Water Drops

On our last Wednesday and Thursday, we decided to try one more picture. Mr. Peterson sent us some cool pictures of shapes that water makes when you drop different color water droplets into it. We decided to try this. We took a bowl of clear water. We put a cup of water with sugar (to make the water thicker) and with red dye to make it a different color. We then put a white lid under the bowl so that we could see the water better. Then we took the high speed camera and used the 30 pictures per 1 second thing on the camera. We dropped drops of red water into the clear water. This took a few tries and we had to adjust how we did things. Like at first, we couldn't get the camera to focus. Shane told us to put the dropper into the water, focus the camera on that, then take it out and drops the water and it will focus better. It worked! And this is a good picture that we got:

The Math of Refraction

Snell's Law states: 

ni = the index of refraction of the incident medium (in my case, the air)
nr = the index of refraction of the refraction medium (in my case, the canola oil)
(θi) = angle of incidence (in air)
(θr) = angle of refraction (in canola oil)

In the pictures I took of the glow stick in water and canola oil, this formula can help me find the index of refraction for each substance. The index of refraction is equal to the speed of light in a vacuum (a volume of space with empty matter) divided by the speed of light in the medium. I picked a photo and placed a protractor on it to measure the angles.



The angle of incidence is the angle that the glow stick is sitting in the glass cup and how we see it in the air.

The angle of refraction is the angle at which the glow stick is sitting in the canola oil in the glass and how we see that because of the speed of light.

I know that the index of refraction in air is about 1.0003. The angle of incidence is 29 degrees. The angle of refraction is 37 degrees. Now I can plug these numbers into the equation to find the index of refraction of canola oil.

1.0003 * sin(29) = nr * sin(21)

1.353 = nr 

So the index of refraction of the canola oil is 1.353

Then I can take this and plug it into the equation for index of refraction.

index of refraction = (speed of light in vacuum)/(speed of light in medium)

1.353 = (299792458 m/s)/(speed of light in canola oil)

(299792458 m/s)/(1.353)=speed of light in canola oil

speed of light in canola oil = 221,576,000 m/s


When LIGHT goes from one medium to another, it will bend. When it goes from less dense to more dense, it bends towards. When it goes from more dense to less dense, it bends away. Because I am using a glow stick, which is not light, it is doing the opposite. So The angle is 37 degrees away. That is 8 degrees more than 29 degrees where it originally was. Therefore, I need to subtract 8 from 29 to get 21 degrees. 21 degrees is the angle I will use for the angle of refraction.

Day 17 (and over the weekend)

On Friday, we took a hammer to a few light bulbs... We used the high speed camera to get a picture of the light bulb as it breaks. The first time didn't go so well because we didn't time it right, but the second time we got a sweet picture! We decided to show this in a picture of the pictures all side by side. 

Over the weekend, I took some glow sticks and put them into canola oil and water. This showed the refraction of light very well. This is my essay for this photo and for the aapt.org contest: 

This is a photo of a blue glow stick submerged into a glass filled with water and canola oil. The water and oil separate because oil has non polar ions and water has polar ions which do not mix. Therefore, water and oil are insoluble. The oil has a lower density than the water, so it floats on top of the water. The glow stick seems to be broken at certain points in the oil and water. This is because of refraction of light. Refraction happens when light changes from one medium to another medium. The speed of light changes in different mediums. When the light hits another medium, like the canola oil, the glow stick looks "bent" because the speed of light has decreased. Also, notice how the glow stick appears a little bit bigger in the water than in the oil. This is because as light travels through the water, it bends at odd directions and magnifies the glow stick. 

Emily is entering the breaking light bulb into the contest, and Mackenzie is entering the burning lightbulb filament into the contest.

Day 16

On Thursday, we took some awesome pictures of a light bulb's filament. First, we need lightbulbs, a bunsen burner, matches, a huge beaker, lots of ice, goggles, and gloves. We took the light bulb and held it over the bunsen burner's flame for about 10 seconds. Then we stuck the light bulb's top into the ice water and it broke open. The filament, however, was still in tact. With the filament, we were able to take a high speed picture of the filament burning when you turn the light on. The first shot we took was a fail because the exposure was too high for the camera. But then we placed another light bulb, already lit up, next to the filament so the camera would have already adjusted. This worked! We got some great pictures of this.

Day 14 and 15

On Monday we used Mr. Peterson's black high speed camera which takes 30 pictures in 1 second. It was pretty sweet. We had to time everything just right, but the pictures turn out cool! We had an idea of popping a balloon. We did this first with a normal balloon and we got a shot of it in the midst of popping, so it was faded. Then we took a picture of a water balloon popping. This one turned out sweet too! 

On Tuesday we tried to make a little balloon pop by putting vinegar and baking soda together with the balloon over the top of the flask. It blew up, but it never exploded because we didn't have the right measurements. We tried to do this with a sound trigger, but since the balloon never popped, we never got a good picture. 

Day 13

On Friday, we tried to get a strobe photo of balloons filled with paint and then us popping them. We were prepared. We brought all of the supplies needed, we made sure to get out of our 8th hour class so we could have time to do this, and we knew exactly how we were going to set it all up. First, we drilled holes into the wood so that we could pop the balloons from the back. Second, we filled the balloons with an opposite color paint. We figured out that blowing up the balloon with just wait was going to be difficult, so we put mostly paint in, then we put the balloon over the faucet so that we could blow the balloon up with water. This seemed to work, although it was pretty thin paint. We practiced with a few balloons before we took the actual shot. We put the balloons on the wood by using a staple gun. We place the strobe light on a stool so it was at the right height as the balloons. Then we placed the camera on a higher stool as well. The lighting wasn't great at first, we figured out how to get the strobe closer to the balloon and increase the exposure on the camera. We put the strobe on a "medium" speed and the left the lens open for 15 seconds. We took another strobe photo and it worked! So we thought we'd give the actual picture a try.

We had six total balloons on the wood. We made sure everything was set up correctly: the strobe light, the balloons, the camera. We turned off the lights, I counted down, and pushed the button to take the photo. Emily and Mackenzie popped the balloons within the 15 seconds. It was a mess everywhere. Watery paint was all over the floor. We were really hoping for a good picture at this point... The ground was colorful with water and we needed more towels as soon as possible. Emily was wet with water and this was because three of the balloons didn't end up popping. There were only little holes that were spraying water out the back. I think they weren't blown up tight enough where when we poked a hole in, they didn't need to pop open. 

We looked at the picture and it was awful. First, it was kind of blurry. Second, it was just streams of paint down the wood. Second, the balloons didn't look like they were popped. I have no idea what we could have done to make this any better. By the end of cleaning everything up, looking at the awful picture, and realizing that we didn't have much time left to get any better pictures, we were all very frustrated. We have less than a week until the photos are due and we have none! As for me, I feel very angry and scared that we will not have a good picture in time for the contest due date.

Day 10, 11, 12

The past week we have been working on trying to get our trigger photos to work. On Monday, we couldn't find the flash so we looked everywhere for it. That took up most of our class time and we didn't get anything done that day.

On Wednesday, we still didn't have the second flash so we had to split the class time Shane and Ben. We learned that putting a white tissue paper over the flash will decrease the intensity. This really helped bring the exposure down! We smashed 3 light bulbs with the contact trigger. The first one missed the trigger and the flash didn't go off... the second one hit the trigger, but the flash went off too soon so we only got a picture of the light bulb BEFORE it broke. The third one broke, the flash went off, but it didn't show much of it breaking. It wasn't quite what we were looking for.

On Thursday, today, we found the flash! We now started brain storming ideas of what to do for our final picture. We came up with the idea of hitting balloons filled with paint as a strobe picture so that the balloons will all be popping in the colorful picture. We tried to see what it would look like and how it would work today. We popped balloons with nothing in them, but the pictures didn't really turn out.. we need to still work a little on figuring this out.