just try an example.  



As a reminder, the circumference is the distance around a circle. 



The circumference of your tree is 52 inches. 



Finding diameter: 



Circumference / pi = Diameter 



52 in / 3.14 = 16.56 in



Now that you have your diameter, you will multiply that number by the growth factor. 



Click the link below to find the growth factor chart. The reason we need the growth factor chart is because not all trees grow at the same rate. This chart will help you find a more accurate estimation of the tree’s age based on the type of tree and it’s growth factor. 

If your tree is a silver maple, the growth factor is 3. 



Growth factor equation: 



Diameter x Growth factor = Tree age



16.56 in x 3 = 49.59



Based on the equations, the tree I measured is almost 50 years old! 



Before you go outside and start measuring, choose three other trees on the Growth Factor Chart and practice the equations that we just did. 



Now you are actually going to go outside and start measuring. Of course, not all of us are tree experts! If you are unsure about how to identify different types of trees, check out the link below to help you out. 

YOU WILL NEED:

• Trees
• Measuring tape
• Growth factor chart
• Pen
• Paper

Here’s what to do! 

1. Print out the growth factor chart. 
2. Bring the chart and measuring tape outside with you. 
3. Find a tree that you want to measure. 
4. Identify the type of tree. If you are unsure, make your best guess! Remember, you can always go back and check your handbook. 
5. Before measuring, predict how old you think this tree is. 
6. Wrap the measuring tape around the trunk of the tree. Make sure it is pulled tight so your measurement is accurate. 
7. Write down your measurement (circumference) and then find the diameter of your tree using the equation from the example. 
8. Next, find the type of tree on the Growth Factor Chart to determine the growth factor for your tree. 
9. Use the Growth Factor equation from the example to determine the age of your tree.
10. Compare your predictions with your findings. Were you close? As you continue measuring trees, are your predictions closer to your actual findings? 

Extension: Plot a map of the trees in your area and create a legend for how old the trees are. You could color code the trees based on their ages. You might find that some areas have significantly older trees or some areas that have mostly younger trees. After completing the map, analyze why some areas would have older trees than others.  



References:

http://www.education.com/activity/article/How_Old_Are_They/

http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree