Preflight

lecture preflight 05
1: Ice floats because water becomes less dense as a solid. The ice is less dense than the liquid water so it floats.
2: The weight of rock being removed from the boat allows the buoyant force to push the boat upward more. By placing the rock into the pool, the rock displaces a small amount of water but the boat displaces much less with the removal of the weight. The rock's mass was taking up more surface area power on the water in the boat than out of the boat which makes the water level lower.
3: I love the experiments and I feel it is fine!
4: I cannot think of one for this week. I am sorry.

lecture preflight 05
1: It is less dense than water.
2: The boat now has a smaller mass and is therefore displacing less water than it was before causing the water level to drop.
3: I don't think it had anything to do with your lecture at all... they are always fun and interesting! I think that we were just tired. There was a lot of catching up to do last week in all of our classes because of the snow day.
4: Black holes... what are they?

lecture preflight 05
1: Well anything that floats is less dense than water or whatever it's floating in. Ice is lighter that water.
2: I think because when the rock was in the boat, the boat was heavier. The boat has a larger surface area than just the rock, so when it was in the boat, the water was being pushed by the wide boat, making it rise up. But once the rock is thrown out of the boat, the surface area of the boat isnt weighed down as much and pushes the water less. This means the water level would get a little lower.
3: Hmm... i'm not really sure what to do to change lecture. I like the survery questions and demonstrations!
4: I learned before that icebergs are huge underneath the water, and the part we see above the water is pretty small (comparitively). How does that work?

lecture preflight 05
1: ice floats because it is less dense than water. It is less dense because when water freezes it expands slightly, which means that the same amount of mass takes up more space. Hence one gram of ice would weigh less than one gram of water.
2: As you took weight off off the boat, the boat displaced less water, hence the level of water was lower.
3: maybe spend less time on each specific topic or demonstration so that we can cover a wider variety of things
4: what makes a rainbow happen?

lecture preflight 05
1: ice floats because the density of it is not greater than water.
2: water spilled out of the pool
3: I honestly think that all the lectures have been interesting. I think Wednesday's lecture may been a bit muted because around the time of lecture students are tired.
4: I can't think of any at this moment.

lecture preflight 05
1: Water in its frozen state is less dense than water in its solid state
2: More weight at the top of the pool (i.e. in the boat) displaces more water than a some weight at the top of the pool and some weight at the bottom of the pool (i.e. the rock)
3: Everything is going great!
4: Why do windows have consensation on them in the winter?

lecture preflight 05
1: Its density is less than one.
2: Well the boat floated even with the rock, now that the rock sank it displaced some of the water.
3: I believe the weather has a lot to do with it.
4: I was driving home from Indiana and all of a sudden the freezing rain turned into snow. Why the sudden change?

lecture preflight 05
1: Its density is less than 1.
2: The displacement of the rock when it was in the boat was distributed over the entire boat; when it was in the water, it had to stand for itself and therefore made a difference.
3: I think that was a particularly hard class to go to because it was the first time we'd had that class in 2 weeks. Also, I don't feel like there were as many questions asked and therefore we didn't have to answer them...
4: Why do vocal chords get tired after repeated use?

lecture preflight 05
1: Ice floats because, although it is still water, the volume of the water has increased and the mass stays the same. This makes the density less that one.
2: The water level is lower because your boat is less submerged into the water because you lost weight in the boat. Therefore, the boat is pushing outward less onto the water and allowed the water level to become lower.
3: I don't have any suggestions for class. I thought it was very interesting and useful.
4: Right next to my dorm they just put in "UIUC's first rain garden". What is a rain garden? Is there a point to it?

lecture preflight 05
1: because it is more dense than the water.
2: since the rock was taken out of the boat the boat, the rock was applying a force to the boat causing it to float lower than it would without the rock. When the rock was dropped the boat floated higher in the water, so the water level raises.
3: cookies?
4: Does a person's diet affect hair growth?

lecture preflight 05
1: Because it is less dense than water.
2: Your boat is not as heavy without the rock so it rises a little bit and looks like there is less water.
3: Prizes and cookies!
4: Why does alcohol not freeze

lecture preflight 05
1: Ice floats becasue its density is less than that of water.
2: The density of the rock is obviously higher than the density of the water, so becasue of the rock's higher density, some of the water was literally pushed out of the swimming pool.
3: Perhaps more hands on experiments/demonstrations where students can come down, volunteer and help you.
4: Why can certain fish/sea creatures only survive in salt water and others can only survive in fresh water, and some both?

lecture preflight 05
1: Because water in its frozen state, ice, is less dense than when it is a liquid. Why this is, I do not know. But by observation, I can conclude that.
2: Because the boat is now lighter without the rock in it, the force from the water pushing on the boat to make it float is now less (less energy/work). Therefore, the level of the water is lower. (?)
3: I find Wednesday lecture to be my most interesting and fun class of the week. I don't know why others wouldn't want to participate/attend. I think that the time that lecture is held, so late in the afternoon, has much to do with the lack of participation, not the lecture itself.
4: I would like to know in more detail the physics of cruise ships. They are absolutely huge, why don't they sink?

lecture preflight 05
1: Ice floats because it's density is less then the density of water.
2: Maybe when you dropped the rock into the water the rock caused water to become displaced out of the pool. Which would cause the water level to go down.
3: I cant really come up with any suggestions, sorry!
4: Why do birds sing?

lecture preflight 05
1: Ice floats because it has a lower density than water.
2: The water is lower because the boat does not weigh as much anymore so it is not pushing down on the water as much. When the boat pushes down on the water, the water is higher, but when the boat does not push on it as much, the water will lower.
3: I was there and it was a little quieter than normal. For me, I know I was just tired and it was a long day. But to make the class a little better, maybe have more experiments that have a greater appeal, not just watching a motor or fan move.
4: How deep is the deepest part of the ocean?

lecture preflight 05
1: b/c it is less dence than liq H2O
2: It just seems lower
3: I like lecture just the way it is, the dems are fun!
4: would pop ice cubes float?

lecture preflight 05
1: Since some ice has air pockets/bubbles maybe that makes the density lighter than 1 g/ml like water, therefore it would float.
2: Maybe because there is less weight in the boat so it makes the water level decrease
3: I enjoy sitting in lectures because I find the experiments very interesting. Maybe it was just an off day for the class because I wouldn't change anything
4: How do you get a piece of paper from a tree?

lecture preflight 05
1: It is less dense than water
2: It just looks that way because now the boat is floating higher.
3: You may be able to take wagers and give a reward if someone can explain what will happen before it does. OR write guesses down on a piece of paper with name.
4: Why does the color of a shirt change when you wash it with other colors? Is there a way to prevent this from happening?

lecture preflight 05
1: It has less density.
2: The rock must have weighed a lot. The rock pulled the boat down, therefore having a larger portion of the boat submerged and using up a larger volume than the rock itself. The amount of volume the boat took up with the rock subtracted from the amount of volume without the rock is a larger volume than the rock itself, therefore making the water level go down.
3: Have students participate in activities more.
4: How does a submarine submerge itself underwater?

lecture preflight 05
1: Ice floats because the atoms in ice are closer together, therefore giving it the same weight as water but less volume (or space taken up). Which would make the density of the ice less than the density of water and therefore the ice would float.
2: The level of the water in the pool gets lower because when you drop the rock into the water the boat will then float up higher on the water therefore not taking up as much volume in the water.
3: I know that it may be hard to get volunteers sometimes, but trust me we are all very interested. A few of us were discussing that this past week actually, that your lecture is one of the few lectures of ours that we don't have to take notes in yet we are paying attention/interested in the most (and actually understanding what you're teaching!).
4: I have a touch lamp on my desk, what is it that makes the light turn on when I touch it?

lecture preflight 05
1: Ice floats because its desnsity is less thab 1 g/ml.
2: Some of the water may have spilled over the side of the swimming pool when the rock was dropped in therefore causing the volume to decrease.
3: I really don t have any suggestions I beleive that you are doing a great job :-)
4: I m still having a little trouble with Archimedes Principle. Can you give a clear cut defintion of what exactly it is?

lecture preflight 05
1: Ice floats because it has density of less than what it is floating in.
2: The rock was in your boat earlier and causing the density of the boat to increase. Therefore when you put the rock in the water, the boat is less dense and floats more (pushing into the water with less bouyant force) and therefore the level of water is lower.
3: I like watching the experiments and doing the iclicker questions. I just don't know that much about science, so when you ask questions about science I usually have no clue what to say.
4: How do icebergs relate to what we did in lab this week?

lecture preflight 05
1: Ice floats because its density is less than that of water in liquid form.
2: The level of the water in the pool is lower because the boat is lighter (has less mass) and is therefore displacing less water.
3: I thought it was fun. I just think that people don't understand if they are supposed to be writing things down, or what sort of things will be on the quiz.
4: How is it that lotion makes your skin less dry??

lecture preflight 05
1: Ice floats because it is less dense than water.
2: The boat and its contents have less mass therefore it displaces less water.
3: Honestly, just picking on random people to help with experiments would be fine :)
4: When soaps say the word, "anti-bacterial" what exactly does this mean?? If you use that particular soap you are killing off all bacteria? What is put in soap, that makes it kill germs?

lecture preflight 05
1: Because ice is less dense than water. A good way to think about this is that ice and water are the same thing, but when water freezes it takes up more room (ie. drinks freeze when you leave them in the freezer). So, the same amount of substance that takes up more space is less dense than the first that takes up less space.
2: Because when the rock was in the boat, the boat (has more surface area that touches the water) displaces more water than the rock would itself. That answer was confusing, but what i am trying to say is that a boat would displace more water from the weight of the rock than the rock would itself.
3: I like all the experiments you do. It seemed likt they were more at the end of the lecture though, so maybe move some closer to the begining too??
4: Ice is less dense than water, but how does that compare to snow? I heard that every 10 inches of snow equal 2 inches of water.

lecture preflight 05
1: Ice has a lower density than water.
2: When the rock was taken out of the boat, it was less dense and therefore it rose.
3: Its interesting.
4: The pressure underwater. For example, if you were in a car underwater, would you be able to open the door or not?

lecture preflight 05
1: Ice floats because its density is less than 1 g/mL. (it's actually about 9% less dense than water)
2: Maybe without the rock your raft is higher up in the water, so it appears as though the water level is lower? Or perhaps water splashed out of the pool when you dropped the rock.
3: Honestly I think February is just everyone's least favorite time of the year (everyone is anxiously awaiting spring)... I don't think that you are doing anything wrong.
4: How does a dryer sheet prevent static electricity?

lecture preflight 05
1: Because it is less dense then liquid water.
2: Because the rock was displacing water. The rock had volume and was taking up space. When that rock was gone, the water could reced.
3: You have a great class. I think it's just getting really busy for everyone these next few weeks before spring break and people are getting run down.
4: How bad are tanning beds for you and why?

lecture preflight 05
1: Water expands when it freezes, making ice less dense than water. Objects that are less dense float to the top, so the ice floats.
2: The rock is more dense than the water, causing it to sink in the first place. However, this also means that when the rock is in the bottom of the pool, it only displaces an amount of water equal to its value. When the rock was in the boat, the boat is a larger object, and the rock causes it to sink, displacing more water than the rock itself.
3: Personally, I have taken a lot of physics already in high school and in college, including 140, 211, 212, and 214. But I still find the lecture to be interesting. The material for me is very easy, but I enjoy how you explain it and I have learned the answers to some basic questions.
4: While chaotic effects in the universe prevail, there must be a state of maximum chaos. What happens if that point is reached?

lecture preflight 05
1: Ice has a density that is less than water--less than 1 g/mL--which is why it floats in water.
2: The water level appears to be lower because the boat has risen in the water. The boat is floating higher in the water because it is less dense (it has less weight in the boat without the big rock at the bottom of the boat) .
3: No big suggestions, just keep doing experiements and using the iClickers!
4: If some liquids cannot mix because of different densities (like water and oil) then how do they mix when we bake something or make a mixture (like brownie or cake mix)? How does differing densities effect mixing and cooking and baking?

lecture preflight 05
1: Even though ice is made up of water, which is dense, the molecules in ice are spead farther apart than liquid water. This makes ice less dense.
2: With the rock on the boat, water was being displaced by the weight of the boat. Once the rock was dropped into the water, less water was displaced by the float. The rock doesn't change the water level; the thickness of the float did. By removing the rock, the boat could float on top of the water (not displacing any water). In this way, that extra space the boat took up in the water was gone- lowering the level of the water.
3: If there was any way for more of us to get involved in your experiments, I think that would increase participation. I know it is hard with so many students, but it is just a thought.
4: How does a lava lamp work?

lecture preflight 05
1: Because ice is less dense than water. Even though ice is water, in its form it is less than water.
2: The rock reduces the amount of weight in the boat. Thus because the boat is lighter it weighs less in the water and instead of having that extra weight be in the boat it is in the water itself because it sunk.
3: I like using the hand remotes, but they are usually gone by the time I get to class. I haven't got to use one yet. Also, I live off campus so I'm a bit late sometimes. If the remotes were put in the back of the room rather than the front I would use it. But I won't interrupt class after coming in late and walk to the front of the room to get one.
4: How can submarines stay under pressure?

lecture preflight 05
1: It is less dense then the liquid form of water.
2: When the rock was in the boat, it displaced the same amount of water as it weighs, but once the rock was on the bottom of the pool, the rock displaced only its volume in water. Since it is more dense than water the rock displaced more while in the boat than while on the bottom.
3: I do not know.
4: Is green beer more dense then regular beer?

lecture preflight 05
1: Ice floats because its density is less than 1g/ml
2: The level of the water is lower because the boat became lighter after dropping the rock out of the boat.
3: I like the lectures. I think the the examples in class are typically the most interesting part.
4: I'm not sure if this has to do with science, but why can't you use electronic devices on an airplane until you reach a certain height?

lecture preflight 05
1: Because it is less dense than water. When water freezes and turns to ice the chemical bonds holding the water molecules together undergo some sort of change that must make them lighter than just water, so ice is less dense and therefore floats on water.
2: When the rock was in the boat, the boat was heavier so more water was pushing up against the side of the boat to keep it afloat. Then, when the rock was dropped into the water the mass in the boat was less so less water was pushing up against the side of the boat to keep it afloat, so even though the volume of the rock didnt change, where its mass was did so the water didnt have to push on the boat as much to keep it floating.
3: Wednesday's lectures are interesting but one thing that could be changed is to not go over the labs/homework as much but extend the information with other experiments.
4: I thought that in order for there to be a thunderstorm there has to be different air masses of different temperatures, which I thought only usually happened in the late spring, summer, and early fall.. so how come over the weekend in chicago it was a wintry mix of snow and freezing rain, and there was also thunder and lightning?

lecture preflight 05
1: Ice floats because it is less dense than water.
2: It is because the boat does not have the same mass now. The pressure from the boat was larger with the rock and caused the water level to rise. It you push down on an object floating the water will rise if you let go the water level will go down. But by putting the rock at the bottom of the pool causes the water to rise very little compared to if it was floating before.
3: I believe that the class is very interesting but the fact that not everyone is showing up is due to factors out of your control: the building is so far away,its winter, it is probabaly everyones last class of the day so we are just tired and want to go home. The only way I think to make people come to class which many may not agree with is having it worth participation points.
4: What causes static? and why is it more abundant in the winter?

lecture preflight 05
1: Water is more dense than ice. I'm not sure why, it must have a density of less than one.
2: The rock was weighing down the entire boat, which was bigger than the rock. When the rock was removed from the boat, the boat rose, allowing the water level to receed. The amount of water raised because of the rock isn't as much as is replaced when the boat moves closer to the pool's surface.
3: I really enjoy lecture, so I don't have any suggestions.
4: Why when you mix baking soda with vinegar does it fizz?

lecture preflight 05
1: Ice floats because it is less dense than water
2: Because the rock was not floating on top of the water anymore, the rock sank and raised the water level.
3: I like the interactive questions. Also, the expierments are cool. Keep it up!
4: How does taking vitimins help your body so much?

lecture preflight 05
1: less dense than water
2: the boat is lighter and it floats up a bit lowering teh level of the water.
3: i thought it was fine
4: how come big ships that i thought were super dense do not sink. how do they make them so they dont

lecture preflight 05
1: It has air pockets that keep its density less than water.
2: The water moved inside the air pockets of the rock.
3: I think the main elements of an exciting class is high energy by the teacher and possibly class participation. Maybe include students in any experiments you perform.
4: Why does hair frizz in certain weather?

lecture preflight 05
1: Ice is less dense than water, so it floats.
2: When the rock was in the boat, it added extra weight to the boat. Once it was removed, the boat was lighter and less submerged in the water. As a result the water level in the pool is lower because less water is displaced by the boat.
3: I think lecture is fun and interesting. I enjoy your class and I like the random intersting experiments!
4: How do the chemicals in sun tan lotion block UV rays?

lecture preflight 05
1: Ice floats because it is a solid that is less dense than a liquid. A magnificant event.
2: The boat was holding the rock above water; therefore, when the rock was placed back into the pool. The water raised because of the displacement of water due to the density and weight of the rock.
3: I really enjoy attending lecture. I think that you are doing a great job! I get excited when you show us enlightening experiments that are mostly kid friendly :)
4: This might be kind of a crazy question, but how does electricity actually work?!

lecture preflight 05
1: The density of the water is greater than the density of the ice.
2: The rock might have added weight to the boat which made the water level rise. So when the weight was alleviate from the boat, the water level might have lowered as well.
3: I think more iclicker questions can facilitate more discussion
4: Why do you have to let the sink water sit before putting fish into it?

lecture preflight 05
1: because it is less dense than water
2: Some of the water spilled out of the pool
3: I like when you answer people's questions because it is always fun being able to explain everyday science occurances to my friends!
4: How does a cruise ship float?

lecture preflight 05
1: because it's less dense than water in tis liquid form.
2: Because the weight that was helping the boat to cause the water level rise was lifted off of the boat.
3: I think your lectures are great. Maybe it was just us that was less energetic than usual??
4: Best way to walk on ice without slipping..

lecture preflight 05
1: Ice floats because it is less dense than water.
2: The boat is not sinking as low because it weighs less than it used to.
3: I enjoyed the demonstrations a lot. I personally like it as it is.
4: What's the difference between a blimp and a hot air balloon?

lecture preflight 05
1: when ice freezes it takes in air, causing expansion of volume, and leaving the ice less dense when frozen than in liquid water form. ice is less dense, so it floats.
2: the rock was pushing the boat down, displacing a lot of water because the boat has a large bottom surface area. without the extra weight in the boat, the boat rides a little higher out of the water, lowering the water level.
3: I think the concepts were so basic people got bored. There were no surprises. =( Try to think of a situation where something acts differently than most people would predict. (i.e. the corn starch bowl)
4: Why don't all birds fly south? and why does it seem like some are still migrating.

lecture preflight 05
1: because it is less dense than water...when water freezes its atoms expand making it less dense
2: the weight that is gone from the boat (i.e. the rock) makes the boat lighter and thus it raises higher in the water...making the water level appear lower.
3: maybe use more participation via the clicker things!
4:

lecture preflight 05
1: Because it less dense than water.
2: This is hard to explain! When the rock is in the boat, the weight of the rock is dispersed on the total surface area of the part of the boat that is in contact with the water. This increases the surface volume of the object displacing the water. And when the rock is placed in the water, the surface area and volume of it are much smaller than the weight that is displaced on the large surface area of the boat (which would create more water to then be displaced), so the amount of water displaced is much lower.
3: ?
4: What is it in stain removers that take away the stain, without effecting the material to which it is being applied?

lecture preflight 05
1: ice has less density than water
2: The water level is lower because when the rock is in the boat, it creates more mass so the boat sinks more, therefore, displacing more water. Without the rock in the boat, less water is displaced because the boat isn't submerged as much.
3: I really enjoy the experiments you do because they help me understand the concepts better. Maybe do like a crazy one each week.
4: Why doesn't vodka freeze?

lecture preflight 05
1: it is less dense than water
2: the weight of the rock causes the boat hwich has more urface area to displace more water. When the rock is thrown in the valume of the rock displaces less water than when attached to the boat
3: Blow up more stuff.
4: How do ice skates work?

lecture preflight 05
1: Ice floats because it has a greater density than water in its liquid state.
2: The water was displaced when the rock was put in. Also, the rock sinks becuase it has a higher density than the water.
3: I think the lectures are interesting as is. Keep up the good work!
4: What is the density of Coke?

lecture preflight 05
1: Ice floats because when water is frozen to make ice it becomes less dense.
2: I would say that considering that the rock is no longer at the top of the water when it gooes to the ground it makes less of an impact and thats why the water level drops. Since it was in the boat it was less dense but since it was dropped in the water it became more dense than the water.
3: I actually like lecture but I think that if you had some more ways of getting students engaged with the the lecture and you examples that would help. I guess this would mean to have students volunteer to help you with the experiments you show us in class.
4: where do seeds come from?

lecture preflight 05
1: It has a density less than water because it's mass is less.
2: The weight of the boat is less, so it pushes down on the water less and less of the water is displaced from the weight of the boat.
3: It is fun when you have students participate in the demonstrations.
4: Why is it so humid during the summers?

lecture preflight 05
1: It is less dense than water
2: There is less weight in the boat. The weight was pushing the boat down, causing the level of water to rise in the pool. When the rock was removed from the boat, it took up less space at the bottom the pool than when it was weighing the boat down (which was obviously larger than the rock).
3: I find your lectures interesting and entertaining. I like coming to lecture.
4: What is the difference between black ice and ice that "looks like ice"?

lecture preflight 05
1: It has a density less than 1.
2: The rock was taking up space in the water, which decreased the amount of air that could push on the walls of the boat. Also, it made the boat sink more since it has a large density and weight.
3: It is not your fault the participation in lecture is low, the reason is that the lecture is not required and it's in the late part of the day. You might consider telling the class ahead of time if there is a cool experiment going on in lecture and then I'm sure more people would be motiviated to participate. You might also want to offer an extra credit activity for the class to do during lecture.
4: How do lava lamps work?

lecture preflight 05
1: It's density is less than that of liquid water.
2: It appears lower because less of the boat is submerged now that it's density is less.
3: Nothing. I was at the lecture last week and the experiments were both entertaining and educational.
4: What is the best way to construct a boat out of clay and fit the most hex nuts in it? Is there a specific model that holds the most and why that model?

lecture preflight 05
1: Ice floats because its density is less than the density of water which is about 1gram/milliliter. If the density of an object is less than that of water (1), the object will float.
2: This rising of the water level is called displacement. The volume would not change. Volume is the amount of space that something takes up, and everything has a consant volume because it is always the same number of atoms present.
3: More volunteers from the audience to help you with experiments like you did last week!
4: What exactly makes popcorn pop? Is it a set temperature?

lecture preflight 05
1: Ice floats because it is less dense than water.
2: when the rock was in the boat the extra weight caused the boat to ride lower in the water, displacing more water and making the level higher.
3: Explosions are the best at keeping people's attention.
4: why does it sleet when the weather is warmer than 32 degrees?

lecture preflight 05
1: It has a lower density than water.
2: The rock displaced some of the water, causing some of the water to spill over the side.
3: Hmm ... the only thing I can think of is to answer a few more of the questions we ask each week. I enjoy lecture, especially those when there are a lot of experiments.
4: What does some snow melt faster than other snow, especially when both piles of snow are in the same area?

lecture preflight 05
1: ice is less dense than water
2: The rock made the boat displace more water than just the rock itself.
3: I think lectures on Wednesdays are interesting and fun...
4: how does a lava lamp work?

lecture preflight 05
1: Because ice is less dense than water.
2: because some of the water splashed out of the pool and spilled over when the rock hit the water.
3: Maybe have more of the experiments be student involved- have us do them? and use us as apart of the experiment?
4: is it true, that if you eat after a certain time or before you go to bed you gain more weight?

lecture preflight 05
1: Ice floats because it is less dense than water. When it forms, it takes up more space than it did as a liquid, thus it floats on top of the water.
2: When the rock was in the boat, the mass was larger. Now that the rock is out of the water, the mass of the boat is less, which will cause the boat to float higher than it did before. This means the level of water will seem lower to the person in the boat.
3: Hmm, I'm not good at this! Maybe everyone was just not participating because it is midterm season and students are tired? I think this wednesday will be better! Maybe adding more participation questions with the clicker might help?? Hope this helps!
4: How do lava lamps work?!

lecture preflight 05
1: Because it's less dense than water.
2: 2) mass of boat without rock is less than before, so boat floats higher making water level seem lower
3: Prizes for participation?
4: Why does our voice change when we use helium?

lecture preflight 05
1: Because ice is less dense than water
2: The mass of the boat without the rock is less than before, so the boat floats higher makeing the water level seem lower.
3: I have no suggestions.
4: How much energy do we need on a daily basis to perform necessary tasks?

lecture preflight 05
1: The density of the ice must be lighter than water. Why though, is frozen water lighter than water?
2: The density of the boat was greater when the rock was in it. Therefore the boat was submerged further into the water while the rock was in it. The further the boat was submerged in the water, the higher the water level was. Now that the boat is not submerged as deep as it was, the water level has lowered.
3: I don't know how to encourage more participation, but I will say that the class already is very interesting. Even though attendance isn't taken, I still show up to see the demonstrations because they're usually pretty cool. The only room for class participation is if someone has a question they would have about what you are doing, and they may be too shy to ask.
4: When I look through a glass of water, I notice that everything I see through the glass is reversed. For example if there is a person behind the glass turned and facing my right, it looks like that person is facing to the left if I look through the glass. Why does this happen?

lecture preflight 05
1: because it's density is less than that of water
2: displacement--the object is taking the space of some of the water therefore the water level risees.
3: Well, I love every lecture. I love all the experiements and especially the questions we answer as a class.
4: does sleeping after a meal lead to weight gain? if so why?

lecture preflight 05
1: ice floats because it is less dense than water.
2: I think that since the wood is inside the boat, it is floating when in reality it would sink. I think the wood has more of an impact on the water if it is inside the boat then when it has sunken to the bottom. this is because if it is in the boat, it is less dense then the water, but when it is sunken to the bottom, it is more dense than the water. therefore, I think that the water level is affected more with objects that are less dense.
3: I enjoy lecture because we learn things that people wonder about on a daily basis. I am not sure of how to make it more useful, but maybe have a few activities where you can call students down to the front so we can try some things out ourselves.
4: How are telephones able to transfer calls all over the country? I do not understand how the wires, etc. work to make people able to talk over a telephone.

lecture preflight 05
1: I think that ice floats because when water is in its solid form, it is less dense. Therefore, ice floats when it is in water because the ice is less dense than the water.
2: I think it is because the rock displaces water out of the pool.
3: Maybe ask students to be involved in the experiments. We always like to participate when it's fun!!
4: Why do ears pop?

lecture preflight 05
1: because it is less dense than water
2: the rock displaced some of the water in the pool and then when it leveled out, there was less water
3: more exploding or more drastic examples
4: how do martial artists and gymnasts seem to defy gravity in some of their stunts?

lecture preflight 05
1: ice floats because it is less dense than water
2: the water lever lowers because the boat rises up due to its lowered weight from the loss of the big rock, allowing the water level to rise
3: no suggestions really... i enjoy lecture
4: how does an airplane stay in the air?

lecture preflight 05
1: It is less dense than water.
2: The rock has volume and needs space, for a lack of better words. The amount of water is the same, but the rock has taken up some of the space where the water used to be, so the water level is raised.
3: I think that students feel that they need correct answers when participating in science classes. In my experience, it has been emphasized that we need to have right/exact answers in science to be able to make a quality contribution. It just needs to be "drilled" into our heads that science is about discussing different ideas and solving problems through experimenting, and we will be more comfortable.
4: I'm sitting in the library because the internet/cable is out in my apartment building and I'm surrounded by smelly old books. Why do old books smell so bad?

lecture preflight 05
1: Ice floats because it is less dense than liquid water.
2: It is lower now because before the rock was "floating" because it was inside the floating boat. The rock was displacing water before, but now it is sunk in the pool.
3: I think it was just a weird day. I love your lectures!
4: How come chameleons can change color depending on what surface they are on?

lecture preflight 05
1: ice is probably less dense than liquid water.. so it floats
2: the boat is less sumberged in the water..when we put the clay in the cylinder w/ water the level increased. so, the same thing happened as taking out the clay, the water level went back down.
3: more cool experiments?
4: how does a lava lamp work?

lecture preflight 05
1: The density of ice is less than that of water.
2: The boat is sitting up higher in the water after the rock was dropped because the weight of the boat is now less than before.
3: I don't have any changes.
4: What gives something a smell?

lecture preflight 05
1: Because in solid form, ice is less dense than water.Though they are essentially the same thing, but in different form, ice has more tighter packed molecules than water causing it to float in water.
2: By throwing a rock from your boat into the water, the rock sunk which caused displacement of the water. Therefore, the water that spilled out of the pool caused the level of the water to lower. This is portaying Archimede's principle.
3: Maybe make participation points.
4: How does heat travel in an insulator?

lecture preflight 05
1: Ice is less dense than the water. It is solid and the molecules are arranged more compactly than water. This close arrangement of water molecules in ice allows it to float in water.
2: This is because the rock was initially sitting on the bottom of the boat so its weight was con
3: Offer an extra credit question at the end of class to encourage everyone to participate and increase the attendance :)
4:

lecture preflight 05
1: Ice is less dense in the solid form and therefore floats in water.
2: After dropping the big rock into the pool, some of the water may have overflowed and left the pool, leaving less water inside the pool causing a lower water level.
3:
4: how does water evaporate? can all liquids evaporate?

lecture preflight 05
1: Because it is less dense than water.
2: when the rock was taken out of the boat the mass of the boat was lower. there is less water pushing a the boat to keep it afloat.
3: it is very interesting!
4: how long can a car float in water before it starts to sink

lecture preflight 05
1: Ice is less dense than liquid water
2: Since you took the rock out of the boat, the boat is now displacing less water.
3: I don't know
4: Why are we tired some days and awake others when we got the same amount of sleep both days?

lecture preflight 05
1: Ice is less dense than water.
2: The weight of the boat was heavier when the rock was in it. There for there was more mass displacing the water, making the water level higher. This rising of the water level is called displacement. The volume would not change. Volume is the amount of space that something takes up, and everything has a consant volume because it is always the same number of atoms present. When the rock was thrown into the water, the boat became lighter. Now there was less pressure pushing down on the water
3: I can't think of anything to get a group of students in a lecture more involved. I enjoyed lecture if that counts for anything!
4: Why do fall leaves change color?

lecture preflight 05
1: ice floats because it is less dense than liquid water
2: the rock was probably pushing down on the boat, causing more of the boat to be submerged. when the rock is out of the boat, the boat float higher and the water level is lower.
3: honestly, i think that it has nothing to do with the actual lecture. alot of people are just tired after a long day when 4 o'clock comes around. however, i really like the clickers i think they are a great way to get people involved in lecture. maybe if you asked for more volunteers that would get people more into the expiriments.
4: why and how does gravity work?

lecture preflight 05
1: Ice floats because it is less dense than water. This is because the gas that is released from ice is melting in the water. This causes the density to decrease making the ice stay afloat.
2: This is because the rock that is being thrown out of the boat causes the boat to be less dense. Therefore, the boat is lighter and does not push on the water as much, so the level of the water in the pool is lower than it was before dropping the rock out.
3: I really like watching the experiments. Maybe if you demonstrated the experiments throughout the entire hour rather than just the end?!
4: How is it possible that humans can float and sink in water?

lecture preflight 05
1: Ice floats because it is less dense than water.
2: I think that since the rock was really dense when the rock was on the boat it made the boat heavier and so the water lever was high. When the rock was dropped into the pool it sunk but it wasn't weighing the boat down so it made the water level decrease.
3: Personally I thought the lecture was intresting but we could of seemed like that because of all the exams we had last week and this week. Anyways, I think that if you keep answering and demonstrating why things we oversee happen that would keep us thinking and trying to participate in lecture.
4: Why do lightning bugs leave a greenish yellow glow when they are stepped on?

lecture preflight 05
1: it is distributing its weight evenly and not breaking the surface tension.
2: the rock is not occupying the space that the all water.
3: I'm not sure i think Wednesday is just a tough day for most, but i really enjoy myself.... maybe people are just to lazy at that point in the day well i know i t kinda am... that there should be even more class participation,
4: ok so diamonds are supposedly coal under pressure are there any other elements,mineral, or materials that do that?

lecture preflight 05
1: Ice floats because it is less dense than liquid water.
2: The big rock spashed some water outside of the pool.
3: I really enjoy attending lecture, and I think your doing a great job.
4: Why do you blow a fuse?

lecture preflight 05
1: Ice floats because its density is less than that of water.
2: The added weight of the rock in the boat caused the boat to exert more force on the water, which displaced more water. When the weight of the rock was out of the boat, the lighter boat displaced less water, making the level of the water look lower.
3: I think you are doing a great job and find lecture very interesting.
4: How do those plasma balls that make your hair stand up work?

lecture preflight 05
1: Because it is less dense than water.
2: Your boat displaces less water because the boat (and its contents) now have less mass.
3: Interactive displays are always a good thing - yea its a little embarassing but it keeps students on their toes. More interaction is the key.
4: You claim that you've never broken a microwave but somehow my house has broken two in the last year. One of the girls cooked Easy Mac w/ out the water, could that have broken the microwave?

lecture preflight 05
1: Ice floats because the density of ice is less than the density of water, which is 1 g/ml.
2: The boat lost some weight when the rock was thrown out of it. The boat was more buoyant so less of the boat was in the water, and therefore less water is displaced, lowering the level of the water.
3: It might be more interesting and helpful if the class was more involved in some of the experiments.
4: How can a huge cruise boat filled with people float?

lecture preflight 05
1: Ice floats because when water is in a solid form, it is displacing more water than it weighs.
2: The water is being displaced because of the volume of the rock. The volume that the rock is taking up at the bottom of the pool, the water makes up for by being higher at the top.
3: No, I really enjoy lecture!
4: How do bluetooth headsets on cell phones work?

lecture preflight 05
1: the ice is less dence than the surrounding water.
2: The water level raises because the rock is adding volume to the pool. Just like dropping an object in the graduated cylinder in lab produced the same effect.
3: I think that lecture is interesting!
4: what causes an echo?