Lab Report

Guiding Question: How does the medium change the speed of the wave?

Hypothesis: I think the denser the liquid the slower the wave.

Materials:

• Water
• Sunflower Oil
• Sugar
• Tub
• Timer
• Recording System
• Help From a Friend
• A half and inch diameter tapping tool
• Ruler
• Tape

Procedure:

1. Take your tub and tape you ruler onto the bottom, putting the 1 on the cm side facing you.
2. Fill you tub with about 3 quarters full with water.
3. Set your timer for 10 seconds.
4. Ask you friend to count the wavelength.
5. Start tapping the water with your tapping too and count the frequency.
6. When 10 seconds are up record the wavelength and frequency and then find out the speed and record that too.
7. Do 3 tests before switching mediums.
8. Put sugar in until the water is sticky.
9. Repeat the steps 3 to 7.
10. Then dump the water and pour in the sunflower oil.
11. Do the steps from 3 to 7 again.
12. Your experiment is done.

Data Analysis:

	Water			Sweet water			Sun flower oil
Trial	Hz	Wave length	Speed	Hz	Wave length	Speed	Hz	Wave length	Speed
1	3 Hz	2.5 cm	7.5 cms	3 Hz	2 cm	6 cms	3 Hz	1 cm	3 cms
2	3 Hz	3 cm	9 cms	3 Hz	1.8 cm	5.4 cms	3 Hz	2 cm	6 cms
3	3 Hz	3.2 cm	9.6 cms	3 Hz	1.7 cm	5.1 cms	3 Hz	.75 cm	2.25 cms

Conclusion:
Through this experiment I found that the denser the liquid is, the smaller the wavelength and slower the wave. I support this because with water, the lest dense liquid, the average speed was around 8.5 cm/s and the average wavelength was around 2.8 cm. In the sweet water, which was the 2 densest liquid the average speed of 5.5 cm/s and a wavelength around 1.8 cm. For the sunflower oil, the densest liquid, its average speed was 4 cm/s and wavelength 1.25 cm.

Further Inquiry:
If I was to do this experiment again I would use more mediums and include things like ropes. This way I could see the difference between mediums much better and this way I might be able to prove myself wrong and that's good because in the process I would learn more while making a bit of a mess.

Tectonic Plates

Earthquakes happen when the tectonic plates move around. Tectonic plates are what the earths land is made of, huge pieces of shifting rock. These plates can move in any direction, into each other, pulled away from each other, or scraping each other. This causes the earthquake. Earthquake are recorded on the Richter scale, a scale developed to measure the force of an earthquake. The Richter scale works by 1 on the Richter scale is 1 force, and 2 is 10, and 3 is 100 etc. To find out the force of the earthquake and the epicenter of it, scientists have invented the Seismograph, which is placed all around the world sending data to a database so that scientists can figure out who the earthquake is going to effect, so these seismographs have to work 24/7. The reason the Tectonic plats move around is because under these massive plates is molten lava. So its like putting a bit of water between 2 pieces of ice, the water makes the ice move around at the smallest touch.

How a Ball Boumces

Today we did a lab on how a how a wave reacts when it hits a impassable barrier. To test this without making a big mess we used different density and size balls as our waves. We used a flat wall as our barrier, and we used our hands as the energy that causes the ball to move. In this test we took 3 different size and density balls and we rolled each into a wall 3 times and observe how they react when they hit the wall. to record how the react we rolled them across a piece of paper and recorded their path with different color markers.

First we rolled a big low density Styrofoam ball into the wall 3 times and recorded how it bounced back with a blue marker. This we found wasn't very fast when we rolled it but bounced easily. Then we rolled a medium size medium golf ball into the wall 3 times and recorded its path. This time even though it came out of our hands faster it was slower bouncing off the wall. Last we took our small high density marble and rolled it into the wall 3 times, recording its path. This time it came our of our hand fastest but when it hit the wall it barely managed to roll off the page.

After doing this experiment I learnt that the higher the density the faster it rolls, but the worse it bounces. Which in waves would mean for a fast wave you would need lots of density, but if that hit a impassible barrier it would just slop around. But with the slower low density wave it would bounce back and continue going.

Wave Interactions

In science class we used a tray of water to find out how waves interact. We used the tray of water and 2 clay barriers to find out what would happen when we made waves by shaking the tray

we did this test 3 times without barriers in different directions, 3 times with 1 barrier, and 3 times with 2 barriers.

First, we tested 3 times with no barriers. We shook the waves back and forth, thinking that when the 2 waves from either side met in the middle they would stop but amazingly it seemed that they just passed through each other without even slowing down.

Second, we tested the waves with 1 barrier on the side, this time when we shook the tray we creating 3 different pools of waves. 2 that were very fast but bounced off the barrier and 1 that went to the ends of the tray. Which was very unusual to watch.

Lastly, we put another barrier opposite to the first 1, leaving a small gap in the middle. This time when we shook the tray all the water on one side of the barrier stayed on that side and all the water on the other side stayed there. We predicted that if you put different color food coloring on both sides the wouldn't change any paint even if you shook it.

In conclusion I've learnt that there are many invisible waves all around us that we can't see. Some bouncing off objects depending on the depending on how intense it is.