3rd-5th Grade Session 3: Table Tennis Science!

This week we took a deeper look at the variables that make for a perfect serve and return hit in the game of table tennis.  To start out we first discussed those variables that are hard to control and those variables that we can control.  We defined those variables we can control as the independent factors in the experiment. Then each group came up with a working definition of what a perfect serve is so that we could have a point of reference when observing and analyzing the hit.  Once everyone defined "the perfect hit", we decided to test how the mass of the ball, an independent variable, affects the perfect hit.  To test this idea we used three types of balls: 1) a plush small basketball, 2) a plush baseball, and 3) a ping-pong ball.  Each group measured the mass of the balls using a scale as well as an electronic scale.  Before measuring the masses, we we went over how the triple scale is used.

After weighing the balls it was time to test out the idea!  After getting familiar with how the game is played, the trials began.  For each ball, students conducted four trials - two underhand hits and two overhead hits and recorded their results on a data table.  When  all the data was collected, the young scientists analyzed their data and looked for patterns and concluded that the heavier the ball is the harder it is to have a perfect hit.  We also discussed how in any sport where human power is involved the key to a "great" athlete is also learning how to control those muscles that make for a great "play" and thus is all about practice, practice, practice!

K-2nd Grade Session 3: Skittle Chromatography!

This week our young chemists used chromatography to study the colors that are used to make Skittles flavorful shells.  We first talked about what chromatography is and how chemists use it to learn about the make up of chemicals and answer questions about our world. Then we made predictions about what skittle colors would become visible after conducting the experiment.  We then got busy with the experiment!  As the liquid began to be absorbed by the filter paper we talked about how this "absorbing" is called capillary action and how it is exactly the same process that happens in our bodies as the blood from our legs "moves" up back to the heart (just a tidbit of biochemistry). All in all, our young chemists were able to connect how chemistry is related to our everyday life - even candy-making takes some chemistry action!

3rd - 5th Grade Session 2: Field Goal! The Science Behind a Perfect Football Kick

In this session our scientists studied the science of projectile motion and it's applications to kicking a football. First we discussed how projectile motion is involved in throwing, kicking, and punting a football and how professional players such as quarterbacks and kickers need to have a good understanding of how a football moves through the air in order to help them win games.  We then talked about what factors affect a kick such as distance from goalposts, wind, and amount of force/energy used when kicking the football.

We focused on distance in particular for this experiment.  The question that was raised was: How does changing the distance from the goalposts affect the accuracy of a field goal kick?  After reviewing what a hypothesis is (an educated guess) students discussed what their hypothesis was for this experiment.  Some students thought that increasing the distance would not matter, being that the main factor could be weather conditions.  Other students thought by decreasing the distance then the kicker would have a better chance of scoring a field goal.  In this particular experiment, a constructed sling shot represented the kicker, a meter stick was used to represent the football field (students measured distances in centimeters instead of inches), and two rulers attached to two cups represented the goalposts.

The first part of the experiment was to build the sling shot.  Students had to work together in pairs to construct a sling shot with the given materials and tools.  This part of the experiment required some engineering!

After the sling shots were constructed, the students set up the rest of the experiment and began to test their hypothesis by shooting a ball using the sling shot from different distances and recording their observations on a data table.  As a safety precaution all scientists wore goggles.

After testing out their hypotheses, students got busy analyzing their data by computing the field goal percentages for each "kick" from the different distances.  The percentages were calculated by using the following formula: (Math to the rescue!)

Field Goal Percentage = Number of successful field goals x 100

                                      Number of field goal attempts

With their partners, our young scientists made some conclusions based on their analysis.  In most cases, students observed that the less distance between the "kick" and the goalposts the more likely a "field goal" was made.  In some cases, students observed that the way the sling shot was constructed made a huge difference in terms of the force/energy used for the "kick" thus affecting the accuracy of the kick.

I then asked the scientists to think about something that they would change if they were going to do this experiment again. Some suggested we would get more accurate results if the wind factor was involved. Others thought their sling shots could have more improvements in their design.

We closed with going back to how professional football kickers and punters use math and science to achieve the best kick and how the human factor (being human) makes a difference in terms of achieving a successful kick.

K-2nd Grade Session 2 - States of Matter: Which liquid is heavier (has more mass) Alcohol or Water?

This week our young chemists learned about states of matter and how some liquids are heavier than others even if they look the same!  We began by talking about the three states of matter.  In particular we talked about how the tiny stuff that makes up matter are called molecules and how the way they are organized is what makes something a solid, a liquid, or a gas.  First we looked at what the molecules look like in each state:

To help them understand this concept we played a game in which students had to pretend they were all molecules and had to become a solid, a liquid, and then a gas.  They did a great job collaborating and discussing their ideas.  Their models were fantastic!  For a solid they all hugged and huddled up together in a tight "ball".  For a liquid they held hands, but only pinkies.  To demonstrate a gas they all separated and some jumped, others walked around each other, some even bumped heads to demonstrate how gas molecules are in constant motion!

Once everyone had a firm grasp for what each state of matter looks like we then talked about liquids in particular. Can one liquid be heavier than another? How could we test the idea? I explained that we would test out the idea by comparing two liquids that look very much alike: rubbing alcohol and water.  To do so, the young students used a constructed scale using cups, a ruler, and a pencil (had to throw in some engineering!) and 2 paper bag strips dipped in alcohol and water respectively.  The idea is that the ruler would tip over to the heavier side.  We discussed why the ruler tipping to one side could signify that one liquid was heavier than the other.  Students predicted that one liquid would begin to dry up faster than the other.  We talked about what "drying up" means and our chemists said that it meant "the molecules would separate" and become "a gas."  These young chemists are quite inquisitive and observant!  The students shared their predictions about which liquid - water or alcohol, would "dry up" first.  Here they are setting up the experiment.

While we waited for the liquids to "dry up", we conducted a demonstration to see if it would give us yet another clue as to what liquid was heavier.  To do so, I set up a beaker with green (food coloring) water to boil, then filled a cup with alcohol and put a couple of red food coloring drops.  I asked the students to predict what would happen if I poured the red alcohol into the green boiling water.  Some students thought that an explosion would take place so we all put on goggles to be safe.  Before pouring in the red alcohol into the green water we talked about colors and what color is made when you mix red and green, students thought that a dark color would appear.  We went ahead a mixed it, to their surprise nothing blew up and the red alcohol went to the top of the beaker where it would disappear.

I asked our chemists to share with a friend why they thought the red alcohol was not mixing with the green water.  Some students thought that perhaps alcohol was "lighter" than water, others were wondering where the alcohol went since it was leaving the top as well?  We then talked about liquids and gases once again and how perhaps alcohol is not as heavy as water because it becomes a gas faster.  We went back to check on our constructed scale experiment to check if indeed our predictions were correct or not.  Below are some pictures of what students saw:

Students made the observation that the paper strip that had the alcohol was completely dry while the strip that had the water was still a little wet.  Students also noted that the side that had the strip with alcohol was dipped while the side that had the strip with water was higher.  Based on their observations our young chemists concluded that although water and alcohol look the same, alcohol is actually a "heavier" liquid.

3rd-5th Session 1 - Basketball: How much energy does dribbling take?

During the next six weeks, these scientists will be studying, manipulating, and understanding the science behind sports.

On our first session we talked about how understanding the science behind sports can actually improve our game and make us better athletes.  We then looked at basketball in particular and what dribbling is all about. To understand what is happening and how energy is transferred between the ball and the surface it is bounced off, we performed an experiment in which the scientists had to bounce the b-ball off three different types of surfaces.  Each time, the height of the ball was measured in centimeters to see how much energy "stayed" on the ball with each bounce.  To help us take more accurate measurements we recorded each trial and used painter's tape to make 20cm markings on the wall/meter stick.  The three surfaces used were carpet, wood, and cement.

After collecting our data and making observations we talked about our findings. Scientists noticed how more energy seemed to stay on the basketball on the harder surfaces, especially concrete.  This was noticed on how many centimeters the ball bounced back up after being originally dropped off from 100cm off the ground.  We then talked about what surface is actually used to play basketball - wood, and why is it not played on concrete being that the best return bounce seems to be off concrete.  Some conclusions that these scientists came up with is that maybe we don't want the ball to keep too much energy because then it would be harder to control the ball as you dribble down the court.  We concluded by talking about the force of gravity and how that is the force that drives all objects, including us humans to stay put on the Earth.

Pssst, they don't know they are becoming physicists ; )